1
|
Tsvetkov D, Schleifenbaum J, Wang Y, Kassmann M, Polovitskaya MM, Ali M, Schütze S, Rothe M, Luft FC, Jentsch TJ, Gollasch M. KCNQ5 Controls Perivascular Adipose Tissue-Mediated Vasodilation. Hypertension 2024; 81:561-571. [PMID: 38354270 DOI: 10.1161/hypertensionaha.123.21834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 12/12/2023] [Indexed: 02/16/2024]
Abstract
BACKGROUND Small arteries exhibit resting tone, a partially contracted state that maintains arterial blood pressure. In arterial smooth muscle cells, potassium channels control contraction and relaxation. Perivascular adipose tissue (PVAT) has been shown to exert anticontractile effects on the blood vessels. However, the mechanisms by which PVAT signals small arteries, and their relevance remain largely unknown. We aimed to uncover key molecular components in adipose-vascular coupling. METHODS A wide spectrum of genetic mouse models targeting Kcnq3, Kcnq4, and Kcnq5 genes (Kcnq3-/-, Kcnq4-/-, Kcnq5-/-, Kcnq5dn/dn, Kcnq4-/-/Kcnq5dn/dn, and Kcnq4-/-/Kcnq5-/-), telemetry blood pressure measurements, targeted lipidomics, RNA-Seq profiling, wire-myography, patch-clamp, and sharp-electrode membrane potential measurements was used. RESULTS We show that PVAT causes smooth muscle cell KV7.5 family of voltage-gated potassium (K+) channels to hyperpolarize the membrane potential. This effect relaxes small arteries and regulates blood pressure. Oxygenation of polyunsaturated fats generates oxylipins, a superclass of lipid mediators. We identified numerous oxylipins released by PVAT, which potentiate vasodilatory action in small arteries by opening smooth muscle cell KV7.5 family of voltage-gated potassium (K+) channels. CONCLUSIONS Our results reveal a key molecular function of the KV7.5 family of voltage-gated potassium (K+) channels in the adipose-vascular coupling, translating PVAT signals, particularly oxylipins, to the central physiological function of vasoregulation. This novel pathway opens new therapeutic perspectives.
Collapse
Affiliation(s)
- Dmitry Tsvetkov
- Department of Internal Medicine and Geriatrics, University Medicine Greifswald, Germany (D.T., M.K., M.A., M.G.)
| | - Johanna Schleifenbaum
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Germany (J.S.)
| | - Yibin Wang
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany (Y.W., F.C.L.)
| | - Mario Kassmann
- Department of Internal Medicine and Geriatrics, University Medicine Greifswald, Germany (D.T., M.K., M.A., M.G.)
| | - Maya M Polovitskaya
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany (M.M.P., S.S., T.J.J.)
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (M.M.P., S.S., T.J.J.)
| | - Mohamed Ali
- Department of Internal Medicine and Geriatrics, University Medicine Greifswald, Germany (D.T., M.K., M.A., M.G.)
| | - Sebastian Schütze
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany (M.M.P., S.S., T.J.J.)
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (M.M.P., S.S., T.J.J.)
| | | | - Friedrich C Luft
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany (Y.W., F.C.L.)
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany (M.M.P., S.S., T.J.J.)
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (M.M.P., S.S., T.J.J.)
- NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Berlin, Germany (T.J.J.)
| | - Maik Gollasch
- Department of Internal Medicine and Geriatrics, University Medicine Greifswald, Germany (D.T., M.K., M.A., M.G.)
| |
Collapse
|
2
|
Liu E, Pang K, Liu M, Tan X, Hang Z, Mu S, Han W, Yue Q, Comai S, Sun J. Activation of Kv7 channels normalizes hyperactivity of the VTA-NAcLat circuit and attenuates methamphetamine-induced conditioned place preference and sensitization in mice. Mol Psychiatry 2023; 28:5183-5194. [PMID: 37604975 DOI: 10.1038/s41380-023-02218-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/23/2023]
Abstract
The brain circuit projecting from the ventral tegmental area (VTA) to the nucleus accumbens lateral shell (NAcLat) has a key role in methamphetamine (MA) addiction. As different dopamine (DA) neuron subpopulations in the VTA participate in different neuronal circuits, it is a challenge to isolate these DA neuron subtypes. Using retrograde tracing and Patch-seq, we isolated DA neurons in the VTA-NAcLat circuit in MA-treated mice and performed gene expression profiling. Among the differentially expressed genes, KCNQ genes were dramatically downregulated. KCNQ genes encode Kv7 channel proteins, which modulate neuronal excitability. Injection of both the Kv7.2/3 agonist ICA069673 and the Kv7.4 agonist fasudil into the VTA attenuated MA-induced conditioned place preference and locomotor sensitization and decreased neuronal excitability. Increasing Kv7.2/3 activity decreased neural oscillations, synaptic plasticity and DA release in the VTA-NacLat circuit in MA-treated mice. Furthermore, overexpression of only Kv7.3 channels in the VTA-NacLat circuit was sufficient to attenuate MA-induced reward behavior and decrease VTA neuron excitability. Activation of Kv7 channels in the VTA may become a novel treatment strategy for MA abuse.
Collapse
Affiliation(s)
- E Liu
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Kunkun Pang
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
- Department of Ultrasound, The Second Hospital of Shandong University, Jinan, Shandong, China
| | - Min Liu
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Xu Tan
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Zhaofang Hang
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Shouhong Mu
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Weikai Han
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Qingwei Yue
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Stefano Comai
- Department of Psychiatry, McGill University, Montréal, QC, Canada
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Jinhao Sun
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China.
| |
Collapse
|
3
|
Shorthouse D, Zhuang L, Rahrmann EP, Kosmidou C, Wickham Rahrmann K, Hall M, Greenwood B, Devonshire G, Gilbertson RJ, Fitzgerald RC, Hall BA. KCNQ potassium channels modulate Wnt activity in gastro-oesophageal adenocarcinomas. Life Sci Alliance 2023; 6:e202302124. [PMID: 37748809 PMCID: PMC10520261 DOI: 10.26508/lsa.202302124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/11/2023] [Accepted: 09/11/2023] [Indexed: 09/27/2023] Open
Abstract
Voltage-sensitive potassium channels play an important role in controlling membrane potential and ionic homeostasis in the gut and have been implicated in gastrointestinal (GI) cancers. Through large-scale analysis of 897 patients with gastro-oesophageal adenocarcinomas (GOAs) coupled with in vitro models, we find KCNQ family genes are mutated in ∼30% of patients, and play therapeutically targetable roles in GOA cancer growth. KCNQ1 and KCNQ3 mediate the WNT pathway and MYC to increase proliferation through resultant effects on cadherin junctions. This also highlights novel roles of KCNQ3 in non-excitable tissues. We also discover that activity of KCNQ3 sensitises cancer cells to existing potassium channel inhibitors and that inhibition of KCNQ activity reduces proliferation of GOA cancer cells. These findings reveal a novel and exploitable role of potassium channels in the advancement of human cancer, and highlight that supplemental treatments for GOAs may exist through KCNQ inhibitors.
Collapse
Affiliation(s)
- David Shorthouse
- https://ror.org/02jx3x895 Department of Medical Physics and Biomedical Engineering, Malet Place Engineering Building, University College London, London, UK
| | - Lizhe Zhuang
- Institute for Early Detection, CRUK Cambridge Centre, Cambridge, UK
| | - Eric P Rahrmann
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, UK
| | | | | | - Michael Hall
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, UK
| | - Benedict Greenwood
- https://ror.org/02jx3x895 Department of Medical Physics and Biomedical Engineering, Malet Place Engineering Building, University College London, London, UK
| | - Ginny Devonshire
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, UK
| | - Richard J Gilbertson
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, UK
| | | | - Benjamin A Hall
- https://ror.org/02jx3x895 Department of Medical Physics and Biomedical Engineering, Malet Place Engineering Building, University College London, London, UK
| |
Collapse
|
4
|
Olivencia MA, Villegas-Esguevillas M, Sancho M, Barreira B, Paternoster E, Adão R, Larriba MJ, Cogolludo A, Perez-Vizcaino F. Vitamin D Receptor Deficiency Upregulates Pulmonary Artery Kv7 Channel Activity. Int J Mol Sci 2023; 24:12350. [PMID: 37569725 PMCID: PMC10418734 DOI: 10.3390/ijms241512350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/26/2023] [Accepted: 07/29/2023] [Indexed: 08/13/2023] Open
Abstract
Recent evidence suggests that vitamin D is involved in the development of pulmonary arterial hypertension (PAH). The aim of this study was to analyze the electrophysiological and contractile properties of pulmonary arteries (PAs) in vitamin D receptor knockout mice (Vdr-/-). PAs were dissected and mounted in a wire myograph. Potassium membrane currents were recorded in freshly isolated PA smooth muscle cells (PASMCs) using the conventional whole-cell configuration of the patch-clamp technique. Potential vitamin D response elements (VDREs) in Kv7 channels coding genes were studied, and their protein expression was analyzed. Vdr-/- mice did not show a pulmonary hypertensive phenotype, as neither right ventricular hypertrophy nor endothelial dysfunction was apparent. However, resistance PA from these mice exhibited increased response to retigabine, a Kv7 activator, compared to controls and heterozygous mice. Furthermore, the current sensitive to XE991, a Kv7 inhibitor, was also higher in PASMCs from knockout mice. A possible VDRE was found in the gene coding for KCNE4, the regulatory subunit of Kv7.4. Accordingly, Vdr-/- mice showed an increased expression of KCNE4 in the lungs, with no changes in Kv7.1 and Kv7.4. These results indicate that the absence of Vdr in mice, as occurred with vitamin D deficient rats, is not sufficient to induce PAH. However, the contribution of Kv7 channel currents to the regulation of PA tone is increased in Vdr-/- mice, resembling animals and humans suffering from PAH.
Collapse
Affiliation(s)
- Miguel A Olivencia
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, 28040 Madrid, Spain
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), 28009 Madrid, Spain
| | - Marta Villegas-Esguevillas
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, 28040 Madrid, Spain
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), 28009 Madrid, Spain
| | - Maria Sancho
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), 28009 Madrid, Spain
- Department of Physiology, School of Medicine, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Bianca Barreira
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, 28040 Madrid, Spain
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), 28009 Madrid, Spain
| | - Elena Paternoster
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, 28040 Madrid, Spain
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), 28009 Madrid, Spain
| | - Rui Adão
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, 28040 Madrid, Spain
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), 28009 Madrid, Spain
| | - María Jesús Larriba
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28029 Madrid, Spain
- Ciber Cáncer (CIBERONC), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital Universitario La Paz (IdiPAZ), 28029 Madrid, Spain
| | - Angel Cogolludo
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, 28040 Madrid, Spain
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), 28009 Madrid, Spain
| | - Francisco Perez-Vizcaino
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, 28040 Madrid, Spain
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), 28009 Madrid, Spain
| |
Collapse
|
5
|
Henton A, Zhao Y, Tzounopoulos T. A Role for KCNQ Channels on Cell Type-Specific Plasticity in Mouse Auditory Cortex after Peripheral Damage. J Neurosci 2023; 43:2277-2290. [PMID: 36813573 PMCID: PMC10072297 DOI: 10.1523/jneurosci.1070-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 02/24/2023] Open
Abstract
Damage to sensory organs triggers compensatory plasticity mechanisms in sensory cortices. These plasticity mechanisms result in restored cortical responses, despite reduced peripheral input, and contribute to the remarkable recovery of perceptual detection thresholds to sensory stimuli. Overall, peripheral damage is associated with a reduction of cortical GABAergic inhibition; however, less is known about changes in intrinsic properties and the underlying biophysical mechanisms. To study these mechanisms, we used a model of noise-induced peripheral damage in male and female mice. We uncovered a rapid, cell type-specific reduction in the intrinsic excitability of parvalbumin-expressing neurons (PVs) in layer (L) 2/3 of auditory cortex. No changes in the intrinsic excitability of either L2/3 somatostatin-expressing or L2/3 principal neurons (PNs) were observed. The decrease in L2/3 PV excitability was observed 1, but not 7, d after noise exposure, and was evidenced by a hyperpolarization of the resting membrane potential, depolarization of the action potential threshold, and reduction in firing frequency in response to depolarizing current. To uncover the underlying biophysical mechanisms, we recorded potassium currents. We found an increase in KCNQ potassium channel activity in L2/3 PVs of auditory cortex 1 d after noise exposure, associated with a hyperpolarizing shift in the minimal voltage activation of KCNQ channels. This increase contributes to the decreased intrinsic excitability of PVs. Our results highlight cell-type- and channel-specific mechanisms of plasticity after noise-induced hearing loss and will aid in understanding the pathologic processes involved in hearing loss and hearing loss-related disorders, such as tinnitus and hyperacusis.SIGNIFICANCE STATEMENT Noise-induced damage to the peripheral auditory system triggers central plasticity that compensates for the reduced peripheral input. The mechanisms of this plasticity are not fully understood. In the auditory cortex, this plasticity likely contributes to the recovery of sound-evoked responses and perceptual hearing thresholds. Importantly, other functional aspects of hearing do not recover, and peripheral damage may also lead to maladaptive plasticity-related disorders, such as tinnitus and hyperacusis. Here, after noise-induced peripheral damage, we highlight a rapid, transient, and cell type-specific reduction in the excitability of layer 2/3 parvalbumin-expressing neurons, which is due, at least in part, to increased KCNQ potassium channel activity. These studies may highlight novel strategies for enhancing perceptual recovery after hearing loss and mitigating hyperacusis and tinnitus.
Collapse
Affiliation(s)
- Amanda Henton
- Pittsburgh Hearing Research Center and Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
- Center for Neuroscience, University of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Yanjun Zhao
- Pittsburgh Hearing Research Center and Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Thanos Tzounopoulos
- Pittsburgh Hearing Research Center and Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| |
Collapse
|
6
|
Hernandez CC, Tarfa RA, Miguel I Limcaoco J, Liu R, Mondal P, Hill C, Keith Duncan R, Tzounopoulos T, Stephenson CRJ, O'Meara MJ, Wipf P. Development of an automated screen for Kv7.2 potassium channels and discovery of a new agonist chemotype. Bioorg Med Chem Lett 2022; 71:128841. [PMID: 35671848 PMCID: PMC9469649 DOI: 10.1016/j.bmcl.2022.128841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/11/2022] [Accepted: 06/01/2022] [Indexed: 01/11/2023]
Abstract
To identify pore domain ligands on Kv7.2 potassium ion channels, we compared wild-type (WT) and W236L mutant Kv7.2 channels in a series of assays with previously validated and novel agonist chemotypes. Positive controls were retigabine, flupirtine, and RL-81; i.e. Kv7.2 channel activators that significantly shift voltage-dependent activation to more negative potentials (ΔV50) at 5 µM. We identified 6 new compounds that exhibited differential enhancing activity between WT and W236L mutant channels. Whole cell patch-clamp electrophysiology studies were conducted to identify Kv7.2. Kv7.2/3, Kv7.4, and Kv7.5 selectivity. Our results validate the SyncroPatch platform and establish new structure activity relationships (SAR). Specifically, in addition to selective Kv7.2, Kv7.2/3, Kv7.4. and Kv7.5 agonists, we identified a novel chemotype, ZK-21, a 4-aminotetrahydroquinoline that is distinct from any of the previously described Kv7 channel modifiers. Using flexible receptor docking, ZK-21 was predicted to be stabilized by W236 and bind perpendicular to retigabine, burying the benzyl carbamate group into a tunnel reaching the core of the pore domain.
Collapse
Affiliation(s)
- Ciria C Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Rahilla A Tarfa
- Department of Otolaryngology, Pittsburgh Hearing Research Center, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Jose Miguel I Limcaoco
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, United States
| | - Ruiting Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Pravat Mondal
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Clare Hill
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States; Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - R Keith Duncan
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI 48109, United States
| | - Thanos Tzounopoulos
- Department of Otolaryngology, Pittsburgh Hearing Research Center, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Corey R J Stephenson
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - Matthew J O'Meara
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, United States
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States; Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15213, United States; School of Pharmacy, University of Eastern Finland, 70210 Kuopio, Finland
| |
Collapse
|
7
|
Abstract
Since prehistory, human species have depended on plants for both food and medicine. Even in countries with ready access to modern medicines, alternative treatments are still highly regarded and commonly used. Unlike modern pharmaceuticals, many botanical medicines are in widespread use despite a lack of safety and efficacy data derived from controlled clinical trials and often unclear mechanisms of action. Contributing to this are the complex and undefined composition and likely multifactorial mechanisms of action and multiple targets of many botanical medicines. Here, we review the newfound importance of the ubiquitous KCNQ subfamily of voltage-gated potassium channels as targets for botanical medicines, including basil, capers, cilantro, lavender, fennel, chamomile, ginger, and Camellia, Sophora, and Mallotus species. We discuss the implications for the traditional use of these plants for disorders such as seizures, hypertension, and diabetes and the molecular mechanisms of plant secondary metabolite effects on KCNQ channels.
Collapse
Affiliation(s)
- Kaitlyn E Redford
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California 92697, USA;
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California 92697, USA;
| |
Collapse
|
8
|
Nickerson AJ, Rottgen TS, Rajendran VM. Activation of KCNQ (K V7) K + channels in enteric neurons inhibits epithelial Cl - secretion in mouse distal colon. Am J Physiol Cell Physiol 2021; 320:C1074-C1087. [PMID: 33852365 PMCID: PMC8285638 DOI: 10.1152/ajpcell.00536.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 12/14/2022]
Abstract
Voltage-gated Kv7 (KCNQ family) K+ channels are expressed in many neuronal populations and play an important role in regulating membrane potential by generating a hyperpolarizing K+ current and decreasing cell excitability. However, the role of KV7 channels in the neural regulation of intestinal epithelial Cl- secretion is not known. Cl- secretion in mouse distal colon was measured as a function of short-circuit current (ISC), and pharmacological approaches were used to test the hypothesis that activation of KV7 channels in enteric neurons would inhibit epithelial Cl- secretion. Flupirtine, a nonselective KV7 activator, inhibited basal Cl- secretion in mouse distal colon and abolished or attenuated the effects of drugs that target various components of enteric neurotransmission, including tetrodotoxin (NaV channel blocker), veratridine (NaV channel activator), nicotine (nicotinic acetylcholine receptor agonist), and hexamethonium (nicotinic antagonist). In contrast, flupritine did not block the response to epithelium-targeted agents VIP (endogenous VPAC receptor ligand) or carbachol (nonselective cholinergic agonist). Flupirtine inhibited Cl- secretion in both full-thickness and seromuscular-stripped distal colon (containing the submucosal, but not myenteric plexus) but generated no response in epithelial T84 cell monolayers. KV7.2 and KV7.3 channel proteins were detected by immunofluorescence in whole mount preparations of the submucosa from mouse distal colon. ICA 110381 (KV7.2/7.3 specific activator) inhibited Cl- secretion comparably to flupirtine. We conclude that KV7 channel activators inhibit neurally driven Cl- secretion in the colonic epithelium and may therefore have therapeutic benefit in treating pathologies associated with hyperexcitable enteric nervous system, such as irritable bowel syndrome with diarrhea (IBS-D).
Collapse
Affiliation(s)
- Andrew J Nickerson
- Departments of Physiology, Pharmacology and Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Trey S Rottgen
- Departments of Physiology, Pharmacology and Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Vazhaikkurichi M Rajendran
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Medicine, West Virginia University School of Medicine, Morgantown, West Virginia
| |
Collapse
|
9
|
Sevilla-Montero J, Labrousse-Arias D, Fernández-Pérez C, Fernández-Blanco L, Barreira B, Mondéjar-Parreño G, Alfaro-Arnedo E, López IP, Pérez-Rial S, Peces-Barba G, Pichel JG, Peinado VI, Cogolludo Á, Calzada MJ. Cigarette Smoke Directly Promotes Pulmonary Arterial Remodeling and Kv7.4 Channel Dysfunction. Am J Respir Crit Care Med 2021; 203:1290-1305. [PMID: 33306938 DOI: 10.1164/rccm.201911-2238oc] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 12/10/2020] [Indexed: 01/10/2023] Open
Abstract
Rationale: Cigarette smoke is considered the chief leading cause of chronic obstructive pulmonary disease (COPD). Its impact on the progressive deterioration of airways has been extensively studied, but its direct effects on the pulmonary vasculature are less known. Objectives: To prove that pulmonary arterial remodeling in patients with COPD is not just a consequence of alveolar hypoxia but also due to the direct effects of cigarette smoke on the pulmonary vascular bed. Methods: We have used different molecular and cell biology approaches, as well as traction force microscopy, wire myography, and patch-clamp techniques in human cells and freshly isolated pulmonary arteries. In addition, we relied on in vivo models and human samples to analyze the effects of cigarette smoke on pulmonary vascular tone alterations. Measurements and Main Results: Cigarette smoke extract exposure directly promoted a hypertrophic, senescent phenotype that in turn contributed, through the secretion of inflammatory molecules, to an increase in the proliferative potential of nonexposed cells. Interestingly, these effects were significantly reversed by antioxidants. Furthermore, cigarette smoke extract affected cell contractility and dysregulated the expression and activity of the voltage-gated K+ channel Kv7.4. This contributed to the impairment of vasoconstriction and vasodilation responses. Most importantly, the levels of this channel were diminished in the lungs of smoke-exposed mice, smokers, and patients with COPD. Conclusions: Cigarette smoke directly contributes to pulmonary arterial remodeling through increased cell senescence, as well as vascular tone alterations because of diminished levels and function in the Kv7.4 channel. Strategies targeting these pathways may lead to novel therapies for COPD.
Collapse
Affiliation(s)
- Javier Sevilla-Montero
- Biomedical Research Institute La Princesa Hospital, Madrid, Spain
- Department of Medicine, School of Medicine, and
- Doctoral School, Autonoma University of Madrid, Madrid, Spain
| | - David Labrousse-Arias
- Biomedical Research Institute La Princesa Hospital, Madrid, Spain
- Department of Medicine, School of Medicine, and
| | - Cintia Fernández-Pérez
- Biomedical Research Institute La Princesa Hospital, Madrid, Spain
- Department of Medicine, School of Medicine, and
| | - Laura Fernández-Blanco
- Biomedical Research Institute La Princesa Hospital, Madrid, Spain
- Department of Medicine, School of Medicine, and
| | - Bianca Barreira
- Department of Pharmacology and Toxicology, School of Medicine, Complutense University of Madrid, Madrid, Spain
- Biomedical Research Networking Center in Respiratory Diseases, Institute of Health Carlos III, Madrid, Spain
| | - Gema Mondéjar-Parreño
- Department of Pharmacology and Toxicology, School of Medicine, Complutense University of Madrid, Madrid, Spain
- Biomedical Research Networking Center in Respiratory Diseases, Institute of Health Carlos III, Madrid, Spain
| | - Elvira Alfaro-Arnedo
- Lung Cancer and Respiratory Diseases Unit, Biomedical Research Center of La Rioja, Rioja Salud Foundation, Logroño, Spain
| | - Icíar P López
- Lung Cancer and Respiratory Diseases Unit, Biomedical Research Center of La Rioja, Rioja Salud Foundation, Logroño, Spain
| | - Sandra Pérez-Rial
- Biomedical Research Networking Center in Respiratory Diseases, Institute of Health Carlos III, Madrid, Spain
- Respiratory Research Unit, Biomedical Research Unit, Health Research Institute Fundación Jiménez Díaz, Madrid, Spain; and
| | - Germán Peces-Barba
- Biomedical Research Networking Center in Respiratory Diseases, Institute of Health Carlos III, Madrid, Spain
- Respiratory Research Unit, Biomedical Research Unit, Health Research Institute Fundación Jiménez Díaz, Madrid, Spain; and
| | - José G Pichel
- Biomedical Research Networking Center in Respiratory Diseases, Institute of Health Carlos III, Madrid, Spain
- Lung Cancer and Respiratory Diseases Unit, Biomedical Research Center of La Rioja, Rioja Salud Foundation, Logroño, Spain
| | - Víctor Ivo Peinado
- Biomedical Research Networking Center in Respiratory Diseases, Institute of Health Carlos III, Madrid, Spain
- Department of Pulmonary Medicine, Hospital August Pi i Sunyer Biomedical Research Institute, University of Barcelona, Barcelona, Spain
| | - Ángel Cogolludo
- Department of Pharmacology and Toxicology, School of Medicine, Complutense University of Madrid, Madrid, Spain
- Biomedical Research Networking Center in Respiratory Diseases, Institute of Health Carlos III, Madrid, Spain
| | - María J Calzada
- Biomedical Research Institute La Princesa Hospital, Madrid, Spain
- Department of Medicine, School of Medicine, and
| |
Collapse
|
10
|
Tsai YM, Jones F, Mullen P, Porter KE, Steele D, Peers C, Gamper N. Vascular Kv7 channels control intracellular Ca 2+ dynamics in smooth muscle. Cell Calcium 2020; 92:102283. [PMID: 32950876 PMCID: PMC7695684 DOI: 10.1016/j.ceca.2020.102283] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 01/23/2023]
Abstract
Voltage-gated Kv7 (or KCNQ) channels control activity of excitable cells, including vascular smooth muscle cells (VSMCs), by setting their resting membrane potential and controlling other excitability parameters. Excitation-contraction coupling in muscle cells is mediated by Ca2+ but until now, the exact role of Kv7 channels in cytosolic Ca2+ dynamics in VSMCs has not been fully elucidated. We utilised microfluorimetry to investigate the impact of Kv7 channel activity on intracellular Ca2+ levels and electrical activity of rat A7r5 VSMCs and primary human internal mammary artery (IMA) SMCs. Both, direct (XE991) and G protein coupled receptor mediated (vasopressin, AVP) Kv7 channel inhibition induced robust Ca2+ oscillations, which were significantly reduced in the presence of Kv7 channel activator, retigabine, L-type Ca2+ channel inhibitor, nifedipine, or T-type Ca2+ channel inhibitor, NNC 55-0396, in A7r5 cells. Membrane potential measured using FluoVolt exhibited a slow depolarisation followed by a burst of sharp spikes in response to XE991; spikes were temporally correlated with Ca2+ oscillations. Phospholipase C inhibitor (edelfosine) reduced AVP-induced, but not XE991-induced Ca2+ oscillations. AVP and XE991 induced a large increase of [Ca2+]i in human IMA, which was also attenuated with retigabine, nifedipine and NNC 55-0396. RT-PCR, immunohistochemistry and electrophysiology suggested that Kv7.5 was the predominant Kv7 subunit in both rat and human arterial SMCs; CACNA1C (Cav1.2; L-type) and CACNA1 G (Cav3.1; T-type) were the most abundant voltage-gated Ca2+ channel gene transcripts in both types of VSMCs. This study establishes Kv7 channels as key regulators of Ca2+ signalling in VSMCs with Kv7.5 playing a dominant role.
Collapse
Affiliation(s)
- Yuan-Ming Tsai
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom; Division of Thoracic Surgery, Department of Surgery, Tri-Service General Hospital, National Defence Medical Centre, Taipei 11490, Taiwan.
| | - Frederick Jones
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Pierce Mullen
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Karen E Porter
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Derek Steele
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Chris Peers
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Nikita Gamper
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom.
| |
Collapse
|
11
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
12
|
Rivas-Ramírez P, Reboreda A, Rueda-Ruzafa L, Herrera-Pérez S, Lamas JA. Contribution of KCNQ and TREK Channels to the Resting Membrane Potential in Sympathetic Neurons at Physiological Temperature. Int J Mol Sci 2020; 21:E5796. [PMID: 32806753 PMCID: PMC7461115 DOI: 10.3390/ijms21165796] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/31/2020] [Accepted: 08/10/2020] [Indexed: 12/19/2022] Open
Abstract
The ionic mechanisms controlling the resting membrane potential (RMP) in superior cervical ganglion (SCG) neurons have been widely studied and the M-current (IM, KCNQ) is one of the key players. Recently, with the discovery of the presence of functional TREK-2 (TWIK-related K+ channel 2) channels in SCG neurons, another potential main contributor for setting the value of the resting membrane potential has appeared. In the present work, we quantified the contribution of TREK-2 channels to the resting membrane potential at physiological temperature and studied its role in excitability using patch-clamp techniques. In the process we have discovered that TREK-2 channels are sensitive to the classic M-current blockers linopirdine and XE991 (IC50 = 0.310 ± 0.06 µM and 0.044 ± 0.013 µM, respectively). An increase from room temperature (23 °C) to physiological temperature (37 °C) enhanced both IM and TREK-2 currents. Likewise, inhibition of IM by tetraethylammonium (TEA) and TREK-2 current by XE991 depolarized the RMP at room and physiological temperatures. Temperature rise also enhanced adaptation in SCG neurons which was reduced due to TREK-2 and IM inhibition by XE991 application. In summary, TREK-2 and M currents contribute to the resting membrane potential and excitability at room and physiological temperature in the primary culture of mouse SCG neurons.
Collapse
Affiliation(s)
- Paula Rivas-Ramírez
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
| | - Antonio Reboreda
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
- Functional Architecture of Memory Department, Leibniz-Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Lola Rueda-Ruzafa
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
| | - Salvador Herrera-Pérez
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
| | - Jose Antonio Lamas
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
| |
Collapse
|
13
|
Hoppe K, Chaiklieng S, Lehmann-Horn F, Jurkat-Rott K, Wearing S, Klingler W. Preclinical pharmacological in vitro investigations on low chloride conductance myotonia: effects of potassium regulation. Pflugers Arch 2020; 472:1481-1494. [PMID: 32748018 DOI: 10.1007/s00424-020-02410-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022]
Abstract
In myotonia, reduced Cl- conductance of the mutated ClC-1 channels causes hindered muscle relaxation after forceful voluntary contraction due to muscle membrane hyperexcitability. Repetitive contraction temporarily decreases myotonia, a phenomena called "warm up." The underlying mechanism for the reduction of hyperexcitability in warm-up is currently unknown. Since potassium displacement is known to reduce excitability in, for example, muscle fatigue, we characterized the role of potassium in native myotonia congenita (MC) muscle. Muscle specimens of ADR mice (an animal model for low gCl- conductance myotonia) were exposed to increasing K+ concentrations. To characterize functional effects of potassium ion current, the muscle of ADR mice was exposed to agonists and antagonists of the big conductance Ca2+-activated K+ channel (BK) and the voltage-gated Kv7 channel. Effects were monitored by functional force and membrane potential measurements. By increasing [K+]0 to 5 mM, the warm-up phenomena started earlier and at [K+]0 7 mM only weak myotonia was detected. The increase of [K+]0 caused a sustained membrane depolarization accompanied with a reduction of myotonic bursts in ADR mice. Retigabine, a Kv7.2-Kv7.5 activator, dose-dependently reduced relaxation deficit of ADR myotonic muscle contraction and promoted the warm-up phenomena. In vitro results of this study suggest that increasing potassium conductivity via activation of voltage-gated potassium channels enhanced the warm-up phenomena, thereby offering a potential therapeutic treatment option for myotonia congenita.
Collapse
Affiliation(s)
- Kerstin Hoppe
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital of Wuerzburg, Oberduerrbacher Str. 6, 97080, Wuerzburg, Germany.
| | - Sunisa Chaiklieng
- Division of Neurophysiology in the Center of Rare Diseases, Ulm University, Albert Einstein Allee 23, 89081, Ulm, Germany
- Faculty of Public Health, Khon Kaen University, Muang Khon Kaen, Thailand
| | - Frank Lehmann-Horn
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital of Wuerzburg, Oberduerrbacher Str. 6, 97080, Wuerzburg, Germany
| | - Karin Jurkat-Rott
- Universtiy Medical Center Ulm, Division of Experimental Anesthesiology, Albert-Einstein-Allee 23, 89081, Ullm, Germany
| | - Scott Wearing
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059, Australia
- Department of Conservative and Rehabilitation Orthopedics, Faculty of Sport and Health Science, Technical University of Munich, Gerog-Brauchle-Ring 60/62, Munich, Germany
| | - Werner Klingler
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059, Australia
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, SRH Clinincs, Hohenzollernstraße 40, 72488, Sigmaringen, Germany
- Department of Conservative and Rehabilitation Orthopedics, Faculty of Sport and Health Science, Technical University of Munich, Gerog-Brauchle-Ring 60/62, Munich, Germany
| |
Collapse
|
14
|
Perez-Flores MC, Lee JH, Park S, Zhang XD, Sihn CR, Ledford HA, Wang W, Kim HJ, Timofeyev V, Yarov-Yarovoy V, Chiamvimonvat N, Rabbitt RD, Yamoah EN. Cooperativity of K v7.4 channels confers ultrafast electromechanical sensitivity and emergent properties in cochlear outer hair cells. Sci Adv 2020; 6:eaba1104. [PMID: 32285007 PMCID: PMC7141818 DOI: 10.1126/sciadv.aba1104] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/14/2020] [Indexed: 05/22/2023]
Abstract
The mammalian cochlea relies on active electromotility of outer hair cells (OHCs) to resolve sound frequencies. OHCs use ionic channels and somatic electromotility to achieve the process. It is unclear, though, how the kinetics of voltage-gated ionic channels operate to overcome extrinsic viscous drag on OHCs at high frequency. Here, we report ultrafast electromechanical gating of clustered Kv7.4 in OHCs. Increases in kinetics and sensitivity resulting from cooperativity among clustered-Kv7.4 were revealed, using optogenetics strategies. Upon clustering, the half-activation voltage shifted negative, and the speed of activation increased relative to solitary channels. Clustering also rendered Kv7.4 channels mechanically sensitive, confirmed in consolidated Kv7.4 channels at the base of OHCs. Kv7.4 clusters provide OHCs with ultrafast electromechanical channel gating, varying in magnitude and speed along the cochlea axis. Ultrafast Kv7.4 gating provides OHCs with a feedback mechanism that enables the cochlea to overcome viscous drag and resolve sounds at auditory frequencies.
Collapse
Affiliation(s)
- Maria C. Perez-Flores
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Jeong H. Lee
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Seojin Park
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Xiao-Dong Zhang
- Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, CA 95616, USA
- Department of Veterans Affairs, Northern California Health Care System, Mather, CA 95655, USA
| | - Choong-Ryoul Sihn
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Hannah A. Ledford
- Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, CA 95616, USA
| | - Wenying Wang
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Hyo Jeong Kim
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Valeriy Timofeyev
- Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, CA 95616, USA
- Department of Veterans Affairs, Northern California Health Care System, Mather, CA 95655, USA
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
| | - Nipavan Chiamvimonvat
- Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, CA 95616, USA
- Department of Veterans Affairs, Northern California Health Care System, Mather, CA 95655, USA
| | - Richard D. Rabbitt
- Departments of Biomedical Engineering, Otolaryngology, and Neuroscience Program, University of Utah, Salt Lake City, UT 84112, USA
- Corresponding author. (E.N.Y.); (R.D.R.)
| | - Ebenezer N. Yamoah
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
- Corresponding author. (E.N.Y.); (R.D.R.)
| |
Collapse
|
15
|
van der Horst J, Manville RW, Hayes K, Thomsen MB, Abbott GW, Jepps TA. Acetaminophen (Paracetamol) Metabolites Induce Vasodilation and Hypotension by Activating Kv7 Potassium Channels Directly and Indirectly. Arterioscler Thromb Vasc Biol 2020; 40:1207-1219. [PMID: 32188278 DOI: 10.1161/atvbaha.120.313997] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Intravenous acetaminophen/paracetamol (APAP) is well documented to cause hypotension. Since the patients receiving intravenous APAP are usually critically ill, any severe hemodynamic changes, as with those associated with APAP, can be life-threatening. The mechanism underlying this dangerous iatrogenic effect of APAP was unknown. Approach and Results: Here, we show that intravenous APAP caused transient hypotension in rats, which was attenuated by the Kv7 channel blocker, linopirdine. APAP metabolite N-acetyl-p-benzoquinone imine caused vasodilatation of rat mesenteric arteries ex vivo. This vasodilatation was sensitive to linopirdine and also the calcitonin gene-related peptide antagonist, BIBN 4096. Further investigation revealed N-acetyl-p-benzoquinone imine stimulates calcitonin gene-related peptide release from perivascular nerves, causing a cAMP-dependent activation of Kv7 channels. We also show that N-acetyl-p-benzoquinone imine enhances Kv7.4 and Kv7.5 channels overexpressed in oocytes, suggesting that it can activate Kv7.4 and Kv7.5 channels directly, to elicit vasodilatation. CONCLUSIONS Direct and indirect activation of Kv7 channels by the APAP metabolite N-acetyl-p-benzoquinone imine decreases arterial tone, which can lead to a drop in blood pressure. Our findings provide a molecular mechanism and potential preventive intervention for the clinical phenomenon of intravenous APAP-dependent transient hypotension.
Collapse
Affiliation(s)
- Jennifer van der Horst
- From the Vascular Biology Group, Department of Biomedical Science (J.v.d.H., K.H., T.A.J.), University of Copenhagen, Denmark
| | - Rian W Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine (R.W.M., G.W.A.)
| | - Katie Hayes
- From the Vascular Biology Group, Department of Biomedical Science (J.v.d.H., K.H., T.A.J.), University of Copenhagen, Denmark
| | - Morten B Thomsen
- Cardiac Electrophysiology Group, Department of Biomedical Science (M.B.T.), University of Copenhagen, Denmark
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine (R.W.M., G.W.A.)
| | - Thomas A Jepps
- From the Vascular Biology Group, Department of Biomedical Science (J.v.d.H., K.H., T.A.J.), University of Copenhagen, Denmark
| |
Collapse
|
16
|
Manville RW, Abbott GW. In silico re-engineering of a neurotransmitter to activate KCNQ potassium channels in an isoform-specific manner. Commun Biol 2019; 2:401. [PMID: 31701029 PMCID: PMC6825221 DOI: 10.1038/s42003-019-0648-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 10/10/2019] [Indexed: 12/18/2022] Open
Abstract
Voltage-gated potassium (Kv) channel dysfunction causes a variety of inherited disorders, but developing small molecules that activate Kv channels has proven challenging. We recently discovered that the inhibitory neurotransmitter γ-aminobutyric acid (GABA) directly activates Kv channels KCNQ3 and KCNQ5. Here, finding that inhibitory neurotransmitter glycine does not activate KCNQs, we re-engineered it in silico to introduce predicted KCNQ-opening properties, screened by in silico docking, then validated the hits in vitro. Attaching a fluorophenyl ring to glycine optimized its electrostatic potential, converting it to a low-nM affinity KCNQ channel activator. Repositioning the phenyl ring fluorine and/or adding a methylsulfonyl group increased the efficacy of the re-engineered glycines and switched their target KCNQs. Combining KCNQ2- and KCNQ3-specific glycine derivatives synergistically potentiated KCNQ2/3 activation by exploiting heteromeric channel composition. Thus, in silico optimization and docking, combined with functional screening of only three compounds, facilitated re-engineering of glycine to develop several potent KCNQ activators.
Collapse
Affiliation(s)
- Rían W. Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA USA
| | - Geoffrey W. Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA USA
| |
Collapse
|
17
|
Abstract
Herbs have a long history of use as folk medicine anticonvulsants, yet the underlying mechanisms often remain unknown. Neuronal voltage-gated potassium channel subfamily Q (KCNQ) dysfunction can cause severe epileptic encephalopathies that are resistant to modern anticonvulsants. Here we report that cilantro (Coriandrum sativum), a widely used culinary herb that also exhibits antiepileptic and other therapeutic activities, is a highly potent KCNQ channel activator. Screening of cilantro leaf metabolites revealed that one, the long-chain fatty aldehyde (E)-2-dodecenal, activates multiple KCNQs, including the predominant neuronal isoform, KCNQ2/KCNQ3 [half maximal effective concentration (EC50), 60 ± 20 nM], and the predominant cardiac isoform, KCNQ1 in complexes with the type I transmembrane ancillary subunit (KCNE1) (EC50, 260 ± 100 nM). (E)-2-dodecenal also recapitulated the anticonvulsant action of cilantro, delaying pentylene tetrazole-induced seizures. In silico docking and mutagenesis studies identified the (E)-2-dodecenal binding site, juxtaposed between residues on the KCNQ S5 transmembrane segment and S4-5 linker. The results provide a molecular basis for the therapeutic actions of cilantro and indicate that this ubiquitous culinary herb is surprisingly influential upon clinically important KCNQ channels.-Manville, R. W., Abbott, G. W. Cilantro leaf harbors a potent potassium channel-activating anticonvulsant.
Collapse
Affiliation(s)
- Rían W. Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California–Irvine, Irvine, California, USA
| | - Geoffrey W. Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California–Irvine, Irvine, California, USA
| |
Collapse
|
18
|
Kim KW, Kim K, Lee H, Suh BC. Ethanol Elevates Excitability of Superior Cervical Ganglion Neurons by Inhibiting Kv7 Channels in a Cell Type-Specific and PI(4,5)P 2-Dependent Manner. Int J Mol Sci 2019; 20:E4419. [PMID: 31500374 PMCID: PMC6770022 DOI: 10.3390/ijms20184419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/13/2022] Open
Abstract
Alcohol causes diverse acute and chronic symptoms that often lead to critical health problems. Exposure to ethanol alters the activities of sympathetic neurons that control the muscles, eyes, and blood vessels in the brain. Although recent studies have revealed the cellular targets of ethanol, such as ion channels, the molecular mechanism by which alcohol modulates the excitability of sympathetic neurons has not been determined. Here, we demonstrated that ethanol increased the discharge of membrane potentials in sympathetic neurons by inhibiting the M-type or Kv7 channel consisting of the Kv7.2/7.3 subunits, which were involved in determining the membrane potential and excitability of neurons. Three types of sympathetic neurons, classified by their threshold of activation and firing patterns, displayed distinct sensitivities to ethanol, which were negatively correlated with the size of the Kv7 current that differs depending on the type of neuron. Using a heterologous expression system, we further revealed that the inhibitory effects of ethanol on Kv7.2/7.3 currents were facilitated or diminished by adjusting the amount of plasma membrane phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). These results suggested that ethanol and PI(4,5)P2 modulated gating of the Kv7 channel in superior cervical ganglion neurons in an antagonistic manner, leading to regulation of the membrane potential and neuronal excitability, as well as the physiological functions mediated by sympathetic neurons.
Collapse
Affiliation(s)
- Kwon-Woo Kim
- Department of Brain and cognitive sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
| | - Keetae Kim
- Department of New biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
| | - Hyosang Lee
- Department of Brain and cognitive sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
| | - Byung-Chang Suh
- Department of Brain and cognitive sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
| |
Collapse
|
19
|
Ambrosino P, Soldovieri MV, Di Zazzo E, Paventi G, Iannotti FA, Mosca I, Miceli F, Franco C, Canzoniero LMT, Taglialatela M. Activation of Kv7 Potassium Channels Inhibits Intracellular Ca 2+ Increases Triggered By TRPV1-Mediated Pain-Inducing Stimuli in F11 Immortalized Sensory Neurons. Int J Mol Sci 2019; 20:ijms20184322. [PMID: 31487785 PMCID: PMC6769798 DOI: 10.3390/ijms20184322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/01/2019] [Accepted: 09/02/2019] [Indexed: 12/11/2022] Open
Abstract
Kv7.2-Kv7.5 channels mediate the M-current (IKM), a K+-selective current regulating neuronal excitability and representing an attractive target for pharmacological therapy against hyperexcitability diseases such as pain. Kv7 channels interact functionally with transient receptor potential vanilloid 1 (TRPV1) channels activated by endogenous and/or exogenous pain-inducing substances, such as bradykinin (BK) or capsaicin (CAP), respectively; however, whether Kv7 channels of specific molecular composition provide a dominant contribution in BK- or CAP-evoked responses is yet unknown. To this aim, Kv7 transcripts expression and function were assessed in F11 immortalized sensorial neurons, a cellular model widely used to assess nociceptive molecular mechanisms. In these cells, the effects of the pan-Kv7 activator retigabine were investigated, as well as the effects of ICA-27243 and (S)-1, two Kv7 activators acting preferentially on Kv7.2/Kv7.3 and Kv7.4/Kv7.5 channels, respectively, on BK- and CAP-induced changes in intracellular Ca2+ concentrations ([Ca2+]i). The results obtained revealed the expression of transcripts of all Kv7 genes, leading to an IKM-like current. Moreover, all tested Kv7 openers inhibited BK- and CAP-induced responses by a similar extent (~60%); at least for BK-induced Ca2+ responses, the potency of retigabine (IC50~1 µM) was higher than that of ICA-27243 (IC50~5 µM) and (S)-1 (IC50~7 µM). Altogether, these results suggest that IKM activation effectively counteracts the cellular processes triggered by TRPV1-mediated pain-inducing stimuli, and highlight a possible critical contribution of Kv7.4 subunits.
Collapse
Affiliation(s)
- Paolo Ambrosino
- Department of Science and Technology, University of Sannio, 82100 Benevento, Italy
| | - Maria Virginia Soldovieri
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, 86100 Campobasso, Italy
| | - Erika Di Zazzo
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, 86100 Campobasso, Italy
| | - Gianluca Paventi
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, 86100 Campobasso, Italy
| | - Fabio Arturo Iannotti
- Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, 80121 Naples, Italy
| | - Ilaria Mosca
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, 86100 Campobasso, Italy
| | - Francesco Miceli
- Division of Pharmacology, Department of Neuroscience, University of Naples "Federico II", 80131 Naples, Italy
| | - Cristina Franco
- Department of Science and Technology, University of Sannio, 82100 Benevento, Italy
| | | | - Maurizio Taglialatela
- Division of Pharmacology, Department of Neuroscience, University of Naples "Federico II", 80131 Naples, Italy.
| |
Collapse
|
20
|
Martinello K, Giacalone E, Migliore M, Brown DA, Shah MM. The subthreshold-active K V7 current regulates neurotransmission by limiting spike-induced Ca 2+ influx in hippocampal mossy fiber synaptic terminals. Commun Biol 2019; 2:145. [PMID: 31044170 PMCID: PMC6486593 DOI: 10.1038/s42003-019-0408-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/29/2019] [Indexed: 12/23/2022] Open
Abstract
Little is known about the properties and function of ion channels that affect synaptic terminal-resting properties. One particular subthreshold-active ion channel, the Kv7 potassium channel, is highly localized to axons, but its role in regulating synaptic terminal intrinsic excitability and release is largely unexplored. Using electrophysiological recordings together with computational modeling, we found that the KV7 current was active at rest in adult hippocampal mossy fiber synaptic terminals and enhanced their membrane conductance. The current also restrained action potential-induced Ca2+ influx via N- and P/Q-type Ca2+ channels in boutons. This was associated with a substantial reduction in the spike half-width and afterdepolarization following presynaptic spikes. Further, by constraining spike-induced Ca2+ influx, the presynaptic KV7 current decreased neurotransmission onto CA3 pyramidal neurons and short-term synaptic plasticity at the mossy fiber-CA3 synapse. This is a distinctive mechanism by which KV7 channels influence hippocampal neuronal excitability and synaptic plasticity.
Collapse
Affiliation(s)
| | | | - Michele Migliore
- Institute of Biophysics, National Research Council, 90146 Palermo, Italy
| | - David A. Brown
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT UK
| | - Mala M. Shah
- UCL School of Pharmacy University College London, London, WC1N 1AX UK
| |
Collapse
|
21
|
de Jong IEM, Jepps TA. Impaired Kv7 channel function in cerebral arteries of a tauopathy mouse model (rTg4510). Physiol Rep 2018; 6:e13920. [PMID: 30548427 PMCID: PMC6289909 DOI: 10.14814/phy2.13920] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/01/2018] [Accepted: 10/18/2018] [Indexed: 01/20/2023] Open
Abstract
In tauopathies, such as Alzheimer's disease with or without concomitant amyloid β plaques, cerebral arteries display pathological remodeling, leading to reduced brain tissue oxygenation and cognitive impairment. The precise mechanisms that underlie this vascular dysfunction remain unclear. Kv7 voltage-dependent K+ channels contribute to the development of myogenic tone in rat cerebral arteries. Thus, we hypothesized that Kv7 channel function would be impaired in the cerebral arteries of a tauopathy mouse model (rTg4510), which might underlie cerebral hypoperfusion associated with the development of neurofibrillary tangles in tauopathies. To test our hypothesis we performed wire myography and quantitative PCR on cerebral arteries, mesenteric arteries and the inferior frontotemporal region of the brain surrounding the middle cerebral artery from tau transgenic mice (rTg4510) and aged-matched controls. We also performed whole-cell patch clamp experiments on HEK293 cells stably expressing Kv7.4. Here, we show that Kv7 channels are functionally impaired in the cerebral arteries of rTg4510 mice, but not in mesenteric arteries from the same mice. The quantitative PCR analysis of the cerebral arteries found no change in the expression of the genes encoding the Kv7 channel α-subunits, however, we found reduced expression of the ancillary subunit, KCNE5 (also termed KCNE1L), in the cerebral arteries of rTg4510 mice. In the brain, rTg4510 mice showed reduced expression of Kv7.3, Kv7.5, and Kv2.1. Co-expression of KCNE5 with Kv7.4 in HEK293 cells produced larger currents at voltages >0 mV and increased the deactivation time for the Kv7.4 channel. Thus, our results demonstrate that Kv7 channel function is attenuated in the cerebral arteries of Tg4510 mice, which may result from decreased KCNE5 expression. Reduced Kv7 channel function might contribute to cerebral hypoperfusion in tauopathies, such as Alzheimer's disease.
Collapse
Affiliation(s)
| | - Thomas A. Jepps
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| |
Collapse
|
22
|
Inagaki A, Hayashi M, Andharia N, Matsuda H. Involvement of butyrate in electrogenic K + secretion in rat rectal colon. Pflugers Arch 2018; 471:313-327. [PMID: 30250967 PMCID: PMC6334752 DOI: 10.1007/s00424-018-2208-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 08/22/2018] [Accepted: 09/13/2018] [Indexed: 12/27/2022]
Abstract
Short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate, are synthesized from dietary carbohydrates by colonic bacterial fermentation. These SCFAs supply energy, suppress cancer, and affect ion transport. However, their roles in ion transport and regulation in the intracellular environment remain unknown. In order to elucidate the roles of SCFAs, we measured short-circuit currents (ISC) and performed RT-PCR and immunohistochemical analyses of ion transporters in rat rectal colon. The application of 30 mM butyrate shifted ISC in a negative direction, but did not attenuate the activity of epithelial Na+ channels (ENaC). The application of bumetanide, a Na+-K+-2Cl− cotransporter inhibitor, to the basolateral side reduced the negative ISC shift induced by butyrate. The application of XE991, a KCNQ-type K+ channel inhibitor, to the apical side decreased the ISC shift induced by butyrate in a dose-dependent manner. The ISC shift was independent of HCO3− and insensitive to ibuprofen, an SMCT1 inhibitor. The mucosa from rat rectal colon expressed mRNAs of H+-coupled monocarboxylate transporters (MCT1, MCT4, and MCT5, also referred to as SLC16A1, SLC16A3, and SLC16A4, respectively). RT-PCR and immunofluorescence analyses demonstrated that KCNQ2 and KCNQ4 localized to the apical membrane of surface cells in rat rectal colon. These results indicate that butyrate, which may be transported by H+-coupled monocarboxylate transporters, activates K+ secretion through KCNQ-type K+ channels on the apical membrane in rat rectal colon. KCNQ-type K+ channels may play a role in intestinal secretion and defense mechanisms in the gastrointestinal tract.
Collapse
Affiliation(s)
- Akihiro Inagaki
- Medical Research Project, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan.
| | - Mikio Hayashi
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan
| | - Naaz Andharia
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan
| | - Hiroko Matsuda
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan
| |
Collapse
|
23
|
Du X, Gao H, Jaffe D, Zhang H, Gamper N. M-type K + channels in peripheral nociceptive pathways. Br J Pharmacol 2018; 175:2158-2172. [PMID: 28800673 PMCID: PMC5980636 DOI: 10.1111/bph.13978] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/17/2017] [Accepted: 08/03/2017] [Indexed: 12/22/2022] Open
Abstract
Pathological pain is a hyperexcitability disorder. Since the excitability of a neuron is set and controlled by a complement of ion channels it expresses, in order to understand and treat pain, we need to develop a mechanistic insight into the key ion channels controlling excitability within the mammalian pain pathways and how these ion channels are regulated and modulated in various physiological and pathophysiological settings. In this review, we will discuss the emerging data on the expression in pain pathways, functional role and modulation of a family of voltage-gated K+ channels called 'M channels' (KCNQ, Kv 7). M channels are increasingly recognized as important players in controlling pain signalling, especially within the peripheral somatosensory system. We will also discuss the therapeutic potential of M channels as analgesic drug targets. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc/.
Collapse
Affiliation(s)
- Xiaona Du
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
| | - Haixia Gao
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeedsUK
| | - David Jaffe
- Department of Biology, UTSA Neurosciences InstituteUniversity of Texas at San AntonioSan AntonioTXUSA
| | - Hailin Zhang
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
| | - Nikita Gamper
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeedsUK
| |
Collapse
|
24
|
Parrilla-Carrero J, Buchta WC, Goswamee P, Culver O, McKendrick G, Harlan B, Moutal A, Penrod R, Lauer A, Ramakrishnan V, Khanna R, Kalivas P, Riegel AC. Restoration of Kv7 Channel-Mediated Inhibition Reduces Cued-Reinstatement of Cocaine Seeking. J Neurosci 2018; 38:4212-4229. [PMID: 29636392 PMCID: PMC5963852 DOI: 10.1523/jneurosci.2767-17.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 12/16/2022] Open
Abstract
Cocaine addicts display increased sensitivity to drug-associated cues, due in part to changes in the prelimbic prefrontal cortex (PL-PFC). The cellular mechanisms underlying cue-induced reinstatement of cocaine seeking remain unknown. Reinforcement learning for addictive drugs may produce persistent maladaptations in intrinsic excitability within sparse subsets of PFC pyramidal neurons. Using a model of relapse in male rats, we sampled >600 neurons to examine spike frequency adaptation (SFA) and afterhyperpolarizations (AHPs), two systems that attenuate low-frequency inputs to regulate neuronal synchronization. We observed that training to self-administer cocaine or nondrug (sucrose) reinforcers decreased SFA and AHPs in a subpopulation of PL-PFC neurons. Only with cocaine did the resulting hyperexcitability persist through extinction training and increase during reinstatement. In neurons with intact SFA, dopamine enhanced excitability by inhibiting Kv7 potassium channels that mediate SFA. However, dopamine effects were occluded in neurons from cocaine-experienced rats, where SFA and AHPs were reduced. Pharmacological stabilization of Kv7 channels with retigabine restored SFA and Kv7 channel function in neuroadapted cells. When microinjected bilaterally into the PL-PFC 10 min before reinstatement testing, retigabine reduced cue-induced reinstatement of cocaine seeking. Last, using cFos-GFP transgenic rats, we found that the loss of SFA correlated with the expression of cFos-GFP following both extinction and re-exposure to drug-associated cues. Together, these data suggest that cocaine self-administration desensitizes inhibitory Kv7 channels in a subpopulation of PL-PFC neurons. This subpopulation of neurons may represent a persistent neural ensemble responsible for driving drug seeking in response to cues.SIGNIFICANCE STATEMENT Long after the cessation of drug use, cues associated with cocaine still elicit drug-seeking behavior, in part by activation of the prelimbic prefrontal cortex (PL-PFC). The underlying cellular mechanisms governing these activated neurons remain unclear. Using a rat model of relapse to cocaine seeking, we identified a population of PL-PFC neurons that become hyperexcitable following chronic cocaine self-administration. These neurons show persistent loss of spike frequency adaptation, reduced afterhyperpolarizations, decreased sensitivity to dopamine, and reduced Kv7 channel-mediated inhibition. Stabilization of Kv7 channel function with retigabine normalized neuronal excitability, restored Kv7 channel currents, and reduced drug-seeking behavior when administered into the PL-PFC before reinstatement. These data highlight a persistent adaptation in a subset of PL-PFC neurons that may contribute to relapse vulnerability.
Collapse
Affiliation(s)
- Jeffrey Parrilla-Carrero
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - William C Buchta
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Priyodarshan Goswamee
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Oliver Culver
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Greer McKendrick
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Benjamin Harlan
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Aubin Moutal
- Department of Pharmacology, University of Arizona, Tucson, Arizona 85724, and
| | - Rachel Penrod
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Abigail Lauer
- Department of Public Health Sciences., Medical University of South Carolina, Charleston, SC 29425
| | - Viswanathan Ramakrishnan
- Department of Public Health Sciences., Medical University of South Carolina, Charleston, SC 29425
| | - Rajesh Khanna
- Department of Pharmacology, University of Arizona, Tucson, Arizona 85724, and
| | - Peter Kalivas
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Arthur C Riegel
- Department of Neuroscience,
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| |
Collapse
|
25
|
Wei X, Zhang Y, Yin B, Wen J, Cheng J, Fu X. The expression and function of KCNQ potassium channels in human chorionic plate arteries from women with normal pregnancies and pre-eclampsia. PLoS One 2018; 13:e0192122. [PMID: 29579054 PMCID: PMC5868761 DOI: 10.1371/journal.pone.0192122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 01/18/2018] [Indexed: 11/25/2022] Open
Abstract
Pre-eclampsia is associated with altered maternal and placental vascular reactivity. Kv7 channels (encoded by KCNQ 1–5 genes) are a potential contributor to the regulation of vascular tone in CPAs (chorionic plate arteries) during normal pregnancy. The aim of this study is to establish the expression profile of KCNQ subunits in CPAs taken from women with preeclampsia or normotensive women and to examine the functional relevance of the Kv7 channels on an altered expression profile of KCNQ subunits. The effects of Kv7 channel modulators on CPAs were investigated by tension measurement. Quantitative PCR experiments were used to analyze the expression of KCNQ genes. Western blotting and immunofluorescence were both used to analyze the protein expression of Kv7 channels. Finally, in CPAs from normotensive women, the Kv7 channel blocker XE991 increased arterial basal tone and U46619-induced contraction, and pre-contracted CPAs (10−7 M U46619) exhibited significant relaxation following treatment with Retigabine(Kv7.2–7.5 activator) and BMS-204352(Kv7.2–7.5 activator). However, ICA-27243(selective KCNQ2 and KCNQ3 activator) and ML277(selective KV7.1 activator) had no significant effect on tension in the pre-contracted CPAs. Conversely, compared with CPAs from normotensive women, the effects of XE991 on basal tone and agonist (U46619)-induced contractions in CPAs from women with preeclampsia were markedly attenuated. Moreover, the relaxation effects of Retigabine and BMS-204352 on pre-contracted CPA vessels from women with pre-eclampsia were also markedly down-regulated. Interestingly, the relaxation ability of ICA-27243 in pre-contracted CPA vessels in women with pre-eclampsia was enhanced. The mRNA of KCNQ3 was specifically up-regulated, whereas those for KCNQ4 and KCNQ5 were down-regulated in CPAs from women with pre-eclampsia compared with those in normotensive women. Similar observations were found in a subsequent analysis of protein expression of KCNQ genes 3–5. Thus, down-regulated Kv7 channel function in tension regulation of CPAs in women with pre-eclampsia could be associated with considerably altered expression profiles of Kv7 subunits.
Collapse
Affiliation(s)
- Xiaohong Wei
- Department of Gynecology and Obstetrics, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Yujiao Zhang
- Department of Gynecology and Obstetrics, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Benlan Yin
- Department of Gynecology and Obstetrics, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Jing Wen
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Jun Cheng
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Xiaodong Fu
- Department of Gynecology and Obstetrics, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
- * E-mail:
| |
Collapse
|
26
|
Lee C, Jones TA. Acute blockade of inner ear marginal and dark cell K + secretion: Effects on gravity receptor function. Hear Res 2018; 361:152-156. [PMID: 29459166 DOI: 10.1016/j.heares.2018.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 12/13/2017] [Accepted: 02/09/2018] [Indexed: 11/18/2022]
Abstract
Specific pharmacological blockade of KCNQ (Kv7) channels with XE991 rapidly (within 20 min) and profoundly alters inner ear gravity receptor responses to head motion (Lee et al., 2017). We hypothesized that these effects were attributable to the suppression of K+ secretion following blockade of KCNQ1-KCNE1 channels in vestibular dark cells and marginal cells. To test this hypothesis, K+ secretion was independently inhibited by blocking the Na+-K+-2Cl- cotransporter (NKCC1, Slc12a2) rather than KCNQ1-KCNE1 channels. Acute blockade of NKCC1 with ethacrynic acid (40 mg/kg) eliminated auditory responses (ABRs) within approximately 70 min of injection, but had no effect on vestibular gravity receptor function (VsEPs) over a period of 2 h in the same animals. These findings show that, vestibular gravity receptors are highly resistant to acute disruption of endolymph secretion unlike the auditory system. Based on this we argue that acute suppression of K+ secretion alone does not likely account for the rapid profound effects of XE991 on gravity receptors. Instead the effects of XE991 likely require additional action at KCNQ channels located within the sensory epithelium itself.
Collapse
Affiliation(s)
- Choongheon Lee
- University of Nebraska-Lincoln, Department of Special Education and Communication Disorders, Lincoln, NE 68583-0738, USA.
| | - Timothy A Jones
- University of Nebraska-Lincoln, Department of Special Education and Communication Disorders, Lincoln, NE 68583-0738, USA.
| |
Collapse
|
27
|
Ocorr K, Zambon A, Nudell Y, Pineda S, Diop S, Tang M, Akasaka T, Taylor E. Age-dependent electrical and morphological remodeling of the Drosophila heart caused by hERG/seizure mutations. PLoS Genet 2017; 13:e1006786. [PMID: 28542428 PMCID: PMC5459509 DOI: 10.1371/journal.pgen.1006786] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 06/05/2017] [Accepted: 04/30/2017] [Indexed: 12/03/2022] Open
Abstract
Understanding the cellular-molecular substrates of heart disease is key to the development of cardiac specific therapies and to the prevention of off-target effects by non-cardiac targeted drugs. One of the primary targets for therapeutic intervention has been the human ether a go-go (hERG) K+ channel that, together with the KCNQ channel, controls the rate and efficiency of repolarization in human myocardial cells. Neither of these channels plays a major role in adult mouse heart function; however, we show here that the hERG homolog seizure (sei), along with KCNQ, both contribute significantly to adult heart function as they do in humans. In Drosophila, mutations in or cardiac knockdown of sei channels cause arrhythmias that become progressively more severe with age. Intracellular recordings of semi-intact heart preparations revealed that these perturbations also cause electrical remodeling that is reminiscent of the early afterdepolarizations seen in human myocardial cells defective in these channels. In contrast to KCNQ, however, mutations in sei also cause extensive structural remodeling of the myofibrillar organization, which suggests that hERG channel function has a novel link to sarcomeric and myofibrillar integrity. We conclude that deficiency of ion channels with similar electrical functions in cardiomyocytes can lead to different types or extents of electrical and/or structural remodeling impacting cardiac output. We have used the fruit fly cardiac model to show that seizure, the fly homolog of the human ether a go-go K+ channel hERG, is functional in the fly heart. This channel plays a major role in cardiac repolarization in humans but not in adult rodent hearts. Loss of channel function in the fly causes bradycardia, electrical arrhythmia and altered myofibrillar structure. Gene expression analysis indicates that Wnt signaling is affected and we show a genetic interaction between sei and pygopus, a Wnt pathway component, on heart function.
Collapse
Affiliation(s)
- Karen Ocorr
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, United States of America
- * E-mail:
| | - Alexander Zambon
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, United States of America
| | - Yoav Nudell
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, United States of America
| | - Santiago Pineda
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, United States of America
| | - Soda Diop
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, United States of America
| | - Min Tang
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, United States of America
| | - Takeshi Akasaka
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, United States of America
| | - Erika Taylor
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, United States of America
| |
Collapse
|
28
|
Abstract
Neuronal Kv7 channels underlie a voltage-gated non-inactivating potassium current known as the M-current. Due to its particular characteristics, Kv7 channels show pronounced control over the excitability of neurons. We will discuss various factors that have been shown to drastically alter the activity of this channel such as protein and phospholipid interactions, phosphorylation, calcium, and numerous neurotransmitters. Kv7 channels locate to key areas for the control of action potential initiation and propagation. Moreover, we will explore the dynamic surface expression of the channel modulated by neurotransmitters and neural activity. We will also focus on known principle functions of neural Kv7 channels: control of resting membrane potential and spiking threshold, setting the firing frequency, afterhyperpolarization after burst firing, theta resonance, and transient hyperexcitability from neurotransmitter-induced suppression of the M-current. Finally, we will discuss the contribution of altered Kv7 activity to pathologies such as epilepsy and cognitive deficits.
Collapse
Affiliation(s)
- Derek L Greene
- Department of Pharmacology, University of California, 360 Med Surge II, Irvine, CA, 92697, USA
| | - Naoto Hoshi
- Department of Pharmacology, University of California, 360 Med Surge II, Irvine, CA, 92697, USA.
- Department of Physiology and Biophysics, University of California, Irvine, USA.
| |
Collapse
|
29
|
Chen X, Li W, Hiett SC, Obukhov AG. Novel Roles for Kv7 Channels in Shaping Histamine-Induced Contractions and Bradykinin-Dependent Relaxations in Pig Coronary Arteries. PLoS One 2016; 11:e0148569. [PMID: 26844882 PMCID: PMC4742238 DOI: 10.1371/journal.pone.0148569] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/08/2016] [Indexed: 12/22/2022] Open
Abstract
Voltage-gated Kv7 channels are inhibited by agonists of Gq-protein-coupled receptors, such as histamine. Recent works have provided evidence that inhibition of vascular Kv7 channels may trigger vessel contractions. In this study, we investigated how Kv7 activity modulates the histamine-induced contractions in "healthy" and metabolic syndrome (MetS) pig right coronary arteries (CAs). We performed isometric tension and immunohistochemical studies with domestic, lean Ossabaw, and MetS Ossabaw pig CAs. We found that neither the Kv7.2/Kv7.4/Kv7.5 activator ML213 nor the general Kv7 inhibitor XE991 altered the tension of CA rings under preload, indicating that vascular Kv7 channels are likely inactive in the preloaded rings. Conversely, ML213 potently dilated histamine-pre-contracted CAs, suggesting that Kv7 channels are activated during histamine applications and yet partially inhibited by histamine. Immunohistochemistry analysis revealed strong Kv7.4 immunostaining in the medial and intimal layers of the CA wall, whereas Kv7.5 immunostaining intensity was strong in the intimal but weak in the medial layers. The medial Kv7 immunostaining was significantly weaker in MetS Ossabaw CAs as compared to lean Ossabaw or domestic CAs. Consistently, histamine-pre-contracted MetS Ossabaw CAs exhibited attenuated ML213-dependent dilations. In domestic pig CAs, where medial Kv7 immunostaining intensity was stronger, histamine-induced contractions spontaneously decayed to ~31% of the peak amplitude within 4 minutes. Oppositely, in Ossabaw CAs, where Kv7 immunostaining intensity was weaker, the histamine-induced contractions were more sustained. XE991 pretreatment significantly slowed the decay rate of histamine-induced contractions in domestic CAs, supporting the hypothesis that increased Kv7 activity correlates with a faster rate of histamine-induced contraction decay. Alternatively, XE991 significantly decreased the amplitude of bradykinin-dependent dilations in pre-contracted CAs. We propose that in CAs, a decreased expression or a loss of function of Kv7 channels may lead to sustained histamine-induced contractions and reduced endothelium-dependent relaxation, both risk factors for coronary spasm.
Collapse
Affiliation(s)
- Xingjuan Chen
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine - Indianapolis, Indianapolis, Indiana, 46202, United States of America
| | - Wennan Li
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine - Indianapolis, Indianapolis, Indiana, 46202, United States of America
| | - S. Christopher Hiett
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine - Indianapolis, Indianapolis, Indiana, 46202, United States of America
| | - Alexander G. Obukhov
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine - Indianapolis, Indianapolis, Indiana, 46202, United States of America
- * E-mail:
| |
Collapse
|
30
|
Choveau FS, Zhang J, Bierbower SM, Sharma R, Shapiro MS. The Role of the Carboxyl Terminus Helix C-D Linker in Regulating KCNQ3 K+ Current Amplitudes by Controlling Channel Trafficking. PLoS One 2015; 10:e0145367. [PMID: 26692086 PMCID: PMC4687061 DOI: 10.1371/journal.pone.0145367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/01/2015] [Indexed: 12/18/2022] Open
Abstract
In the central and peripheral nervous system, the assembly of KCNQ3 with KCNQ2 as mostly heteromers, but also homomers, underlies “M-type” currents, a slowly-activating voltage-gated K+ current that plays a dominant role in neuronal excitability. KCNQ3 homomers yield much smaller currents compared to KCNQ2 or KCNQ4 homomers and KCNQ2/3 heteromers. This smaller current has been suggested to result either from divergent channel surface expression or from a pore that is more unstable in KCNQ3. Channel surface expression has been shown to be governed by the distal part of the C-terminus in which helices C and D are critical for channel trafficking and assembly. A sequence alignment of this region in KCNQ channels shows that KCNQ3 possesses a longer linker between helix C and D compared to the other KCNQ subunits. Here, we investigate the role of the extra residues of this linker on KCNQ channel expression. Deletion of these residues increased KCNQ3 current amplitudes. Total internal reflection fluorescence imaging and plasma membrane protein assays suggest that the increase in current is due to a higher surface expression of the channels. Conversely, introduction of the extra residues into the linker between helices C and D of KCNQ4 reduced current amplitudes by decreasing the number of KCNQ4 channels at the plasma membrane. Confocal imaging suggests a higher fraction of channels, which possess the extra residues of helix C-D linker, were retained within the endoplasmic reticulum. Such retention does not appear to lead to protein accumulation and activation of the unfolded protein response that regulates protein folding and maintains endoplasmic reticulum homeostasis. Taken together, we conclude that extra helix C-D linker residues play a role in KCNQ3 current amplitudes by controlling the exit of the channel from the endoplasmic reticulum.
Collapse
Affiliation(s)
- Frank S. Choveau
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Jie Zhang
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Sonya M. Bierbower
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Ramaswamy Sharma
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Mark S. Shapiro
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
| |
Collapse
|
31
|
Mills TA, Greenwood SL, Devlin G, Shweikh Y, Robinson M, Cowley E, Hayward CE, Cottrell EC, Tropea T, Brereton MF, Dalby-Brown W, Wareing M. Activation of KV7 channels stimulates vasodilatation of human placental chorionic plate arteries. Placenta 2015; 36:638-44. [PMID: 25862611 DOI: 10.1016/j.placenta.2015.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/12/2015] [Accepted: 03/14/2015] [Indexed: 02/01/2023]
Abstract
INTRODUCTION Potassium (K(+)) channels are key regulators of vascular smooth muscle cell (VSMC) excitability. In systemic small arteries, Kv7 channel expression/activity has been noted and a role in vascular tone regulation demonstrated. We aimed to demonstrate functional Kv7 channels in human fetoplacental small arteries. METHODS Human placental chorionic plate arteries (CPAs) were obtained at term. CPA responses to Kv7 channel modulators was determined by wire myography. Presence of Kv7 channel mRNA (encoded by KCNQ1-5) and protein expression were assessed by RT-PCR and immunohistochemistry/immunofluorescence, respectively. RESULTS Kv7 channel blockade with linopirdine increased CPA basal tone and AVP-induced contraction. Pre-contracted CPAs (AVP; 80 mM K(+) depolarization solution) exhibited significant relaxation to flupirtine, retigabine, the acrylamide (S)-1, and (S) BMS-204352, differential activators of Kv7.1 - Kv7.5 channels. All CPAs assessed expressed KCNQ1 and KCNQ3-5 mRNA; KCNQ2 was expressed only in a subset of CPAs. Kv7 protein expression was confirmed in intact CPAs and isolated VSMCs. DISCUSSION Kv7 channels are present and active in fetoplacental vessels, contributing to vascular tone regulation in normal pregnancy. Targeting these channels may represent a therapeutic intervention in pregnancies complicated by increased vascular resistance.
Collapse
Affiliation(s)
- T A Mills
- School of Nursing, Midwifery and Social Work, The University of Manchester, Jean McFarlane Building, Oxford Road, Manchester M13 9PL, United Kingdom.
| | - S L Greenwood
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - G Devlin
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - Y Shweikh
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom
| | - M Robinson
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom
| | - E Cowley
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - C E Hayward
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - E C Cottrell
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - T Tropea
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom; Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, CS, Italy.
| | - M F Brereton
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - W Dalby-Brown
- Pcovery Aps, Thorvaldsensvej 57, DK-1871 Frederiksberg C, Denmark.
| | - M Wareing
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| |
Collapse
|
32
|
Svalø J, Sheykhzade M, Nordling J, Matras C, Bouchelouche P. Functional and molecular evidence for Kv7 channel subtypes in human detrusor from patients with and without bladder outflow obstruction. PLoS One 2015; 10:e0117350. [PMID: 25692982 PMCID: PMC4333569 DOI: 10.1371/journal.pone.0117350] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 12/21/2014] [Indexed: 12/30/2022] Open
Abstract
The aim of the study was to investigate whether Kv7 channels and their ancillary β-subunits, KCNE, are functionally expressed in the human urinary bladder. Kv7 channels were examined at the molecular level and by functional studies using RT-qPCR and myography, respectively. We found mRNA expression of KCNQ1, KCNQ3-KCNQ5 and KCNE1-5 in the human urinary bladder from patients with normal bladder function (n = 7) and in patients with bladder outflow obstruction (n = 3). Interestingly, a 3.4-fold up-regulation of KCNQ1 was observed in the latter. The Kv7 channel subtype selective modulators, ML277 (activator of Kv7.1 channels, 10 μM) and ML213 (activator of Kv7.2, Kv7.4, Kv7.4/7.5 and Kv7.5 channels, 10 μM), reduced the tone of 1 μM carbachol pre-constricted bladder strips. XE991 (blocker of Kv7.1-7.5 channels, 10 μM) had opposing effects as it increased contractions achieved with 20 mM KPSS. Furthermore, we investigated if there is interplay between Kv7 channels and β-adrenoceptors. Using cumulative additions of isoprenaline (β-adrenoceptor agonist) and forskolin (adenylyl cyclase activator) in combination with the Kv7 channel activator and blocker, retigabine and XE991, we did not find interplay between Kv7 channels and β-adrenoceptors in the human urinary bladder. The performed gene expression analysis combined with the organ bath studies imply that compounds that activate Kv7 channels could be useful for treatment of overactive bladder syndrome.
Collapse
Affiliation(s)
- Julie Svalø
- Smooth Muscle Research Center, Department of Clinical Biochemistry, Copenhagen University Hospital, Koege, Denmark
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| | - Majid Sheykhzade
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Nordling
- Department of Urology, Copenhagen University Hospital, Herlev, Denmark
| | - Christina Matras
- Department of Urology, Copenhagen University Hospital, Naestved, Denmark
| | - Pierre Bouchelouche
- Smooth Muscle Research Center, Department of Clinical Biochemistry, Copenhagen University Hospital, Koege, Denmark
| |
Collapse
|
33
|
Tong WC, Tribe RM, Smith R, Taggart MJ. Computational modeling reveals key contributions of KCNQ and hERG currents to the malleability of uterine action potentials underpinning labor. PLoS One 2014; 9:e114034. [PMID: 25474527 PMCID: PMC4256391 DOI: 10.1371/journal.pone.0114034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 11/03/2014] [Indexed: 11/19/2022] Open
Abstract
The electrical excitability of uterine smooth muscle cells is a key determinant of the contraction of the organ during labor and is manifested by spontaneous, periodic action potentials (APs). Near the end of term, APs vary in shape and size reflecting an ability to change the frequency, duration and amplitude of uterine contractions. A recent mathematical model quantified several ionic features of the electrical excitability in uterine smooth muscle cells. It replicated many of the experimentally recorded uterine AP configurations but its limitations were evident when trying to simulate the long-duration bursting APs characteristic of labor. A computational parameter search suggested that delayed rectifying K(+) currents could be a key model component requiring improvement to produce the longer-lasting bursting APs. Of the delayed rectifying K(+) currents family it is of interest that KCNQ and hERG channels have been reported to be gestationally regulated in the uterus. These currents exhibit features similar to the broadly defined uterine IK1 of the original mathematical model. We thus formulated new quantitative descriptions for several I(KCNQ) and I(hERG). Incorporation of these currents into the uterine cell model enabled simulations of the long-lasting bursting APs. Moreover, we used this modified model to simulate the effects of different contributions of I(KCNQ) and I(hERG) on AP form. Our findings suggest that the alterations in expression of hERG and KCNQ channels can potentially provide a mechanism for fine tuning of AP forms that lends a malleability for changing between plateau-like and long-lasting bursting-type APs as uterine cells prepare for parturition.
Collapse
Affiliation(s)
- Wing-Chiu Tong
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Rachel M. Tribe
- Division of Women's Health, King's College London and King's Health Partners, London, United Kingdom
| | - Roger Smith
- Hunter Medical Research Institute, University of Newcastle, New Lambton, New South Wales, Australia
| | - Michael J. Taggart
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| |
Collapse
|
34
|
Yuan Y, Isom LL. SUMOylation of Neuronal K⁺ channels: a potential therapeutic pathway for epilepsy and SUDEP? Neuron 2014; 83:996-8. [PMID: 25189206 DOI: 10.1016/j.neuron.2014.08.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Critical unmet clinical needs are the treatment of epilepsy without side effects and prevention of sudden unexpected death in epilepsy, or SUDEP. In this issue of Neuron, Qi et al. (2014), define how hyper-SUMOylation impacts K(+) channel activity in vivo and could serve as a potential pathway for development of novel epilepsy therapeutics.
Collapse
Affiliation(s)
- Yukun Yuan
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| |
Collapse
|
35
|
Blom SM, Rottländer M, Kehler J, Bundgaard C, Schmitt N, Jensen HS. From pan-reactive KV7 channel opener to subtype selective opener/inhibitor by addition of a methyl group. PLoS One 2014; 9:e100209. [PMID: 24956197 PMCID: PMC4067310 DOI: 10.1371/journal.pone.0100209] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/22/2014] [Indexed: 01/24/2023] Open
Abstract
The voltage-gated potassium channels of the KV7 family (KV7.1–5) play important roles in controlling neuronal excitability and are therefore attractive targets for treatment of CNS disorders linked to hyperexcitability. One of the main challenges in developing KV7 channel active drugs has been to identify compounds capable of discriminating between the neuronally expressed subtypes (KV7.2–5), aiding the identification of the subunit composition of KV7 currents in various tissues, and possessing better therapeutic potential for particular indications. By taking advantage of the structure-activity relationship of acrylamide KV7 channel openers and the effects of these compounds on mutant KV7 channels, we have designed and synthesized a novel KV7 channel modulator with a unique profile. The compound, named SMB-1, is an inhibitor of KV7.2 and an activator of KV7.4. SMB-1 inhibits KV7.2 by reducing the current amplitude and increasing the time constant for the slow component of the activation kinetics. The activation of KV7.4 is seen as an increase in the current amplitude and a slowing of the deactivation kinetics. Experiments studying mutant channels with a compromised binding site for the KV7.2–5 opener retigabine indicate that SMB-1 binds within the same pocket as retigabine for both inhibition of KV7.2 and activation of KV7.4. SMB-1 may serve as a valuable tool for KV7 channel research and may be used as a template for further design of better subtype selective KV7 channel modulators. A compound with this profile could hold novel therapeutic potential such as the treatment of both positive and cognitive symptoms in schizophrenia.
Collapse
Affiliation(s)
- Sigrid Marie Blom
- Division of Neuroscience Drug Discovery, H. Lundbeck A/S, Copenhagen, Denmark
- Department of Biomedical Sciences and Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mario Rottländer
- Division of Discovery Chemistry and DMPK, H. Lundbeck A/S, Copenhagen, Denmark
| | - Jan Kehler
- Division of Discovery Chemistry and DMPK, H. Lundbeck A/S, Copenhagen, Denmark
| | | | - Nicole Schmitt
- Department of Biomedical Sciences and Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Sindal Jensen
- Division of Neuroscience Drug Discovery, H. Lundbeck A/S, Copenhagen, Denmark
- * E-mail:
| |
Collapse
|
36
|
Dettling J, Franz C, Zimmermann U, Lee SC, Bress A, Brandt N, Feil R, Pfister M, Engel J, Flamant F, Rüttiger L, Knipper M. Autonomous functions of murine thyroid hormone receptor TRα and TRβ in cochlear hair cells. Mol Cell Endocrinol 2014; 382:26-37. [PMID: 24012852 DOI: 10.1016/j.mce.2013.08.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 08/22/2013] [Accepted: 08/29/2013] [Indexed: 11/18/2022]
Abstract
Thyroid hormone acts on gene transcription by binding to its nuclear receptors TRα1 and TRβ. Whereas global deletion of TRβ causes deafness, global TRα-deficient mice have normal hearing thresholds. Since the individual roles of the two receptors in cochlear hair cells are still unclear, we generated mice with a hair cell-specific mutation of TRα1 or deletion of TRβ using the Cre-loxP system. Hair cell-specific TRβ mutant mice showed normal hearing thresholds but delayed BK channel expression in inner hair cells, slightly stronger outer hair cell function, and slightly reduced amplitudes of auditory brainstem responses. In contrast, hair cell-specific TRα mutant mice showed normal timing of BK channel expression, slightly reduced outer hair cell function, and slightly enhanced amplitudes of auditory brainstem responses. Our data demonstrate that TRβ-related deafness originates outside of hair cells and that TRα and TRβ play opposing, non-redundant roles in hair cells. A role for thyroid hormone receptors in controlling key regulators that shape signal transduction during development is discussed. Thyroid hormone may act through different thyroid hormone receptor activities to permanently alter the sensitivity of auditory neurotransmission.
Collapse
Affiliation(s)
- Juliane Dettling
- Molecular Physiology of Hearing, Hearing Research Centre Tübingen (THRC), Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany
| | - Christoph Franz
- Molecular Physiology of Hearing, Hearing Research Centre Tübingen (THRC), Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany
| | - Ulrike Zimmermann
- Molecular Physiology of Hearing, Hearing Research Centre Tübingen (THRC), Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany
| | - Sze Chim Lee
- Molecular Physiology of Hearing, Hearing Research Centre Tübingen (THRC), Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany
| | - Andreas Bress
- Molecular Genetics, THRC, Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany
| | - Niels Brandt
- Department of Biophysics, Saarland University, 66421 Homburg/Saar, Germany
| | - Robert Feil
- Department of Signal Transduction & Transgenic Models, Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
| | - Markus Pfister
- Molecular Genetics, THRC, Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany
| | - Jutta Engel
- Department of Biophysics, Saarland University, 66421 Homburg/Saar, Germany
| | - Frédéric Flamant
- Institut de Génomique Fonctionnelle, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon cedex 07, Lyon, France
| | - Lukas Rüttiger
- Molecular Physiology of Hearing, Hearing Research Centre Tübingen (THRC), Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany
| | - Marlies Knipper
- Molecular Physiology of Hearing, Hearing Research Centre Tübingen (THRC), Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany.
| |
Collapse
|
37
|
Grunnet M, Strøbæk D, Hougaard C, Christophersen P. Kv7 channels as targets for anti-epileptic and psychiatric drug-development. Eur J Pharmacol 2014; 726:133-7. [PMID: 24457124 DOI: 10.1016/j.ejphar.2014.01.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/16/2013] [Accepted: 01/06/2014] [Indexed: 11/18/2022]
Abstract
The Kv7 channels, a family of voltage-dependent K(+) channels (Kv7.1-Kv7.5), have gained much attention in drug discovery especially because four members are genetically linked to diseases. For disorders of the CNS focus was originally on epilepsy and pain, but it is becoming increasingly evident that Kv7 channels can also be valid targets for psychiatric disorders, such as anxiety and mania. The common denominator is probably neuronal hyperexcitability in different brain areas, which can be successfully attenuated by pharmacological increment of Kv7 channel activity. This perspective attempts to review the current status and challenges for CNS drug discovery based on Kv7 channels as targets for neurological and psychiatric indications with special focus on selectivity and mode-of-actions.
Collapse
Affiliation(s)
- Morten Grunnet
- Lundbeck Pharma A/S, Ottiliavej 9 Valby, DK2500, Denmark
| | - Dorte Strøbæk
- Aniona Aps, Baltorpvej 154, Ballerup DK2750, Denmark
| | | | | |
Collapse
|
38
|
Lee BH, Ryu PD, Lee SY. Serum starvation-induced voltage-gated potassium channel Kv7.5 expression and its regulation by Sp1 in canine osteosarcoma cells. Int J Mol Sci 2014; 15:977-93. [PMID: 24434641 PMCID: PMC3907850 DOI: 10.3390/ijms15010977] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 12/20/2013] [Accepted: 12/30/2013] [Indexed: 01/03/2023] Open
Abstract
The KCNQ gene family, whose members encode Kv7 channels, belongs to the voltage-gated potassium (Kv) channel group. The roles of this gene family have been widely investigated in nerve and muscle cells. In the present study, we investigated several characteristics of Kv7.5, which is strongly expressed in the canine osteosarcoma cell line, CCL-183. Serum starvation upregulated Kv7.5 expression, and the Kv7 channel opener, flupirtine, attenuated cell proliferation by arresting cells in the G0/G1 phase. We also showed that Kv7.5 knockdown helps CCL-183 cells to proliferate. In an effort to find an endogenous regulator of Kv7.5, we used mithramycin A to reduce the level of the transcription factor Sp1, and it strongly inhibited the induction of Kv7.5 in CCL-183 cells. These results suggest that the activation of Kv7.5 by flupirtine may exert an anti-proliferative effect in canine osteosarcoma. Therefore, Kv7.5 is a possible molecular target for canine osteosarcoma therapy.
Collapse
Affiliation(s)
- Bo Hyung Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| |
Collapse
|
39
|
Khanamiri S, Soltysinska E, Jepps TA, Bentzen BH, Chadha PS, Schmitt N, Greenwood IA, Olesen SP. Contribution of Kv7 channels to basal coronary flow and active response to ischemia. Hypertension 2013; 62:1090-7. [PMID: 24082059 DOI: 10.1161/hypertensionaha.113.01244] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The goal of the present study was to determine the role of KCNQ-encoded Kv channels (Kv7 channels) in the passive and active regulation of coronary flow in normotensive and hypertensive rats. In left anterior descending coronary arteries from normotensive rats, structurally different Kv7.2 to 7.5 activators produced relaxations, which were considerably less in arteries from hypertensive rats and were not mimicked by the Kv7.1-specific activator R-L3. In isolated, perfused heart preparations, coronary flow rate increased in response to the Kv7.2 to 7.5 activator (S)-1 and was diminished in the presence of a Kv7 inhibitor. The expression levels of KCNQ1-5 and their known accessory KCNE1-5 subunits in coronary arteries were similar in normotensive and hypertensive rats as measured by quantitative polymerase chain reaction. However, Kv7.4 protein expression was reduced in hypertensive rats. Application of adenosine or A2A receptor agonist CGS-21680 produced concentration-dependent relaxations of coronary arteries from normotensive rats, which were attenuated by application of Kv7 inhibitors. Kv7 blockers also attenuated the ischemia-induced increase in coronary perfusion in Langendorff studies. Overall, these data establish Kv7 channels as crucial regulators of coronary flow at resting and after hypoxic insult.
Collapse
Affiliation(s)
- Saereh Khanamiri
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Danish National Research Foundation Centre for Cardiac Arrhythmia, The Panum Institute, University of Copenhagen, 12.5.14, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Afeli SAY, Malysz J, Petkov GV. Molecular expression and pharmacological evidence for a functional role of kv7 channel subtypes in Guinea pig urinary bladder smooth muscle. PLoS One 2013; 8:e75875. [PMID: 24073284 PMCID: PMC3779188 DOI: 10.1371/journal.pone.0075875] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 08/19/2013] [Indexed: 12/30/2022] Open
Abstract
Voltage-gated Kv7 (KCNQ) channels are emerging as essential regulators of smooth muscle excitability and contractility. However, their physiological role in detrusor smooth muscle (DSM) remains to be elucidated. Here, we explored the molecular expression and function of Kv7 channel subtypes in guinea pig DSM by RT-PCR, qRT-PCR, immunohistochemistry, electrophysiology, and isometric tension recordings. In whole DSM tissue, mRNAs for all Kv7 channel subtypes were detected in a rank order: Kv7.1~Kv7.2Kv7.3~Kv7.5Kv7.4. In contrast, freshly-isolated DSM cells showed mRNA expression of: Kv7.1~Kv7.2Kv7.5Kv7.3~Kv7.4. Immunohistochemical confocal microscopy analyses of DSM, conducted by using co-labeling of Kv7 channel subtype-specific antibodies and α-smooth muscle actin, detected protein expression for all Kv7 channel subtypes, except for the Kv7.4, in DSM cells. L-364373 (R-L3), a Kv7.1 channel activator, and retigabine, a Kv7.2-7.5 channel activator, inhibited spontaneous phasic contractions and the 10-Hz electrical field stimulation (EFS)-induced contractions of DSM isolated strips. Linopiridine and XE991, two pan-Kv7 (effective at Kv7.1-Kv7.5 subtypes) channel inhibitors, had opposite effects increasing DSM spontaneous phasic and 10 Hz EFS-induced contractions. EFS-induced DSM contractions generated by a wide range of stimulation frequencies were decreased by L-364373 (10 µM) or retigabine (10 µM), and increased by XE991 (10 µM). Retigabine (10 µM) induced hyperpolarization and inhibited spontaneous action potentials in freshly-isolated DSM cells. In summary, Kv7 channel subtypes are expressed at mRNA and protein levels in guinea pig DSM cells. Their pharmacological modulation can control DSM contractility and excitability; therefore, Kv7 channel subtypes provide potential novel therapeutic targets for urinary bladder dysfunction.
Collapse
Affiliation(s)
- Serge A. Y. Afeli
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina, United States of America
| | - John Malysz
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina, United States of America
| | - Georgi V. Petkov
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina, United States of America
- * E-mail:
| |
Collapse
|
41
|
Huang CW, Hung TY, Liao YK, Hsu MC, Wu SN. Underlying mechanism of regulatory actions of diclofenac, a nonsteroidal anti-inflammatory agent, on neuronal potassium channels and firing: an experimental and theoretical study. J Physiol Pharmacol 2013; 64:269-280. [PMID: 23959723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 06/27/2013] [Indexed: 06/02/2023]
Abstract
Diclofenac (DIC), a nonsteroidal anti-inflammatory drug, is known to exert anti-nociceptive and anti-convulsant actions; however, its effects on ion currents, in neurons remain debatable. We aimed to investigate (1) potential effects of diclofenac on membrane potential and potassium currents in differentiated NSC-34 neuronal cells and dorsal root ganglion (DRG) neurons with whole-cell patch-clamp technology, and (2) firing of action potentials (APs), using a simulation model from hippocampal CA1 pyramidal neurons based on diclofenac's effects on potassium currents. In the NSC-34 cells, diclofenac exerted an inhibitory effect on delayed-rectifier K⁺ current (I(KDR)) with an IC₅₀ value of 73 μM. Diclofenac not merely inhibited the I(KDR) amplitude in response to membrane depolarization, but also accelerated the process of current inactivation. The inhibition by diclofenac of IK(DR) was not reversed by subsequent application of either naloxone. Importantly, diclofenac (300 μM) increased the amplitude of M-type K⁺ current (I)(KM)), while flupirtine (10 μM) or meclofenamic acid (10 μM) enhanced it effectively. Consistently, diclofenac (100 μM) increased the amplitude of I(KM) and diminished the I(KDR) amplitude, with a shortening of inactivation time constant in DRG neurons. Furthermore, by using the simulation modeling, we demonstrated the potential electrophysiological mechanisms underlying changes in AP firing caused by diclofenac. During the exposure to diclofenac, the actions on both I(KM) and I(KDR) could be potential mechanism through which it influences the excitability of fast-spiking neurons. Caution needs to be made in attributing the effects of diclofenac primarily to those produced by the activation of I(KM).
Collapse
Affiliation(s)
- C W Huang
- Department of Neurology, National Cheng Kung University Hospital, School of Medicine, National Cheng Kung University, Tainan City, Taiwan
| | | | | | | | | |
Collapse
|
42
|
Abstract
In humans KCNQ2/3 heteromeric channels form an M-current that acts as a brake on neuronal excitability, with mutations causing a form of epilepsy. The M-current has been shown to be a key regulator of neuronal plasticity underlying associative memory and ethanol response in mammals. Previous work has shown that many of the molecules and plasticity mechanisms underlying changes in alcohol behaviour and addiction are shared with those of memory. We show that the single KCNQ channel in Drosophila (dKCNQ) when mutated show decrements in associative short- and long-term memory, with KCNQ function in the mushroom body α/βneurons being required for short-term memory. Ethanol disrupts memory in wildtype flies, but not in a KCNQ null mutant background suggesting KCNQ maybe a direct target of ethanol, the blockade of which interferes with the plasticity machinery required for memory formation. We show that as in humans, Drosophila display age-related memory impairment with the KCNQ mutant memory defect mimicking the effect of age on memory. Expression of KCNQ normally decreases in aging brains and KCNQ overexpression in the mushroom body neurons of KCNQ mutants restores age-related memory impairment. Therefore KCNQ is a central plasticity molecule that regulates age dependent memory impairment.
Collapse
Affiliation(s)
- Sonia Cavaliere
- School of Physiology and Pharmacology, University of Bristol, Bristol, Avon, United Kingdom
| | - Bilal R. Malik
- School of Physiology and Pharmacology, University of Bristol, Bristol, Avon, United Kingdom
| | - James J. L. Hodge
- School of Physiology and Pharmacology, University of Bristol, Bristol, Avon, United Kingdom
| |
Collapse
|
43
|
Martelli A, Testai L, Breschi MC, Lawson K, McKay NG, Miceli F, Taglialatela M, Calderone V. Vasorelaxation by hydrogen sulphide involves activation of Kv7 potassium channels. Pharmacol Res 2013; 70:27-34. [PMID: 23287425 DOI: 10.1016/j.phrs.2012.12.005] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 02/07/2023]
Abstract
Hydrogen sulphide (H2S) has been recently hypothesized to be an endogenous adipocyte-derived relaxing factor, evoking vasorelaxation of conductance and resistance vessels. Although the activation of ATP-sensitive potassium channels is known to play a central role in H2S-induced vasorelaxation, activation of vascular Kv7 voltage-gated potassium channels has also been suggested. To investigate this possibility, the ability of selective activators and blockers of distinct classes of potassium channels to affect vasodilation induced by the H2S-donor NaHS, as well as NaHS-induced Rb(+) efflux in endothelium-denuded rat aortic rings, was investigated. NaHS-induced changes of membrane potential were fluorimetrically assessed on human vascular smooth muscle (VSM) cells. Modulation of Kv7.4 channels by NaHS was assessed by electrophysiological studies, upon their heterologous expression in CHO cells. In isolated aortic rings, NaHS evoked vasorelaxing responses associated with an increase of Rb(+)-efflux. NaHS promoted membrane hyperpolarization of human VSM cells. These effects were antagonized by selective blockers of Kv7 channels. The H2S-donor caused a left-shift of current activation threshold of Kv7.4 channels expressed in CHO cells. Altogether, these results suggest that the activation of Kv7.4 channels is a key mechanism in the vascular effects of H2S. Given the relevant roles played by Kv7.4 channels in VSM contractility and by H2S in circulatory homeostasis regulation, these findings provide interesting insights to improve our understanding of H2S pathophysiology and to focus on Kv7.4 channels as novel targets for therapeutic approaches via the "H2S-system".
Collapse
MESH Headings
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Cell Line
- Data Interpretation, Statistical
- Dose-Response Relationship, Drug
- Endothelium, Vascular/physiology
- Humans
- Hydrogen Sulfide/pharmacology
- In Vitro Techniques
- KCNQ Potassium Channels/biosynthesis
- KCNQ Potassium Channels/metabolism
- Male
- Membrane Potentials/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Rats
- Rats, Wistar
- Sulfides/pharmacology
- Vasoconstrictor Agents/pharmacology
- Vasodilation/drug effects
Collapse
Affiliation(s)
- A Martelli
- Department of Pharmacy, University of Pisa, via Bonanno, 6, I-56126 Pisa, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
44
|
Abstract
In humans, KCNQ2/3 channels form an M-current that regulates neuronal excitability, with mutations in these channels causing benign neonatal familial convulsions. The M-current is important in mechanisms of neural plasticity underlying associative memory and in the response to ethanol, with KCNQ controlling the release of dopamine after ethanol exposure. We show that dKCNQ is broadly expressed in the nervous system, with targeted reduction in neuronal KCNQ increasing neural excitability and KCNQ overexpression decreasing excitability and calcium signalling, consistent with KCNQ regulating the resting membrane potential and neural release as in mammalian neurons. We show that the single KCNQ channel in Drosophila (dKCNQ) has similar electrophysiological properties to neuronal KCNQ2/3, including conserved acute sensitivity to ethanol block, with the fly channel (IC(50) = 19.8 mM) being more sensitive than its mammalian ortholog (IC(50) = 42.1 mM). This suggests that the role of KCNQ in alcohol behaviour can be determined for the first time by using Drosophila. We present evidence that loss of KCNQ function in Drosophila increased sensitivity and tolerance to the sedative effects of ethanol. Acute activation of dopaminergic neurons by heat-activated TRP channel or KCNQ-RNAi expression produced ethanol hypersensitivity, suggesting that both act via a common mechanism involving membrane depolarisation and increased dopamine signalling leading to ethanol sedation.
Collapse
Affiliation(s)
- Sonia Cavaliere
- School of Physiology and Pharmacology, University of Bristol, Bristol, Avon, United Kingdom
| | | | | |
Collapse
|
45
|
Köhn C, Schleifenbaum J, Szijártó IA, Markó L, Dubrovska G, Huang Y, Gollasch M. Differential effects of cystathionine-γ-lyase-dependent vasodilatory H2S in periadventitial vasoregulation of rat and mouse aortas. PLoS One 2012; 7:e41951. [PMID: 22870268 PMCID: PMC3411702 DOI: 10.1371/journal.pone.0041951] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 06/28/2012] [Indexed: 12/22/2022] Open
Abstract
Background Hydrogen sulfide (H2S) is a potent vasodilator. However, the complex mechanisms of vasoregulation by H2S are not fully understood. We tested the hypotheses that (1) H2S exerts vasodilatory effects by opening KCNQ-type voltage-dependent (Kv) K+ channels and (2) that H2S-producing cystathionine-γ-lyase (CSE) in perivascular adipose tissue plays a major role in this pathway. Methodology/Principal Findings Wire myography of rat and mouse aortas was used. NaHS and 5-(4-hydroxyphenyl)-3H-1,2-dithiole-3-thione (ADTOH) were used as H2S donors. KCNQ-type Kv channels were blocked by XE991. 4-Propargylglycine (PPG) and ß-cyano-l-alanine (BCA), or 2-(aminooxy)-acetic acid (AOAA) were used as inhibitors of CSE or cystathionine-ß-synthase (CBS), respectively. NaHS and ADTOH produced strong vasorelaxation in rat and mouse aortas, which were abolished by KCNQ channel inhibition with XE991. Perivascular adipose tissue (PVAT) exerted an anticontractile effect in these arteries. CSE inhibition by PPG and BCA reduced this effect in aortas from rats but not from mice. CBS inhibition with AOAA did not inhibit the anticontractile effects of PVAT. XE991, however, almost completely suppressed the anticontractile effects of PVAT in both species. Exogenous l-cysteine, substrate for the endogenous production of H2S, induced vasorelaxation only at concentrations >5 mmol/l, an effect unchanged by CSE inhibition. Conclusions/Signficance Our results demonstrate potent vasorelaxant effects of H2S donors in large arteries of both rats and mice, in which XE991-sensitive KCNQ-type channel opening play a pivotal role. CSE-H2S seems to modulate the effect of adipocyte-derived relaxing factor in rat but not in mouse aorta. The present study provides novel insight into the interaction of CSE-H2S and perivascular adipose tissue. Furthermore, with additional technical advances, a future clinical approach targeting vascular H2S/KCNQ pathways to influence states of vascular dysfunction may be possible.
Collapse
Affiliation(s)
- Carolin Köhn
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum and Experimental and Clinical Research Center (ECRC), Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Johanna Schleifenbaum
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum and Experimental and Clinical Research Center (ECRC), Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - István András Szijártó
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum and Experimental and Clinical Research Center (ECRC), Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Lajos Markó
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum and Experimental and Clinical Research Center (ECRC), Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Galyna Dubrovska
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum and Experimental and Clinical Research Center (ECRC), Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Yu Huang
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Maik Gollasch
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum and Experimental and Clinical Research Center (ECRC), Max Delbrück Center for Molecular Medicine, Berlin, Germany
- * E-mail:
| |
Collapse
|
46
|
Ren L, Wang Y, Shi M, Wang X, Yang Z, Zhao Z. CTCF mediates the cell-type specific spatial organization of the Kcnq5 locus and the local gene regulation. PLoS One 2012; 7:e31416. [PMID: 22347474 PMCID: PMC3275579 DOI: 10.1371/journal.pone.0031416] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 01/07/2012] [Indexed: 11/30/2022] Open
Abstract
Chromatin loops play important roles in the dynamic spatial organization of genes in the nucleus. Growing evidence has revealed that the multivalent functional zinc finger protein CCCTC-binding factor (CTCF) is a master regulator of genome spatial organization, and mediates the ubiquitous chromatin loops within the genome. Using circular chromosome conformation capture (4C) methodology, we discovered that CTCF may be a master organizer in mediating the spatial organization of the kcnq5 gene locus. We characterized the cell-type specific spatial organization of the kcnq5 gene locus mediated by CTCF in detail using chromosome conformation capture (3C) and 3C-derived techniques. Cohesion also participated in mediating the organization of this locus. RNAi-mediated knockdown of CTCF sharply diminished the interaction frequencies between the chromatin loops of the kcnq5 gene locus and down-regulated local gene expression. Functional analysis showed that the interacting chromatin loops of the kcnq5 gene locus can repress the gene expression in a luciferase reporter assay. These interacting chromatin fragments were a series of repressing elements whose contacts were mediated by CTCF. Therefore, these findings suggested that the dynamical spatial organization of the kcnq5 locus regulates local gene expression.
Collapse
Affiliation(s)
- Licheng Ren
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yang Wang
- Beijing Institute of Biotechnology, Fengtai District, Beijing, China
| | - Minglei Shi
- Beijing Institute of Biotechnology, Fengtai District, Beijing, China
| | - Xiaoning Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- State Key Laboratory of Genetic Engineering and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, China
- * E-mail: (ZZ); (ZY); (XW)
| | - Zhong Yang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- State Key Laboratory of Genetic Engineering and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, China
- * E-mail: (ZZ); (ZY); (XW)
| | - Zhihu Zhao
- Beijing Institute of Biotechnology, Fengtai District, Beijing, China
- * E-mail: (ZZ); (ZY); (XW)
| |
Collapse
|
47
|
Abstract
Phosphoinositides, especially phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] are required for the activity of many different ion channels. This chapter will highlight various aspects of this paradigm, by discussing current knowledge on four different ion channel families: inwardly rectifying K(+) (Kir) channels, KCNQ voltage gated K(+) channels, voltage gated Ca(2+) (VGCC) channels and Transient Receptor Potential (TRP) channels. Our main focus is to discuss functional aspects of this regulation, i.e. how changes in the concentration of PtdIns(4,5)P(2) in the plasma membrane upon phospholipase C activation may modulate the activity of ion channels, and what are the major determinants of this regulation. We also discuss how channels act as coincidence detectors sensing phosphoinositide levels and other signalling molecules. We also briefly discuss the available methods to study phosphoinositide regulation of ion channels, and structural aspects of interaction of ion channel proteins with these phospholipids. Finally, in several cases the effect of PtdIns(4,5)P(2) is more complex than a simple dependence of ion channel activity on the lipid, and we will discuss some these complexities.
Collapse
Affiliation(s)
- Nikita Gamper
- Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT, Leeds, UK,
| | | |
Collapse
|
48
|
Cavaliere S, Hodge JJL. Drosophila KCNQ channel displays evolutionarily conserved electrophysiology and pharmacology with mammalian KCNQ channels. PLoS One 2011; 6:e23898. [PMID: 21915266 PMCID: PMC3168433 DOI: 10.1371/journal.pone.0023898] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 07/26/2011] [Indexed: 11/19/2022] Open
Abstract
Of the five human KCNQ (Kv7) channels, KCNQ1 with auxiliary subunit KCNE1 mediates the native cardiac I(Ks) current with mutations causing short and long QT cardiac arrhythmias. KCNQ4 mutations cause deafness. KCNQ2/3 channels form the native M-current controlling excitability of most neurons, with mutations causing benign neonatal febrile convulsions. Drosophila contains a single KCNQ (dKCNQ) that appears to serve alone the functions of all the duplicated mammalian neuronal and cardiac KCNQ channels sharing roughly 50-60% amino acid identity therefore offering a route to investigate these channels. Current information about the functional properties of dKCNQ is lacking therefore we have investigated these properties here. Using whole cell patch clamp electrophysiology we compare the biophysical and pharmacological properties of dKCNQ with the mammalian neuronal and cardiac KCNQ channels expressed in HEK cells. We show that Drosophila KCNQ (dKCNQ) is a slowly activating and slowly-deactivating K(+) current open at sub-threshold potentials that has similar properties to neuronal KCNQ2/3 with some features of the cardiac KCNQ1/KCNE1 accompanied by conserved sensitivity to a number of clinically relevant KCNQ blockers (chromanol 293B, XE991, linopirdine) and opener (zinc pyrithione). We also investigate the molecular basis of the differential selectivity of KCNQ channels to the opener retigabine and show a single amino acid substitution (M217W) can confer sensitivity to dKCNQ. We show dKCNQ has similar electrophysiological and pharmacological properties as the mammalian KCNQ channels, allowing future study of physiological and pathological roles of KCNQ in Drosophila and whole organism screening for new modulators of KCNQ channelopathies.
Collapse
Affiliation(s)
- Sonia Cavaliere
- University of Bristol, School of Physiology and Pharmacology, Medical Sciences Building, Bristol, United Kingdom
| | - James J. L. Hodge
- University of Bristol, School of Physiology and Pharmacology, Medical Sciences Building, Bristol, United Kingdom
| |
Collapse
|
49
|
Qi J, Zhang F, Mi Y, Fu Y, Xu W, Zhang D, Wu Y, Du X, Jia Q, Wang K, Zhang H. Design, synthesis and biological activity of pyrazolo[1,5-a]pyrimidin-7(4H)-ones as novel Kv7/KCNQ potassium channel activators. Eur J Med Chem 2011; 46:934-43. [PMID: 21296466 DOI: 10.1016/j.ejmech.2011.01.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Revised: 12/20/2010] [Accepted: 01/10/2011] [Indexed: 11/17/2022]
Abstract
Voltage-gated Kv7/KCNQ/M-potassium channels play a pivotal role in controlling neuronal excitability. Genetic reduction of KCNQ channel activity as a result of mutations causes various human diseases such as epilepsy and arrhythmia. Therefore, discovery of small molecules that activate KCNQ channels is an important strategy for clinical intervention of membrane excitability related disorders. In this study, a series of pyrazolo[1,5-a]pyrimidin-7(4H)-ones (PPOs) have been found to be novel activators (openers) of KCNQ2/3 potassium channels through high-throughput screening by using atomic absorption rubidium efflux assay. Based on structure-activity relationship (SAR), the substituted PPOs have been optimized. The 5-(2,6-dichloro-5-fluoropyridin-3-yl)-3-phenyl-2-(trifluoromethyl) pyrazolo[1,5-a]pyrimidin-7(4H)-one (17) was identified as a novel, potent, and selective KCNQ2/3 potassium channel opener by patch-clamp recording assay.
Collapse
Affiliation(s)
- Jinlong Qi
- Department of Development for New Drugs, School of Pharmacy, Hebei Medical University, Shijiazhuang 050017, China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Blom SM, Schmitt N, Jensen HS. The acrylamide (S)-2 as a positive and negative modulator of Kv7 channels expressed in Xenopus laevis oocytes. PLoS One 2009; 4:e8251. [PMID: 20011514 PMCID: PMC2788219 DOI: 10.1371/journal.pone.0008251] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 11/17/2009] [Indexed: 01/18/2023] Open
Abstract
Background Activation of voltage-gated potassium channels of the Kv7 (KCNQ) family reduces cellular excitability. These channels are therefore attractive targets for treatment of diseases characterized by hyperexcitability, such as epilepsy, migraine and neuropathic pain. Retigabine, which opens Kv7.2-5, is now in clinical trial phase III for the treatment of partial onset seizures. One of the main obstacles in developing Kv7 channel active drugs has been to identify compounds that can discriminate between the neuronal subtypes, a feature that could help diminish side effects and increase the potential of drugs for particular indications. Methodology/Principal Findings In the present study we have made a thorough investigation of the Bristol-Myers Squibb compound (S)-N-[1-(4-Cyclopropylmethyl-3,4-dihydro-2H-benzo[1], [4]oxazin-6-yl)-ethyl]-3-(2-fluoro-phenyl)-acrylamide [(S)-2] on human Kv7.1-5 channels expressed in Xenopus laevis oocytes. We found that the compound was a weak inhibitor of Kv7.1. In contrast, (S)-2 efficiently opened Kv7.2-5 by producing hyperpolarizing shifts in the voltage-dependence of activation and enhancing the maximal current amplitude. Further, it reduced inactivation, accelerated activation kinetics and slowed deactivation kinetics. The mechanisms of action varied between the subtypes. The enhancing effects of (S)-2 were critically dependent on a tryptophan residue in S5 also known to be crucial for the effects of retigabine, (S)-1 and BMS-204352. However, while (S)-2 did not at all affect a mutant Kv7.4 with a leucine in this position (Kv7.4-W242L), a Kv7.2 with the same mutation (Kv7.2-W236L) was inhibited by the compound, showing that (S)-2 displays a subtype-selective interaction with in the Kv7 family. Conclusions/Significance These results offer further insight into pharmacological activation of Kv7 channels, add to the understanding of small molecule interactions with the channels and may contribute to the design of subtype selective modulators.
Collapse
Affiliation(s)
- Sigrid Marie Blom
- Section of Early Target Pharmacology and Physiology, H. Lundbeck A/S, Copenhagen, Denmark
- Department of Biomedical Sciences and Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Nicole Schmitt
- Department of Biomedical Sciences and Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Sindal Jensen
- Section of Early Target Pharmacology and Physiology, H. Lundbeck A/S, Copenhagen, Denmark
- * E-mail:
| |
Collapse
|