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Stagno C, Mancuso F, Ciaglia T, Ostacolo C, Piperno A, Iraci N, Micale N. In Silico Methods for the Discovery of Kv7.2/7.3 Channels Modulators: A Comprehensive Review. Molecules 2024; 29:3234. [PMID: 38999185 PMCID: PMC11243076 DOI: 10.3390/molecules29133234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2024] [Revised: 07/03/2024] [Accepted: 07/05/2024] [Indexed: 07/14/2024] Open
Abstract
The growing interest in Kv7.2/7.3 agonists originates from the involvement of these channels in several brain hyperexcitability disorders. In particular, Kv7.2/7.3 mutants have been clearly associated with epileptic encephalopathies (DEEs) as well as with a spectrum of focal epilepsy disorders, often associated with developmental plateauing or regression. Nevertheless, there is a lack of available therapeutic options, considering that retigabine, the only molecule used in clinic as a broad-spectrum Kv7 agonist, has been withdrawn from the market in late 2016. This is why several efforts have been made both by both academia and industry in the search for suitable chemotypes acting as Kv7.2/7.3 agonists. In this context, in silico methods have played a major role, since the precise structures of different Kv7 homotetramers have been only recently disclosed. In the present review, the computational methods used for the design of Kv.7.2/7.3 small molecule agonists and the underlying medicinal chemistry are discussed in the context of their biological and structure-function properties.
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Affiliation(s)
- Claudio Stagno
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Francesca Mancuso
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Tania Ciaglia
- Department of Pharmacy, University of Salerno, Via G. Paolo II, 84084 Fisciano, Italy
| | - Carmine Ostacolo
- Department of Pharmacy, University of Salerno, Via G. Paolo II, 84084 Fisciano, Italy
| | - Anna Piperno
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Nunzio Iraci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Nicola Micale
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
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2
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Li Y, Wu Z, Zhao Y, Shi L. Anti-seizure medications-associated bladder and urethral symptoms: a pharmacovigilance analysis based on the FAERS database. Expert Opin Drug Saf 2024:1-10. [PMID: 38871672 DOI: 10.1080/14740338.2024.2368820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 04/16/2024] [Indexed: 06/15/2024]
Abstract
BACKGROUND In clinical practice, observations have been made regarding bladder and urethral symptoms (BUS), notably urinary frequency and urgency, among patients prescribed the anti-seizure medication (ASM) lacosamide. However, the precise association between ASMs and BUS events in real-world settings remains elusive. RESEARCH DESIGN AND METHODS Data from the FDA Adverse Event Reporting System (FAERS) database were employed and the analysis focused on ASMs-associated BUS events utilizing disproportionality analysis methods, including the reporting odds ratio (ROR) and the proportional reporting ratio (PRR). Furthermore, co-administration, time to onset of ASMs-associated BUS events, and severity assessments were conducted. RESULTS Several ASMs demonstrated statistically meaningful associations with BUS signals, notably ezogabine, valproic acid/valproate sodium, and clorazepate (p < 0.05). And ASMs-associated BUS events predominantly occurred within the first week and persisted for more than 180 days afterward. Diazepam, gabapentin, and brivaracetam exhibited distinct risk profiles for severe BUS events compared to valproic acid/sodium valproate (p < 0.05). And the nomogram constructed in this study exhibited robust predictive performance. CONCLUSION This study yields valuable insights into the association between ASMs and BUS events, but several limitations warrant consideration. Nonetheless, these findings emphasize the significance of vigilance and proactive management of ASMs-associated BUS events.
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Affiliation(s)
- Yanyan Li
- Department of Pharmacy, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhanshen Wu
- Department of Pharmacy, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yang Zhao
- Department of Pharmacy, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Lei Shi
- Department of Pharmacy, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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3
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Stott JB, Greenwood IA. G protein βγ regulation of KCNQ-encoded voltage-dependent K channels. Front Physiol 2024; 15:1382904. [PMID: 38655029 PMCID: PMC11035767 DOI: 10.3389/fphys.2024.1382904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The KCNQ family is comprised of five genes and the expression products form voltage-gated potassium channels (Kv7.1-7.5) that have a major impact upon cellular physiology in many cell types. Each functional Kv7 channel forms as a tetramer that often associates with proteins encoded by the KCNE gene family (KCNE1-5) and is critically reliant upon binding of phosphatidylinositol bisphosphate (PIP2) and calmodulin. Other modulators like A-kinase anchoring proteins, ubiquitin ligases and Ca-calmodulin kinase II alter Kv7 channel function and trafficking in an isoform specific manner. It has now been identified that for Kv7.4, G protein βγ subunits (Gβγ) can be added to the list of key regulators and is paramount for channel activity. This article provides an overview of this nascent field of research, highlighting themes and directions for future study.
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Affiliation(s)
| | - Iain A. Greenwood
- Vascular Biology Research Group, Institute of Molecular and Clinical Sciences, St George’s University of London, London, United Kingdom
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4
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Gao J, Yin H, Dong Y, Wang X, Liu Y, Wang K. A Novel Role of Uricosuric Agent Benzbromarone in BK Channel Activation and Reduction of Airway Smooth Muscle Contraction. Mol Pharmacol 2023; 103:241-254. [PMID: 36669879 DOI: 10.1124/molpharm.122.000638] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/28/2022] [Accepted: 12/19/2022] [Indexed: 01/21/2023] Open
Abstract
The uricosuric drug benzbromarone, widely used for treatment of gout, hyperpolarizes the membrane potential of airway smooth muscle cells, but how it works remains unknown. Here we show a novel role of benzbromarone in activation of large conductance calcium-activated K+ channels. Benzbromarone results in dose-dependent activation of macroscopic big potassium (BK) currents about 1.7- to 14.5-fold with an EC50 of 111 μM and shifts the voltage-dependent channel activation to a more hyperpolarizing direction about 10 to 54 mV in whole-cell patch clamp recordings. In single-channel recordings, benzbromarone decreases single BKα channel closed dwell time and increases the channel open probability. Coexpressing β1 subunit also enhances BK activation by benzbromarone with an EC50 of 67 μM and a leftward shift of conductance-voltage (G-V) curve about 44 to 138 mV. Site-directed mutagenesis reveals that a motif of three amino acids 329RKK331 in the cytoplasmic linker between S6 and C-terminal regulator of potassium conductance (RCK) gating ring mediates the pharmacological activation of BK channels by benzbromarone. Further ex vivo assay shows that benzbromarone causes reduction of tracheal strip contraction. Taken together, our findings demonstrate that uricosuric benzbromarone activates BK channels through molecular mechanism of action involving the channel RKK motif of S6-RCK linker. Pharmacological activation of BK channel by benzbromarone causes reduction of tracheal strip contraction, holding a repurposing potential for asthma and pulmonary arterial hypertension or BK channelopathies. SIGNIFICANCE STATEMENT: We describe a novel role of uricosuric agent benzbromarone in big potassium (BK) channel activation and relaxation of airway smooth muscle contraction. In this study, we find that benzbromarone is an activator of the large-conductance Ca2+- and voltage-activated K+ channel (BK channel), which serves numerous cellular functions, including control of smooth muscle contraction. Pharmacological activation of BK channel by the FDA-approved drug benzbromarone may hold repurposing potential for treatment of asthma and pulmonary arterial hypertension or BK channelopathies.
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Affiliation(s)
- Jian Gao
- Department of Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China (J.G., X.W.); Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China (H.Y., Y.D., Y.L., K.W.); and Institute of Innovative Drugs, Qingdao University, Qingdao, China (Y.L., K.W.)
| | - Hao Yin
- Department of Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China (J.G., X.W.); Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China (H.Y., Y.D., Y.L., K.W.); and Institute of Innovative Drugs, Qingdao University, Qingdao, China (Y.L., K.W.)
| | - Yanqun Dong
- Department of Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China (J.G., X.W.); Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China (H.Y., Y.D., Y.L., K.W.); and Institute of Innovative Drugs, Qingdao University, Qingdao, China (Y.L., K.W.)
| | - Xintong Wang
- Department of Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China (J.G., X.W.); Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China (H.Y., Y.D., Y.L., K.W.); and Institute of Innovative Drugs, Qingdao University, Qingdao, China (Y.L., K.W.)
| | - Yani Liu
- Department of Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China (J.G., X.W.); Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China (H.Y., Y.D., Y.L., K.W.); and Institute of Innovative Drugs, Qingdao University, Qingdao, China (Y.L., K.W.)
| | - KeWei Wang
- Department of Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China (J.G., X.W.); Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China (H.Y., Y.D., Y.L., K.W.); and Institute of Innovative Drugs, Qingdao University, Qingdao, China (Y.L., K.W.)
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5
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Emerging mechanisms involving brain Kv7 channel in the pathogenesis of hypertension. Biochem Pharmacol 2022; 206:115318. [PMID: 36283445 DOI: 10.1016/j.bcp.2022.115318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022]
Abstract
Hypertension is a prevalent health problem inducing many organ damages. The pathogenesis of hypertension involves a complex integration of different organ systems including the brain. The elevated sympathetic nerve activity is closely related to the etiology of hypertension. Ion channels are critical regulators of neuronal excitability. Several mechanisms have been proposed to contribute to hypothalamic-driven elevated sympathetic activity, including altered ion channel function. Recent findings indicate one of the voltage-gated potassium channels, Kv7 channels (M channels), plays a vital role in regulating cardiovascular-related neurons activity, and the expression of Kv7 channels is downregulated in hypertension. This review highlights recent findings that the Kv7 channels in the brain, blood vessels, and kidneys are emerging targets involved in the pathogenesis of hypertension, suggesting new therapeutic targets for treating drug-resistant, neurogenic hypertension.
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6
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Wei AD, Wakenight P, Zwingman TA, Bard AM, Sahai N, Willemsen MH, Schelhaas HJ, Stegmann APA, Verhoeven JS, de Man SA, Wessels MW, Kleefstra T, Shinde DN, Helbig KL, Basinger A, Wagner VF, Rodriguez-Buritica D, Bryant E, Millichap JJ, Millen KJ, Dobyns WB, Ramirez JM, Kalume FK. Human KCNQ5 de novo mutations underlie epilepsy and intellectual disability. J Neurophysiol 2022; 128:40-61. [PMID: 35583973 PMCID: PMC9236882 DOI: 10.1152/jn.00509.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
We identified six novel de novo human KCNQ5 variants in children with motor/language delay, intellectual disability (ID), and/or epilepsy by whole exome sequencing. These variants, comprising two nonsense and four missense alterations, were functionally characterized by electrophysiology in HEK293/CHO cells, together with four previously reported KCNQ5 missense variants (Lehman A, Thouta S, Mancini GM, Naidu S, van Slegtenhorst M, McWalter K, Person R, Mwenifumbo J, Salvarinova R; CAUSES Study; EPGEN Study; Guella I, McKenzie MB, Datta A, Connolly MB, Kalkhoran SM, Poburko D, Friedman JM, Farrer MJ, Demos M, Desai S, Claydon T. Am J Hum Genet 101: 65-74, 2017). Surprisingly, all eight missense variants resulted in gain of function (GOF) due to hyperpolarized voltage dependence of activation or slowed deactivation kinetics, whereas the two nonsense variants were confirmed to be loss of function (LOF). One severe GOF allele (P369T) was tested and found to extend a dominant GOF effect to heteromeric KCNQ5/3 channels. Clinical presentations were associated with altered KCNQ5 channel gating: milder presentations with LOF or smaller GOF shifts in voltage dependence [change in voltage at half-maximal conduction (ΔV50) = ∼-15 mV] and severe presentations with larger GOF shifts in voltage dependence (ΔV50 = ∼-30 mV). To examine LOF pathogenicity, two Kcnq5 LOF mouse lines were created with CRISPR/Cas9. Both lines exhibited handling- and thermal-induced seizures and abnormal cortical EEGs consistent with epileptiform activity. Our study thus provides evidence for in vivo KCNQ5 LOF pathogenicity and strengthens the contribution of both LOF and GOF mutations to global pediatric neurological impairment, including ID/epilepsy.NEW & NOTEWORTHY Six novel de novo human KCNQ5 variants were identified from children with neurodevelopmental delay, intellectual disability, and/or epilepsy. Expression of these variants along with four previously reported KCNQ5 variants from a similar cohort revealed GOF potassium channels, negatively shifted in V50 of activation and/or delayed deactivation kinetics. GOF is extended to KCNQ5/3 heteromeric channels, making these the predominant channels affected in heterozygous de novo patients. Kcnq5 LOF mice exhibited seizures, consistent with in vivo pathogenicity.
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Affiliation(s)
- Aguan D Wei
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Paul Wakenight
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Theresa A Zwingman
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Angela M Bard
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Nikhil Sahai
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Marjolein H Willemsen
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Helenius J Schelhaas
- Department of Neurology, Academic Centre for Epileptology Kempenhaeghe, Heeze, The Netherlands
| | - Alexander P A Stegmann
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Judith S Verhoeven
- Department of Neurology, Academic Centre for Epileptology Kempenhaeghe, Heeze, The Netherlands
| | - Stella A de Man
- Department of Pediatrics, Amphia Hospital, Breda, The Netherlands.,Department of Human Genetics, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Marja W Wessels
- Department of Human Genetics, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Tjitske Kleefstra
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Katherine L Helbig
- Ambry Genetics, Aliso Viejo, California.,Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Alice Basinger
- Medical Genetics, Cook Children's Hospital, Fort Worth, Texas
| | - Victoria F Wagner
- Department of Pediatrics, University of Texas Health Science Center, Houston, Texas
| | | | - Emily Bryant
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - John J Millichap
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Epilepsy Center, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Kathleen J Millen
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington.,Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington
| | - William B Dobyns
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington.,Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington.,Department of Neurology, University of Washington School of Medicine, Seattle, Washington
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington.,Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington
| | - Franck K Kalume
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington.,Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington
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7
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Peixoto-Neves D, Kanthakumar P, Afolabi JM, Soni H, Buddington RK, Adebiyi A. K V7.1 channel blockade inhibits neonatal renal autoregulation triggered by a step decrease in arterial pressure. Am J Physiol Renal Physiol 2022; 322:F197-F207. [PMID: 35001664 PMCID: PMC8816635 DOI: 10.1152/ajprenal.00568.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
KV7 channels, the voltage-gated K+ channels encoded by KCNQ genes, mediate heterogeneous vascular responses in rodents. Postnatal changes in the functional expression of KV7 channels have been reported in rodent saphenous arteries, but their physiological function in the neonatal renal vascular bed is unclear. Here, we report that, unlike adult pigs, only KCNQ1 (KV7.1) out of the five members of KCNQ genes was detected in neonatal pig renal microvessels. KCNQ1 is present in fetal pig kidneys as early as day 50 of gestation, and the level of expression remains the same up to postnatal day 21. Activation of renal vascular smooth muscle cell (SMC) KV7.1 stimulated whole cell currents, inhibited by HMR1556 (HMR), a selective KV7.1 blocker. HMR did not change the steady-state diameter of isolated renal microvessels. Similarly, intrarenal artery infusion of HMR did not alter mean arterial pressure, renal blood flow, and renal vascular resistance in the pigs. An ∼20 mmHg reduction in mean arterial pressure evoked effective autoregulation of renal blood flow, which HMR inhibited. We conclude that 1) the expression of KCNQ isoforms in porcine renal microvessels is dependent on kidney maturation, 2) KV7.1 is functionally expressed in neonatal pig renal vascular SMCs, 3) a decrease in arterial pressure up to 20 mmHg induces renal autoregulation in neonatal pigs, and 4) SMC KV7.1 does not control basal renal vascular tone but contributes to neonatal renal autoregulation triggered by a step decrease in arterial pressure.NEW & NOTEWORTHY KV7.1 is present in fetal pig kidneys as early as day 50 of gestation, and the level of expression remains the same up to postnatal day 21. KV7.1 is functionally expressed in neonatal pig renal vascular smooth muscle cells (SMCs). A decrease in arterial pressure up to 20 mmHg induces renal autoregulation in neonatal pigs. Although SMC KV7.1 does not control basal renal vascular resistance, its inhibition blunts neonatal renal autoregulation engendered by a step decrease in arterial pressure.
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Affiliation(s)
- Dieniffer Peixoto-Neves
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Jeremiah M. Afolabi
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Hitesh Soni
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Adebowale Adebiyi
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
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8
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Jackson WF. Calcium-Dependent Ion Channels and the Regulation of Arteriolar Myogenic Tone. Front Physiol 2021; 12:770450. [PMID: 34819877 PMCID: PMC8607693 DOI: 10.3389/fphys.2021.770450] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/11/2021] [Indexed: 11/25/2022] Open
Abstract
Arterioles in the peripheral microcirculation regulate blood flow to and within tissues and organs, control capillary blood pressure and microvascular fluid exchange, govern peripheral vascular resistance, and contribute to the regulation of blood pressure. These important microvessels display pressure-dependent myogenic tone, the steady state level of contractile activity of vascular smooth muscle cells (VSMCs) that sets resting arteriolar internal diameter such that arterioles can both dilate and constrict to meet the blood flow and pressure needs of the tissues and organs that they perfuse. This perspective will focus on the Ca2+-dependent ion channels in the plasma and endoplasmic reticulum membranes of arteriolar VSMCs and endothelial cells (ECs) that regulate arteriolar tone. In VSMCs, Ca2+-dependent negative feedback regulation of myogenic tone is mediated by Ca2+-activated K+ (BKCa) channels and also Ca2+-dependent inactivation of voltage-gated Ca2+ channels (VGCC). Transient receptor potential subfamily M, member 4 channels (TRPM4); Ca2+-activated Cl− channels (CaCCs; TMEM16A/ANO1), Ca2+-dependent inhibition of voltage-gated K+ (KV) and ATP-sensitive K+ (KATP) channels; and Ca2+-induced-Ca2+ release through inositol 1,4,5-trisphosphate receptors (IP3Rs) participate in Ca2+-dependent positive-feedback regulation of myogenic tone. Calcium release from VSMC ryanodine receptors (RyRs) provide negative-feedback through Ca2+-spark-mediated control of BKCa channel activity, or positive-feedback regulation in cooperation with IP3Rs or CaCCs. In some arterioles, VSMC RyRs are silent. In ECs, transient receptor potential vanilloid subfamily, member 4 (TRPV4) channels produce Ca2+ sparklets that activate IP3Rs and intermediate and small conductance Ca2+ activated K+ (IKCa and sKCa) channels causing membrane hyperpolarization that is conducted to overlying VSMCs producing endothelium-dependent hyperpolarization and vasodilation. Endothelial IP3Rs produce Ca2+ pulsars, Ca2+ wavelets, Ca2+ waves and increased global Ca2+ levels activating EC sKCa and IKCa channels and causing Ca2+-dependent production of endothelial vasodilator autacoids such as NO, prostaglandin I2 and epoxides of arachidonic acid that mediate negative-feedback regulation of myogenic tone. Thus, Ca2+-dependent ion channels importantly contribute to many aspects of the regulation of myogenic tone in arterioles in the microcirculation.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
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9
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Zhang D, Krause BM, Schmalz HG, Wohlfart P, Yard BA, Schubert R. ET-CORM Mediated Vasorelaxation of Small Mesenteric Arteries: Involvement of Kv7 Potassium Channels. Front Pharmacol 2021; 12:702392. [PMID: 34552483 PMCID: PMC8451721 DOI: 10.3389/fphar.2021.702392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/24/2021] [Indexed: 11/18/2022] Open
Abstract
Although the vasoactive properties of carbon monoxide (CO) have been extensively studied, the mechanism by which CO mediates vasodilation is not completely understood. Through-out published studies on CO mediated vasodilation there is inconsistency on the type of K+-channels that are activated by CO releasing molecules (CORMs). Since the vasorelaxation properties of enzyme triggered CORMs (ET-CORMs) have not been studied thus far, we first assessed if ET-CORMs can mediate vasodilation of small mesenteric arteries and subsequently addressed the role of soluble guanylate cyclase (sGC) and that of K-channels herein. To this end, 3 different types of ET-CORMs that either contain acetate (rac-1 and rac-4) or pivalate (rac-8) as ester functionality, were tested ex vivo on methoxamine pre-contracted small rat mesenteric arteries in a myograph setting. Pre-contracted mesenteric arteries strongly dilated upon treatment with both types of acetate containing ET-CORMs (rac-1 and rac-4), while treatment with the pivalate containing ET-CORM (rac-8) resulted in no vasodilation. Pre-treatment of mesenteric arteries with the sGC inhibitor ODQ abolished rac-4 mediated vasodilation, similar as for the known sGC activator SNP. Likewise, rac-4 mediated vasodilation did not occur in KCL pretreated mesenteric arteries. Although mesenteric arteries abundantly expressed a variety of K+-channels only Kv7 channels were found to be of functional relevance for rac-4 mediated vasodilation. In conclusion the current results identified Kv7 channels as the main channel by which rac-4 mediates vasodilation. In keeping with the central role of Kv7 in the control of vascular tone and peripheral resistance these promising ex-vivo data warrant further in vivo studies, particularly in models of primary hypertension or cardiac diseases, to assess the potential use of ET-CORMs in these diseases.
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Affiliation(s)
- Danfeng Zhang
- Department of Nephrology, Endocrinology and Rheumatology, Fifth Medical Department of Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.,Department of Nephrology, the Second Hospital of Anhui Medical University, Hefei, China
| | | | | | - Paulus Wohlfart
- Diabetes Research, Sanofi Aventis Deutschland GmbH, Frankfurt, Germany
| | - Benito A Yard
- Department of Nephrology, Endocrinology and Rheumatology, Fifth Medical Department of Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.,European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Frankfurt, Germany
| | - Rudolf Schubert
- European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Frankfurt, Germany.,Physiology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
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10
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Jepps TA. Kv7 channel trafficking by the microtubule network in vascular smooth muscle. Acta Physiol (Oxf) 2021; 232:e13692. [PMID: 34021973 PMCID: PMC8365713 DOI: 10.1111/apha.13692] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 12/17/2022]
Abstract
In arterial smooth muscle cells, changes in availability of integral membrane proteins influence the regulation of blood flow and blood pressure, which is critical for human health. However, the mechanisms that coordinate the trafficking and membrane expression of specific receptors and ion channels in vascular smooth muscle are poorly understood. In the vasculature, very little is known about microtubules, which form a road network upon which proteins can be transported to and from the cell membrane. This review article summarizes the impact of the microtubule network on arterial contractility, highlighting the importance of the network, with an emphasis on our recent findings regarding the trafficking of the voltage‐dependent Kv7 channels.
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Affiliation(s)
- Thomas A Jepps
- Vascular Biology Group Department of Biomedical Sciences University of Copenhagen Blegdamsvej 3 2200 Copenhagen N Denmark
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11
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Naffaa MM, Al-Ewaidat OA. Ligand modulation of KCNQ-encoded (K V7) potassium channels in the heart and nervous system. Eur J Pharmacol 2021; 906:174278. [PMID: 34174270 DOI: 10.1016/j.ejphar.2021.174278] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/06/2021] [Accepted: 06/18/2021] [Indexed: 10/21/2022]
Abstract
KCNQ-encoded (KV7) potassium channels are diversely distributed in the human tissues, associated with many physiological processes and pathophysiological conditions. These channels are increasingly used as drug targets for treating diseases. More selective and potent molecules on various types of the KV7 channels are desirable for appropriate therapies. The recent knowledge of the structure and function of human KCNQ-encoded channels makes it more feasible to achieve these goals. This review discusses the role and mechanism of action of many molecules in modulating the function of the KCNQ-encoded potassium channels in the heart and nervous system. The effects of these compounds on KV7 channels help to understand their involvement in many diseases, and to search for more selective and potent ligands to be used in the treatment of many disorders such as various types of cardiac arrhythmias, epilepsy, and pain.
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Affiliation(s)
- Moawiah M Naffaa
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA; Department of Psychology and Neuroscience, Duke University, Durham, NC 27708, USA.
| | - Ola A Al-Ewaidat
- Faculty of Medicine, The University of Jordan, Amman, 11942, Jordan
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12
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Ma D, Gaynullina D, Schmidt N, Mladenov M, Schubert R. The Functional Availability of Arterial Kv7 Channels Is Suppressed Considerably by Large-Conductance Calcium-Activated Potassium Channels in 2- to 3-Month Old but Not in 10- to 15-Day Old Rats. Front Physiol 2020; 11:597395. [PMID: 33384611 PMCID: PMC7770149 DOI: 10.3389/fphys.2020.597395] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/24/2020] [Indexed: 01/26/2023] Open
Abstract
Background Voltage-gated potassium (Kv) channels, especially Kv7 channels, are major potassium channels identified in vascular smooth muscle cells with a great, albeit differential functional impact in various vessels. Vascular smooth muscle Kv7 channels always coexist with other K channels, in particular with BK channels. BK channels differ in the extent to which they influence vascular contractility. Whether this difference also causes the variability in the functional impact of Kv7 channels is unknown. Therefore, this study addressed the hypothesis that the functional impact of Kv7 channels depends on BK channels. Experimental Approach Experiments were performed on young and adult rat gracilis and saphenous arteries using real-time PCR as well as pressure and wire myography. Key Results Several subfamily members of Kv7 (KCNQ) and BK channels were expressed in saphenous and gracilis arteries: the highest expression was observed for BKα, BKβ1 and KCNQ4. Arterial contractility was assessed with methoxamine-induced contractions and pressure-induced myogenic responses. In vessels of adult rats, inhibition of Kv7 channels or BK channels by XE991 or IBTX, respectively enhanced arterial contractility to a similar degree, whereas activation of Kv7 channels or BK channels by retigabine or NS19504, respectively reduced arterial contractility to a similar degree. Further, IBTX increased both the contractile effect of XE991 and the anticontractile effect of retigabine, whereas NS19504 reduced the effect of retigabine and impaired the effect of XE991. In vessels of young rats, inhibition of Kv7 channels by XE991 enhanced arterial contractility much stronger than inhibition of BK channels by IBTX, whereas activation of Kv7 by retigabine reduced arterial contractility to a greater extent than activation of BK channels by NS19504. Further, IBTX increased the anticontractile effect of retigabine but not the contractile effect of XE991, whereas NS19504 reduced the effect of retigabine and impaired the effect of XE991. Conclusion Kv7 and BK channels are expressed in young and adult rat arteries and function as negative feedback modulators in the regulation of contractility of these arteries. Importantly, BK channels govern the extent of functional impact of Kv7 channels. This effect depends on the relationship between the functional activities of BK and Kv7 channels.
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Affiliation(s)
- Dongyu Ma
- European Center for Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Department of Cardiology, The First Affiliated Hospital of Anhui Medical University, Anhui, China
| | - Dina Gaynullina
- European Center for Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Nadine Schmidt
- European Center for Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Mitko Mladenov
- Department of Fundamental and Applied Physiology, Russian National Research Medical University, Moscow, Russia.,Institute of Biology, Faculty of Natural Sciences and Mathematics, Ss Cyril and Methodius University, Skopje, Macedonia
| | - Rudolf Schubert
- European Center for Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Department of Physiology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
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13
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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] [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.
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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.
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14
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Serrano-Novillo C, Oliveras A, Ferreres JC, Condom E, Felipe A. Remodeling of Kv7.1 and Kv7.5 Expression in Vascular Tumors. Int J Mol Sci 2020; 21:ijms21176019. [PMID: 32825637 PMCID: PMC7503939 DOI: 10.3390/ijms21176019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/11/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022] Open
Abstract
Voltage-dependent potassium (Kv) channels contribute to the excitability of nerves and muscles. In addition, Kv participates in several cell functions, including cell cycle progression and proliferation. Kv channel remodeling has been associated with neoplastic cell growth and cancer. Kv7 channels are expressed in blood vessels, and they participate in the maintenance of vascular tone and are implicated in myocyte proliferation. Although evidence links Kv7 remodeling to different types of cancer, its expression in vascular tumors has never been studied. Endothelium-derived vascular neoplasms range from indolent lesions to highly aggressive and metastasizing cancers. Here, we show that Kv7.1 and Kv7.5 are evenly distributed in tunicas as well as the endothelium of healthy veins and arteries. The layered structure of vessels is lost in vascular tumors. By studying eight vascular tumors with different origins and characteristics, we found that Kv7.1 and Kv7.5 expression was changed in vascular cancers. While both channels were generally downregulated, Kv7.5 expression was clearly correlated with neoplastic malignancy. The vascular tumors did not contract; therefore, the role of Kv7 channels is probably related to proliferation rather than controlling vascular tone. Our results identify vascular Kv7 channels as targets for cancer detection and anticancer therapies.
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Affiliation(s)
- Clara Serrano-Novillo
- Molecular Physiology Laboratory, Department de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (C.S.-N.); (A.O.)
| | - Anna Oliveras
- Molecular Physiology Laboratory, Department de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (C.S.-N.); (A.O.)
| | - Joan Carles Ferreres
- Consorci Corporació Sanitària Parc Taulí-Parc Taulí Hospital Universitari, Universitat Autónoma de Barcelona, 08208 Sabadell, Spain;
| | - Enric Condom
- Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Universitari de Bellvitge, 08907 L’Hospitalet de Llobregat, Spain;
| | - Antonio Felipe
- Molecular Physiology Laboratory, Department de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (C.S.-N.); (A.O.)
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
- Correspondence: ; Tel.: +34-934034616; Fax: +34-934021559
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15
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Diniz AFA, Ferreira RC, de Souza ILL, da Silva BA. Ionic Channels as Potential Therapeutic Targets for Erectile Dysfunction: A Review. Front Pharmacol 2020; 11:1120. [PMID: 32848741 PMCID: PMC7396897 DOI: 10.3389/fphar.2020.01120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022] Open
Abstract
Erectile dysfunction (ED) is a prevalent condition, especially in men over 40 years old, characterized by the inability to obtain and/or maintain penile erection sufficient for satisfactory sexual intercourse. Several psychological and/or organic factors are involved in the etiopathogenesis of ED. In this context, we gathered evidence of the involvement of Large-conductance, Ca2+-activated K+ channels (BKCa), Small-conductance, Ca2+-activated K+ channels (SKCa), KCNQ-encoded voltage-dependent K+ channels (KV7), Transient Receptor Potential channels (TRP), and Calcium-activated Chloride channels (CaCC) dysfunctions on ED. In addition, the use of modulating agents of these channels are involved in relaxation of the cavernous smooth muscle cell and, consequent penile erection, suggesting that these channels are promising therapeutic targets for the treatment of erectile dysfunction.
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Affiliation(s)
- Anderson Fellyp Avelino Diniz
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - Rafael Carlos Ferreira
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - Iara Leão Luna de Souza
- Departamento de Ciências Biológicas e da Saúde, Universidade Estadual de Roraima, Boa Vista, Brazil
| | - Bagnólia Araújo da Silva
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Universidade Federal da Paraíba, João Pessoa, Brazil
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16
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Abstract
Kv7 channels (Kv7.1-7.5) are voltage-gated K+ channels that can be modulated by five β-subunits (KCNE1-5). Kv7.1-KCNE1 channels produce the slow-delayed rectifying K+ current, IKs, which is important during the repolarization phase of the cardiac action potential. Kv7.2-7.5 are predominantly neuronally expressed and constitute the muscarinic M-current and control the resting membrane potential in neurons. Kv7.1 produces drastically different currents as a result of modulation by KCNE subunits. This flexibility allows the Kv7.1 channel to have many roles depending on location and assembly partners. The pharmacological sensitivity of Kv7.1 channels differs from that of Kv7.2-7.5 and is largely dependent upon the number of β-subunits present in the channel complex. As a result, the development of pharmaceuticals targeting Kv7.1 is problematic. This review discusses the roles and the mechanisms by which different signaling pathways affect Kv7.1 and KCNE channels and could potentially provide different ways of targeting the channel.
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Affiliation(s)
- Emely Thompson
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
| | - Jodene Eldstrom
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
| | - David Fedida
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
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17
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Seo MS, An JR, Jung HS, Jung WK, Choi IW, Na SH, Park H, Bae YM, Park WS. The muscarinic receptor antagonist tolterodine inhibits voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells. Eur J Pharmacol 2020; 870:172921. [DOI: 10.1016/j.ejphar.2020.172921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/03/2019] [Accepted: 01/10/2020] [Indexed: 11/17/2022]
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18
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Zavaritskaya O, Dudem S, Ma D, Rabab KE, Albrecht S, Tsvetkov D, Kassmann M, Thornbury K, Mladenov M, Kammermeier C, Sergeant G, Mullins N, Wouappi O, Wurm H, Kannt A, Gollasch M, Hollywood MA, Schubert R. Vasodilation of rat skeletal muscle arteries by the novel BK channel opener GoSlo is mediated by the simultaneous activation of BK and K v 7 channels. Br J Pharmacol 2020; 177:1164-1186. [PMID: 31658366 PMCID: PMC7042121 DOI: 10.1111/bph.14910] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 09/27/2019] [Accepted: 10/01/2019] [Indexed: 01/17/2023] Open
Abstract
Background and Purpose BK channels play important roles in various physiological and pathophysiological processes and thus have been the target of several drug development programmes focused on creating new efficacious BK channel openers, such as the GoSlo‐SR compounds. However, the effect of GoSlo‐SR compounds on vascular smooth muscle has not been studied. Therefore, we tested the hypothesis that GoSlo‐SR compounds dilate arteries exclusively by activating BK channels. Experimental Approach Experiments were performed on rat Gracilis muscle, saphenous, mesenteric and tail arteries using isobaric and isometric myography, sharp microelectrodes, digital droplet PCR and the patch‐clamp technique. Key Results GoSlo‐SR compounds dilated isobaric and relaxed and hyperpolarised isometric vessel preparations and their effects were abolished after (a) functionally eliminating K+ channels by pre‐constriction with 50 mM KCl or (b) blocking all K+ channels known to be expressed in vascular smooth muscle. However, these effects were not blocked when BK channels were inhibited. Surprisingly, the Kv7 channel inhibitor XE991 reduced their effects considerably, but neither Kv1 nor Kv2 channel blockers altered the inhibitory effects of GoSlo‐SR. However, the combined blockade of BK and Kv7 channels abolished the GoSlo‐SR‐induced relaxation. GoSlo‐SR compounds also activated Kv7.4 and Kv7.5 channels expressed in HEK 293 cells. Conclusion and Implications This study shows that GoSlo‐SR compounds are effective relaxants in vascular smooth muscle and mediate their effects by a combined activation of BK and Kv7.4/Kv7.5 channels. Activation of Kv1, Kv2 or Kv7.1 channels or other vasodilator pathways seems not to be involved.
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Affiliation(s)
- Olga Zavaritskaya
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Srikanth Dudem
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Dongyu Ma
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Department of Cardiology, The First Affiliated Hospital of Anhui Medical University, Anhui, China
| | - Kaneez E Rabab
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Sarah Albrecht
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dmitry Tsvetkov
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
| | - Mario Kassmann
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
| | - Keith Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland.,Ion Channel Biotechnology Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Mitko Mladenov
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Institute of Biology, Faculty of Natural Sciences and Mathematics, Sts. Cyril and Methodius, University of Skopje, Skopje, Macedonia.,Department of Fundamental and Applied Physiology, Russian National Research Medical University, Moscow, Russia
| | - Claire Kammermeier
- Sanofi Diabetes Research, Industriepark Hoechst, Frankfurt am Main, Germany
| | - Gerard Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland.,Ion Channel Biotechnology Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Nicholas Mullins
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Ornella Wouappi
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Hannah Wurm
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Aimo Kannt
- Sanofi Diabetes Research, Industriepark Hoechst, Frankfurt am Main, Germany.,Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland.,Ion Channel Biotechnology Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Faculty of Medicine, Department of Physiology, Augsburg University, Augsburg, Germany
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19
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Abstract
Here, I recount some adventures that I and my colleagues have had over some 60 years since 1957 studying the effects of drugs and neurotransmitters on neuronal excitability and ion channel function, largely, but not exclusively, using sympathetic neurons as test objects. Studies include effects of centrally active drugs on sympathetic transmission; neuronal action and neuroglial uptake of GABA in the ganglia and brain; the action of muscarinic agonists on sympathetic neurons; the action of bradykinin on neuroblastoma-derived cells; and the identification of M-current as a target for muscarinic action, including experiments to determine its distribution, molecular composition, neurotransmitter sensitivity, and intracellular regulation by phospholipids and their hydrolysis products. Techniques used include electrophysiological recording (extracellular, intracellular microelectrode, whole-cell, and single-channel patch-clamp), autoradiography, messenger RNA and complementary DNA expression, antibody injection, antisense knockdown, and membrane-targeted lipidated peptides. I finish with some recollections about my scientific career, funding, and changes in laboratory life and pharmacology research over the past 60 years.
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Affiliation(s)
- David A. Brown
- Departments of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom
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20
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Liu R, Tzounopoulos T, Wipf P. Synthesis and Optimization of K v7 (KCNQ) Potassium Channel Agonists: The Role of Fluorines in Potency and Selectivity. ACS Med Chem Lett 2019; 10:929-935. [PMID: 31223450 DOI: 10.1021/acsmedchemlett.9b00097] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 05/08/2019] [Indexed: 12/18/2022] Open
Abstract
Based on the potent Kv7 agonist RL-81, we prepared new lead structures with greatly improved selectivity for Kv7.2/Kv7.3 over related potassium channels, i.e., Kv7.3/Kv7.5, Kv7.4, and Kv7.4/7.5. RL-36 and RL-12 maintain an agonist EC2x of ca. 1 μM on Kv7.2/Kv7.3 in a high-throughput assay on an automated electrophysiology platform in HEK293 cells but lack activity on Kv7.3/Kv7.5, Kv7.4, and Kv7.4/7.5, resulting in a selectivity index SI > 10. RL-56 is remarkably potent, EC2x 0.11 ± 0.02 μM, and still shows an SI = 2.5. We also identified analogues with significant selectivity for Kv7.4/Kv7.5 over Kv7.2/Kv7.3. The extensive use of fluorine in iterative core structure modifications highlights the versatility of these substituents, including F, CF3, and SF5, to span orders of magnitude of potency and selectivity in medicinal chemistry lead optimizations.
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Affiliation(s)
- Ruiting Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Thanos Tzounopoulos
- Department of Otolaryngology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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21
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Shvetsova AA, Gaynullina DK, Tarasova OS, Schubert R. Negative feedback regulation of vasocontraction by potassium channels in 10- to 15-day-old rats: Dominating role of K v 7 channels. Acta Physiol (Oxf) 2019; 225:e13176. [PMID: 30136434 DOI: 10.1111/apha.13176] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/11/2018] [Accepted: 08/20/2018] [Indexed: 12/26/2022]
Abstract
AIM Potassium channels are key regulators of smooth muscle membrane potential and arterial tone. However, the roles of potassium channels in vascular tone regulation in the systemic circulation during early postnatal development are poorly understood. Therefore, this study tested the hypothesis that the negative feedback regulation of vasocontraction by potassium channels changes during maturation. METHODS Experiments were performed on endothelium-denuded saphenous arteries from 10- to 15-day-old and 2- to 3-month-old male rats. Isometric force and membrane potential were recorded using wire myography and the sharp microelectrode technique respectively; mRNA and protein contents were determined by qPCR and Western blotting. RESULTS The effects of Kv 1, Kir and Kv 7 channel blockers (DPO-1, BaCl2 , XE991) on methoxamine-induced contraction were larger in arteries of 10- to 15-day-old compared to 2- to 3-month-old animals. In contrast, the BKC a channel blocker iberiotoxin had a stronger influence in 2- to 3- month-old rats. The effects of KATP and Kv 2 channel blockers (glibenclamide, stromatoxin) were not pronounced at both ages. The larger influence of Kv 7 and Kir channel blockade on arterial contraction in 10- to 15-day-old rats was associated with more prominent smooth muscle depolarization. The developmental alterations in potassium channel functioning were generally consistent with their mRNA and protein expression levels in arterial smooth muscle. CONCLUSION The negative feedback regulation of vasocontraction by potassium channels varies during maturation depending on the channel type. A dominating contribution of Kv 7 channels to the regulation of basal tone and agonist-induced contraction was observed in arteries of 10- to 15-day-old animals.
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Affiliation(s)
- Anastasia A. Shvetsova
- Centre for Biomedicine and Medical Technology Mannheim (CBTM); European Center of Angioscience (ECAS); Research Division Cardiovascular Physiology; Medical Faculty Mannheim; Heidelberg University; Heidelberg Germany
- Faculty of Biology; M.V. Lomonosov Moscow State University; Moscow Russia
- State Research Center of the Russian Federation - Institute for Biomedical Problems; Russian Academy of Sciences; Moscow Russia
| | - Dina K. Gaynullina
- Faculty of Biology; M.V. Lomonosov Moscow State University; Moscow Russia
- State Research Center of the Russian Federation - Institute for Biomedical Problems; Russian Academy of Sciences; Moscow Russia
- Department of Physiology; Russian National Research Medical University; Moscow Russia
| | - Olga S. Tarasova
- Faculty of Biology; M.V. Lomonosov Moscow State University; Moscow Russia
- State Research Center of the Russian Federation - Institute for Biomedical Problems; Russian Academy of Sciences; Moscow Russia
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim (CBTM); European Center of Angioscience (ECAS); Research Division Cardiovascular Physiology; Medical Faculty Mannheim; Heidelberg University; Heidelberg Germany
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22
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Wang L, Qiao GH, Hu HN, Gao ZB, Nan FJ. Discovery of Novel Retigabine Derivatives as Potent KCNQ4 and KCNQ5 Channel Agonists with Improved Specificity. ACS Med Chem Lett 2019; 10:27-33. [PMID: 30655942 DOI: 10.1021/acsmedchemlett.8b00315] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 12/19/2018] [Indexed: 12/22/2022] Open
Abstract
Recent research suggests that KCNQ isoforms, particularly the KCNQ4 and KCNQ5 subtypes expressed in smooth muscle cells, are involved in both establishing and maintaining resting membrane potentials and regulating smooth muscle contractility. Retigabine (RTG) is a first-in-class antiepileptic drug that potentiates neuronal KCNQ potassium channels, but poor subtype selectivity limits its further application as a pharmacological tool. In this study, we improved the subtype specificity of retigabine by altering the N-1/3 substituents and discovered several compounds that show better selectivity for KCNQ4 and KCNQ5 channels. Among these compounds, 10g is highly selective for KCNQ4 and KCNQ5 channels without potentiating KCNQ1 and KCNQ2 channels. These results are an advance in the exploration of small molecule modifiers that selectively activate different KCNQ isoforms. The developed compounds could also serve as new pharmacological tools for elucidating the function of KCNQ channels natively expressed in various tissues.
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Affiliation(s)
- Lei Wang
- State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, P. R. China
| | - Guan-Hua Qiao
- State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, P. R. China
| | - Hai-Ning Hu
- State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Zhao-Bing Gao
- State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Fa-Jun Nan
- State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
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23
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Jackson WF. K V channels and the regulation of vascular smooth muscle tone. Microcirculation 2018; 25. [PMID: 28985443 DOI: 10.1111/micc.12421] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/01/2017] [Indexed: 12/31/2022]
Abstract
VSMCs in resistance arteries and arterioles express a diverse array of KV channels with members of the KV 1, KV 2 and KV 7 families being particularly important. Members of the KV channel family: (i) are highly expressed in VSMCs; (ii) are active at the resting membrane potential of VSMCs in vivo (-45 to -30 mV); (iii) contribute to the negative feedback regulation of VSMC membrane potential and myogenic tone; (iv) are activated by cAMP-related vasodilators, hydrogen sulfide and hydrogen peroxide; (v) are inhibited by increases in intracellular Ca2+ and vasoconstrictors that signal through Gq -coupled receptors; (vi) are involved in the proliferative phenotype of VSMCs; and (vii) are modulated by diseases such as hypertension, obesity, the metabolic syndrome and diabetes. Thus, KV channels participate in every aspect of the regulation of VSMC function in both health and disease.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, USA
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24
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Schmid J, Müller B, Heppeler D, Gaynullina D, Kassmann M, Gagov H, Mladenov M, Gollasch M, Schubert R. The Unexpected Role of Calcium-Activated Potassium Channels: Limitation of NO-Induced Arterial Relaxation. J Am Heart Assoc 2018; 7:e007808. [PMID: 29574460 PMCID: PMC5907584 DOI: 10.1161/jaha.117.007808] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/14/2018] [Indexed: 11/24/2022]
Abstract
BACKGROUND Multiple studies have shown that an NO-induced activation of vascular smooth muscle BK channels contributes to the NO-evoked dilation in many blood vessels. In vivo, NO is released continuously. NO attenuates vessel constrictions and, therefore, exerts an anticontractile effect. It is unknown whether the anticontractile effect of continuously present NO is mediated by BK channels. METHODS AND RESULTS This study tested the hypothesis that BK channels mediate the vasodilatory effect of continuously present NO. Experiments were performed on rat and mouse tail and rat saphenous arteries using isometric myography and FURA-2 fluorimetry. Continuously present NO donors, as well as endogenous NO, attenuated methoxamine-induced vasoconstrictions. This effect was augmented in the presence of the BK channel blocker iberiotoxin. Moreover, the contractile effect of iberiotoxin was reduced in the presence of NO donors. The effect of the NO donor sodium nitroprusside was abolished by an NO scavenger and by a guanylyl cyclase inhibitor. In addition, the effect of sodium nitroprusside was reduced considerably by a protein kinase G inhibitor, but was not altered by inhibition of H2S generation. Sodium nitroprusside attenuated the intracellular calcium concentration response to methoxamine. Furthermore, sodium nitroprusside strongly reduced methoxamine-induced calcium influx, which depends entirely on L-type calcium channels. It did not affect methoxamine-induced calcium release. CONCLUSIONS In summary, this study demonstrates the following: (1) continuously present NO evokes a strong anticontractile effect on rat and mouse arteries; (2) the iberiotoxin-induced augmentation of the effect of NO is associated with an NO-induced reduction of the effect of iberiotoxin; and (3) NO evoked a reduction of calcium influx via L-type calcium channels.
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Affiliation(s)
- Johannes Schmid
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Bettina Müller
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - David Heppeler
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dina Gaynullina
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Faculty of Biology, M.V. Lomonosov, Moscow State University, Moscow, Russia
- Department of Physiology, Russian National Research Medical University, Moscow, Russia
| | - Mario Kassmann
- Experimental and Clinical Research Center, a joint cooperation between the, Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Hristo Gagov
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Mitko Mladenov
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Maik Gollasch
- Experimental and Clinical Research Center, a joint cooperation between the, Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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25
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Berg T. Kv7(KCNQ)-K +-Channels Influence Total Peripheral Resistance in Female but Not Male Rats, and Hamper Catecholamine Release in Hypertensive Rats of Both Sexes. Front Physiol 2018. [PMID: 29515459 PMCID: PMC5826282 DOI: 10.3389/fphys.2018.00117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
K+-channels of the Kv7/KCNQ-family hyperpolarize and stabilize excitable cells such as autonomic neurons and vascular smooth muscle cells (VSMC). Kv7 may therefore play a role in blood pressure (BP) homeostasis, and prevent a high total peripheral vascular resistance (TPR), a hallmark of hypertensive disease. The present study analyzed if Kv7 channels influence catecholamine release and TPR in normotensive (WKY) and spontaneously hypertensive rats (SHR), and if they may contribute to the antihypertensive protection seen in young, female SHR. Tyramine-stimulated norepinephrine release evokes an adrenergic cardiovascular response, and also allows modulation of release to be reflected in the overflow to plasma. The experiment itself activated some secretion of epinephrine. The results show: (1) XE-991 (Kv7.1-7.4-inhibitor), but not chromanol 293B (Kv7.1-inhibitor), increased tyramine-stimulated norepinephrine overflow and epinephrine secretion in both sexes in SHR, but not WKY. (2) Surprisingly, the Kv7-openers retigabine (Kv7.2-7.5) and ICA-27243 (Kv7.2-7.3-preferring) increased catecholamine release in female SHR. (3) The rise in TPR following tyramine-stimulated norepinephrine release was increased by XE-991 but not chromanol in the female WKY only. (4) Retigabine and ICA-27243 reduced the TPR-response to tyramine in the female SHR only. These results suggested: (1) Up-regulation of Kv7.2-7.3 function in sympathetic neurons and chromaffin cells hampered catecholamine release in SHR of both sexes. (2) The increase catecholamine release observed after channel openers in the female SHR may possibly involve reduced transmission in cholinergic neurons which hamper catecholamine release. These two mechanisms may serve to counter-act the hyperadrenergic state in SHR. (3) Kv7.4, most likely in the vasculature, opposed the tension-response to norepinephrine in the female WKY. (4) Vascular Kv7.4-7.5 could be stimulated and then opposed norepinephrine-induced vasoconstriction in the female SHR. (5) Vascular Kv7 channels did not counter-act norepinephrine induced vasoconstriction in male rats, possibly due to different Kv7 channel regulation. Kv7 channels may represent a novel target for antihypertensive therapy.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute for Basic Medical Sciences, University of Oslo, Oslo, Norway
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26
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Brown DA. Regulation of neural ion channels by muscarinic receptors. Neuropharmacology 2017; 136:383-400. [PMID: 29154951 DOI: 10.1016/j.neuropharm.2017.11.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 10/26/2017] [Accepted: 11/13/2017] [Indexed: 12/20/2022]
Abstract
The excitable behaviour of neurons is determined by the activity of their endogenous membrane ion channels. Since muscarinic receptors are not themselves ion channels, the acute effects of muscarinic receptor stimulation on neuronal function are governed by the effects of the receptors on these endogenous neuronal ion channels. This review considers some principles and factors determining the interaction between subtypes and classes of muscarinic receptors with neuronal ion channels, and summarizes the effects of muscarinic receptor stimulation on a number of different channels, the mechanisms of receptor - channel transduction and their direct consequences for neuronal activity. Ion channels considered include potassium channels (voltage-gated, inward rectifier and calcium activated), voltage-gated calcium channels, cation channels and chloride channels. This article is part of the Special Issue entitled 'Neuropharmacology on Muscarinic Receptors'.
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Affiliation(s)
- David A Brown
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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27
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Salomonsson M, Brasen JC, Sorensen CM. Role of renal vascular potassium channels in physiology and pathophysiology. Acta Physiol (Oxf) 2017; 221:14-31. [PMID: 28371470 DOI: 10.1111/apha.12882] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/10/2016] [Accepted: 03/22/2017] [Indexed: 12/31/2022]
Abstract
The control of renal vascular tone is important for the regulation of salt and water balance, blood pressure and the protection against damaging elevated glomerular pressure. The K+ conductance is a major factor in the regulation of the membrane potential (Vm ) in vascular smooth muscle (VSMC) and endothelial cells (EC). The vascular tone is controlled by Vm via its effect on the opening probability of voltage-operated Ca2+ channels (VOCC) in VSMC. When K+ conductance increases Vm becomes more negative and vasodilation follows, while deactivation of K+ channels leads to depolarization and vasoconstriction. K+ channels in EC indirectly participate in the control of vascular tone by endothelium-derived vasodilation. Therefore, by regulating the tone of renal resistance vessels, K+ channels have a potential role in the control of fluid homoeostasis and blood pressure as well as in the protection of the renal parenchyma. The main classes of K+ channels (calcium activated (KCa ), inward rectifier (Kir ), voltage activated (Kv ) and ATP sensitive (KATP )) have been found in the renal vessels. In this review, we summarize results available in the literature and our own studies in the field. We compare the ambiguous in vitro and in vivo results. We discuss the role of single types of K+ channels and the integrated function of several classes. We also deal with the possible role of renal vascular K+ channels in the pathophysiology of hypertension, diabetes mellitus and sepsis.
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Affiliation(s)
| | - J. C. Brasen
- Department of Electrical Engineering; Technical University of Denmark; Kgs. Lyngby Denmark
| | - C. M. Sorensen
- Department of Biomedical Sciences; Division of Renal and Vascular Physiology; University of Copenhagen; Copenhagen Denmark
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28
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Zimmer J, Takahashi T, Hofmann AD, Puri P. Downregulation of KCNQ5 expression in the rat pulmonary vasculature of nitrofen-induced congenital diaphragmatic hernia. J Pediatr Surg 2017; 52:702-705. [PMID: 28189443 DOI: 10.1016/j.jpedsurg.2017.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 01/23/2017] [Indexed: 12/17/2022]
Abstract
PURPOSE Pulmonary hypertension (PH) is a common complication of congenital diaphragmatic hernia (CDH). Voltage-gated potassium channels KCNQ1, KCNQ4, and KCNQ5 are expressed by rodent pulmonary artery smooth muscle cells, contributing to their vascular tone. We hypothesized that KCNQ1, KCNQ4, and KCNQ5 expression is altered in the pulmonary vasculature of nitrofen-induced CDH rats. METHODS After ethical approval (REC913b), time-pregnant rats received nitrofen or vehicle on gestational day (D)9. D21 fetuses were divided into CDH and control group (n=22). QRT-PCR and western blotting were performed to determine gene and protein expression of KCNQ1, KCNQ4, and KCNQ5. Confocal microscopy was used to detect these proteins in the pulmonary vasculature. RESULTS Relative mRNA level of KCNQ5 (p=0.025) was significantly downregulated in CDH lungs compared to controls. KCNQ1 (p=0.052) and KCNQ4 (p=0.574) expression was not altered. Western blotting confirmed the decreased pulmonary KCNQ5 protein expression in CDH lungs. Confocal-microscopy detected a markedly diminished KCNQ5 expression in pulmonary vasculature of CDH fetuses. CONCLUSIONS Downregulated pulmonary expression of KCNQ5 in CDH lungs suggests that this potassium channel may play an important role in the development of PH in this model. KCNQ5 channel activator drugs may be a potential therapeutic target for the treatment of PH in CDH. LEVEL OF EVIDENCE 2b (Centre for Evidence-Based Medicine, Oxford).
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Affiliation(s)
- Julia Zimmer
- National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Gate 5, Dublin 12, Dublin, Ireland
| | - Toshiaki Takahashi
- National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Gate 5, Dublin 12, Dublin, Ireland
| | - Alejandro D Hofmann
- Department of Pediatric Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Prem Puri
- National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Gate 5, Dublin 12, Dublin, Ireland; School of Medicine and Medical Science and Conway Institute of Biomedical Research, University College Dublin, Belfield, Dublin 4, Dublin, Ireland.
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29
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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30
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Tsvetkov D, Kaßmann M, Tano JY, Chen L, Schleifenbaum J, Voelkl J, Lang F, Huang Y, Gollasch M. Do K V 7.1 channels contribute to control of arterial vascular tone? Br J Pharmacol 2016; 174:150-162. [PMID: 28000293 DOI: 10.1111/bph.13665] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 10/11/2016] [Accepted: 10/28/2016] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND AND PURPOSE KV 7.1 voltage-gated potassium channels are expressed in vascular smooth muscle cells (VSMC) of diverse arteries, including mesenteric arteries. Based on pharmacological evidence using R-L3 (KV 7.1 channel opener), HMR1556, chromanol 293B (KV 7.1 channel blockers), stimulation of these channels has been suggested to evoke profound relaxation in various vascular beds of rats. However, the specificity of these drugs in vivo is uncertain. EXPERIMENTAL APPROACH We used Kcnq1-/- mice and pharmacological tools to determine whether KV 7.1 channels play a role in the regulation of arterial tone. KEY RESULTS R-L3 produced similar concentration-dependent relaxations (EC50 ~ 1.4 μM) of arteries from wild-type (Kcnq1+/+ ) and Kcnq1-/- mice, pre-contracted with either phenylephrine or 60 mM KCl. This relaxation was not affected by 10 μM chromanol 293B, 10 μM HMR1556 or 30 μM XE991 (pan-KV 7 channel blocker). The anti-contractile effects of the perivascular adipose tissue (PVAT) were normal in Kcnq1-/- arteries. Chromanol 293B and HMR1556 did not affect the anti-contractile effects of (PVAT). Isolated VSMCs from Kcnq1-/- mice exhibited normal peak KV currents. The KV 7.2-5 channel opener retigabine caused similar relaxations in Kcnq1-/- and wild-type vessels. CONCLUSION AND IMPLICATIONS We conclude that KV 7.1 channels were apparently not involved in the control of arterial tone by α1 -adrenoceptor agonists and PVAT. In addition, R-L3 is an inappropriate pharmacological tool for studying the function of native vascular KV 7.1 channels in mice.
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Affiliation(s)
- Dmitry Tsvetkov
- Experimental and Clinical Research Center (ECRC), A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Mario Kaßmann
- Experimental and Clinical Research Center (ECRC), A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Jean-Yves Tano
- Experimental and Clinical Research Center (ECRC), A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Lan Chen
- Experimental and Clinical Research Center (ECRC), A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Xiamen Zhongshan Hospital, Xiamen University, Xiamen, China
| | - Johanna Schleifenbaum
- Experimental and Clinical Research Center (ECRC), A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Jakob Voelkl
- Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Tübingen, Germany
| | - Florian Lang
- Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Tübingen, Germany
| | - Yu Huang
- School of Biomedical Sciences, 223A, Lo Kwee-Seong Integrated Biomedical Sciences Building, Area 39, Chinese University of Hong Kong, Sha Tin, Hong Kong
| | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC), A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Medical Clinic for Nephrology and Internal Intensive Care, Campus Virchow, Charité University Medicine, Berlin, Germany
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31
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Zhang X, An H, Li J, Zhang Y, Liu Y, Jia Z, Zhang W, Chu L, Zhang H. Selective activation of vascular K v 7.4/K v 7.5 K + channels by fasudil contributes to its vasorelaxant effect. Br J Pharmacol 2016; 173:3480-3491. [PMID: 27677924 DOI: 10.1111/bph.13639] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 09/13/2016] [Accepted: 09/15/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Kv 7 (Kv 7.1-7.5) channels play an important role in the regulation of neuronal excitability and the cardiac action potential. Growing evidence suggests Kv 7.4/Kv 7.5 channels play a crucial role in regulating vascular smooth muscle contractility. Most of the reported Kv 7 openers have shown poor selectivity across these five subtypes. In this study, fasudil - a drug used for cerebral vasospasm - has been found to be a selective opener of Kv 7.4/Kv 7.5 channels. EXPERIMENTAL APPROACH A perforated whole-cell patch technique was used to record the currents and membrane potential. Homology modelling and a docking technique were used to investigate the interaction between fasudil and the Kv 7.4 channel. An isometric tension recording technique was used to assess the vascular tension. KEY RESULTS Fasudil selectively and potently enhanced Kv 7.4 and Kv 7.4/Kv 7.5 currents expressed in HEK293 cells, and shifted the voltage-dependent activation curve in a more negative direction. Fasudil did not affect either Kv 7.2 and Kv 7.2/Kv 7.3 currents expressed in HEK293 cells, the native neuronal M-type K+ currents, or the resting membrane potential in small rat dorsal root ganglia neurons. The Val248 in S5 and Ile308 in S6 segment of Kv 7.4 were critical for this activating effect of fasudil. Fasudil relaxed precontracted rat small arteries in a concentration-dependent fashion; this effect was antagonized by the Kv 7 channel blocker XE991. CONCLUSIONS AND IMPLICATIONS These results suggest that fasudil is a selective Kv 7.4/Kv 7.5 channel opener and provide a new dimension for developing selective Kv 7 modulators and a new prospective for the use, action and mechanism of fasudil.
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Affiliation(s)
- Xuan Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, China.,Department of Pharmacology, Institution of Chinese Integrative Medicine, Hebei Medical University, Shijiazhuang, China
| | - Hailong An
- Key Laboratory of Molecular Biophysics, Hebei Province; Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Junwei Li
- Key Laboratory of Molecular Biophysics, Hebei Province; Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Yuanyuan Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Yang Liu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Zhanfeng Jia
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Wei Zhang
- Department of Pharmacology, Institution of Chinese Integrative Medicine, Hebei Medical University, Shijiazhuang, China
| | - Li Chu
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
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32
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KV7 channels in the human detrusor: channel modulator effects and gene and protein expression. Naunyn Schmiedebergs Arch Pharmacol 2016; 390:127-137. [DOI: 10.1007/s00210-016-1312-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/11/2016] [Indexed: 12/13/2022]
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33
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Greene DL, Hoshi N. Modulation of Kv7 channels and excitability in the brain. Cell Mol Life Sci 2016; 74:495-508. [PMID: 27645822 DOI: 10.1007/s00018-016-2359-y] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/25/2016] [Accepted: 09/06/2016] [Indexed: 11/26/2022]
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.
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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.
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Potassium Channels in Regulation of Vascular Smooth Muscle Contraction and Growth. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:89-144. [PMID: 28212804 DOI: 10.1016/bs.apha.2016.07.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Potassium channels importantly contribute to the regulation of vascular smooth muscle (VSM) contraction and growth. They are the dominant ion conductance of the VSM cell membrane and importantly determine and regulate membrane potential. Membrane potential, in turn, regulates the open-state probability of voltage-gated Ca2+ channels (VGCC), Ca2+ influx through VGCC, intracellular Ca2+, and VSM contraction. Membrane potential also affects release of Ca2+ from internal stores and the Ca2+ sensitivity of the contractile machinery such that K+ channels participate in all aspects of regulation of VSM contraction. Potassium channels also regulate proliferation of VSM cells through membrane potential-dependent and membrane potential-independent mechanisms. VSM cells express multiple isoforms of at least five classes of K+ channels that contribute to the regulation of contraction and cell proliferation (growth). This review will examine the structure, expression, and function of large conductance, Ca2+-activated K+ (BKCa) channels, intermediate-conductance Ca2+-activated K+ (KCa3.1) channels, multiple isoforms of voltage-gated K+ (KV) channels, ATP-sensitive K+ (KATP) channels, and inward-rectifier K+ (KIR) channels in both contractile and proliferating VSM cells.
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Haick JM, Byron KL. Novel treatment strategies for smooth muscle disorders: Targeting Kv7 potassium channels. Pharmacol Ther 2016; 165:14-25. [PMID: 27179745 DOI: 10.1016/j.pharmthera.2016.05.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Smooth muscle cells provide crucial contractile functions in visceral, vascular, and lung tissues. The contractile state of smooth muscle is largely determined by their electrical excitability, which is in turn influenced by the activity of potassium channels. The activity of potassium channels sustains smooth muscle cell membrane hyperpolarization, reducing cellular excitability and thereby promoting smooth muscle relaxation. Research over the past decade has indicated an important role for Kv7 (KCNQ) voltage-gated potassium channels in the regulation of the excitability of smooth muscle cells. Expression of multiple Kv7 channel subtypes has been demonstrated in smooth muscle cells from viscera (gastrointestinal, bladder, myometrial), from the systemic and pulmonary vasculature, and from the airways of the lung, from multiple species, including humans. A number of clinically used drugs, some of which were developed to target Kv7 channels in other tissues, have been found to exert robust effects on smooth muscle Kv7 channels. Functional studies have indicated that Kv7 channel activators and inhibitors have the ability to relax and contact smooth muscle preparations, respectively, suggesting a wide range of novel applications for the pharmacological tool set. This review summarizes recent findings regarding the physiological functions of Kv7 channels in smooth muscle, and highlights potential therapeutic applications based on pharmacological targeting of smooth muscle Kv7 channels throughout the body.
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Affiliation(s)
- Jennifer M Haick
- Department of Molecular Pharmacology & Therapeutics, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Kenneth L Byron
- Department of Molecular Pharmacology & Therapeutics, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA.
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Kumar M, Reed N, Liu R, Aizenman E, Wipf P, Tzounopoulos T. Synthesis and Evaluation of Potent KCNQ2/3-Specific Channel Activators. Mol Pharmacol 2016; 89:667-77. [PMID: 27005699 DOI: 10.1124/mol.115.103200] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/21/2016] [Indexed: 12/14/2022] Open
Abstract
KQT-like subfamily (KCNQ) channels are voltage-gated, noninactivating potassium ion channels, and their down-regulation has been implicated in several hyperexcitability-related disorders, including epilepsy, neuropathic pain, and tinnitus. Activators of these channels reduce the excitability of central and peripheral neurons, and, as such, have therapeutic utility. Here, we synthetically modified several moieties of the KCNQ2-5 channel activator retigabine, an anticonvulsant approved by the U.S. Food and Drug Administration. By introducing a CF3-group at the 4-position of the benzylamine moiety, combined with a fluorine atom at the 3-position of the aniline ring, we generated Ethyl (2-amino-3-fluoro-4-((4-(trifluoromethyl)benzyl)amino)phenyl)carbamate (RL648_81), a new KCNQ2/3-specific activator that is >15 times more potent and also more selective than retigabine. We suggest that RL648_81 is a promising clinical candidate for treating or preventing neurologic disorders associated with neuronal hyperexcitability.
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Affiliation(s)
- Manoj Kumar
- Department of Otolaryngology, School of Medicine (M.K., T.T.); Department of Chemistry (N.R., R.L., P.W.); Department of Neurobiology (E.A., T.T.); and Pittsburgh Institute for Neurodegenerative Diseases, School of Medicine (E.A.), University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Nicholas Reed
- Department of Otolaryngology, School of Medicine (M.K., T.T.); Department of Chemistry (N.R., R.L., P.W.); Department of Neurobiology (E.A., T.T.); and Pittsburgh Institute for Neurodegenerative Diseases, School of Medicine (E.A.), University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ruiting Liu
- Department of Otolaryngology, School of Medicine (M.K., T.T.); Department of Chemistry (N.R., R.L., P.W.); Department of Neurobiology (E.A., T.T.); and Pittsburgh Institute for Neurodegenerative Diseases, School of Medicine (E.A.), University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Elias Aizenman
- Department of Otolaryngology, School of Medicine (M.K., T.T.); Department of Chemistry (N.R., R.L., P.W.); Department of Neurobiology (E.A., T.T.); and Pittsburgh Institute for Neurodegenerative Diseases, School of Medicine (E.A.), University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Peter Wipf
- Department of Otolaryngology, School of Medicine (M.K., T.T.); Department of Chemistry (N.R., R.L., P.W.); Department of Neurobiology (E.A., T.T.); and Pittsburgh Institute for Neurodegenerative Diseases, School of Medicine (E.A.), University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thanos Tzounopoulos
- Department of Otolaryngology, School of Medicine (M.K., T.T.); Department of Chemistry (N.R., R.L., P.W.); Department of Neurobiology (E.A., T.T.); and Pittsburgh Institute for Neurodegenerative Diseases, School of Medicine (E.A.), University of Pittsburgh, Pittsburgh, Pennsylvania
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Zhang Y, Chu X, Liu L, Zhang N, Guo H, Yang F, Liu Z, Dong Y, Bao Y, Zhang X, Zhang J. Tannic acid activates the Kv7.4 and Kv7.3/7.5 K+ channels expressed in HEK293 cells and reduces tension in the rat mesenteric arteries. J Pharm Pharmacol 2016; 68:494-502. [PMID: 26969140 DOI: 10.1111/jphp.12527] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 01/14/2016] [Indexed: 12/13/2022]
Abstract
Abstract
Objectives
This study investigated the effect of tannic acid (TA), a plant-derived hydrolyzable polyphenol, on Kv7.4 and Kv7.5 K+ channels and rat mesenteric artery.
Methods
Whole-cell patch clamp experiments were used to record the Kv7.4 and Kv7.3/7.5 K+ currents expressed in HEK293 cells; and the tension changes of mesenteric arteries isolated from rats were recorded using small vessel myography apparatus.
Key findings
Tannic acid increases the Kv7.4 and Kv7.3/7.5 K+ currents in a concentration-dependent manner (median effective concentration (EC50) = 27.3 ± 3.6 μm and EC50 = 23.1 ± 3.9 μm, respectively). In addition, 30 μm TA shifts the G–V curve of Kv7.4 and Kv7.3/7.5 K+ currents to the left by 14.18 and 25.24 mV, respectively, and prolongs the deactivation time constants by 184.44 and 154.77 ms, respectively. Moreover, TA relaxes the vascular tension of rat mesenteric arteries in a concentration-dependent manner (half inhibitory concentration (IC50) = 148.7 ± 13.4 μm).
Conclusion
These results confirms the vasodilatory effects of TA on rat mesenteric artery and the activating effects on the Kv7.4 and Kv7.3/7.5 K+ channels, which may be a mechanism to explain the vasodilatory effect and this mechanism can be used in the research of antihypertension.
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Affiliation(s)
- Yuanyuan Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Xi Chu
- Department of Pharmacy, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Ling Liu
- Department of Pharmacy, Maternal and Child Health Hospital, Tangshan, Hebei, China
| | - Nan Zhang
- Vascular Surgery, The East Branch of Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Hui Guo
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Fan Yang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Zhenyi Liu
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Yongsheng Dong
- Intensive Care Unit, Air Force General Hospital, Beijing, Jiangsu, China
| | - Yifan Bao
- Key Laboratory of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Xuan Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Jianping Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
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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] [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.
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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:
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Zagorchev P, Apostolova E, Kokova V, Peychev L. Activation of KCNQ channels located on the skeletal muscle membrane by retigabine and its influence on the maximal muscle force in rat muscle strips. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2016; 389:439-46. [PMID: 26815201 DOI: 10.1007/s00210-016-1211-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/14/2016] [Indexed: 10/22/2022]
Abstract
Retigabine is a new antiepileptic drug with the main mechanism of action: activation of voltage-gated potassium channels (Kv7) represented in many tissues including the excitable cells-neuronal and muscular. The aim of this article is to determine the role of potassium channels located on the skeletal muscle membrane in the in vivo and in vitro reduction of muscle contractile activity induced by retigabine. We studied the effects of retigabine on the motor function in vivo using a bar holding test and exploratory activity using open field test in rats. Electrical field stimulation (EFS) was applied to skeletal muscle strips in vitro in order to evaluate muscular activity. We registered a significant decrease in the muscle tone and exploratory activity of rats, treated orally with 60 mg/kg bw retigabine. In vitro experiments showed decrease in the maximal muscle force of strips in the presence of retigabine in the medium after both indirect (nerve-like) and direct (muscle-like) stimulation. The effects were fully antagonized by XE-991 (Kv7 channel blocker), which supports our hypothesis about the relation between these types of potassium channels and the observed change in the muscle force. Based on these results, we can conclude that skeletal muscle Kv7 channels play a significant role in the myorelaxation and reduced muscle force registered after treatment with Kv7 channels openers (e.g., retigabine). The hyperpolarization of skeletal muscle membrane caused by accelerated K(+) efflux may be the underlying cause for the effect of retigabine on the muscle tone.
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Affiliation(s)
- P Zagorchev
- Department of Biophysics, Faculty of Pharmacy, Medical University-Plovdiv, Vasil Aprilov Str. 15A, 4000, Plovdiv, Bulgaria
| | - E Apostolova
- Department of Pharmacology and Drug Toxicology, Faculty of Pharmacy, Medical University-Plovdiv, Vasil Aprilov Str. 15A, 4000, Plovdiv, Bulgaria.
| | - V Kokova
- Department of Pharmacology and Drug Toxicology, Faculty of Pharmacy, Medical University-Plovdiv, Vasil Aprilov Str. 15A, 4000, Plovdiv, Bulgaria
| | - L Peychev
- Department of Pharmacology and Drug Toxicology, Faculty of Pharmacy, Medical University-Plovdiv, Vasil Aprilov Str. 15A, 4000, Plovdiv, Bulgaria
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Potent KCNQ2/3-specific channel activator suppresses in vivo epileptic activity and prevents the development of tinnitus. J Neurosci 2015; 35:8829-42. [PMID: 26063916 DOI: 10.1523/jneurosci.5176-14.2015] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Voltage-gated Kv7 (KCNQ) channels are voltage-dependent potassium channels that are activated at resting membrane potentials and therefore provide a powerful brake on neuronal excitability. Genetic or experience-dependent reduction of KCNQ2/3 channel activity is linked with disorders that are characterized by neuronal hyperexcitability, such as epilepsy and tinnitus. Retigabine, a small molecule that activates KCNQ2-5 channels by shifting their voltage-dependent opening to more negative voltages, is an US Food and Drug Administration (FDA) approved anti-epileptic drug. However, recently identified side effects have limited its clinical use. As a result, the development of improved KCNQ2/3 channel activators is crucial for the treatment of hyperexcitability-related disorders. By incorporating a fluorine substituent in the 3-position of the tri-aminophenyl ring of retigabine, we synthesized a small-molecule activator (SF0034) with novel properties. Heterologous expression of KCNQ2/3 channels in HEK293T cells showed that SF0034 was five times more potent than retigabine at shifting the voltage dependence of KCNQ2/3 channels to more negative voltages. Moreover, unlike retigabine, SF0034 did not shift the voltage dependence of either KCNQ4 or KCNQ5 homomeric channels. Conditional deletion of Kcnq2 from cerebral cortical pyramidal neurons showed that SF0034 requires the expression of KCNQ2/3 channels for reducing the excitability of CA1 hippocampal neurons. Behavioral studies demonstrated that SF0034 was a more potent and less toxic anticonvulsant than retigabine in rodents. Furthermore, SF0034 prevented the development of tinnitus in mice. We propose that SF0034 provides, not only a powerful tool for investigating ion channel properties, but, most importantly, it provides a clinical candidate for treating epilepsy and preventing tinnitus.
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Salomonsson M, Brasen JC, Braunstein TH, Hagelqvist P, Holstein-Rathlou NH, Sorensen CM. K(V)7.4 channels participate in the control of rodent renal vascular resting tone. Acta Physiol (Oxf) 2015; 214:402-14. [PMID: 25965962 DOI: 10.1111/apha.12525] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/19/2015] [Accepted: 05/06/2015] [Indexed: 01/07/2023]
Abstract
AIM We tested the hypothesis that K(V)7 channels contribute to basal renal vascular tone and that they participate in agonist-induced renal vasoconstriction or vasodilation. METHODS KV 7 channel subtypes in renal arterioles were characterized by immunofluorescence. Renal blood flow (RBF) was measured using an ultrasonic flow probe. The isometric tension of rat interlobar arteries was examined in a wire myograph. Mice afferent arteriolar diameter was assessed utilizing the perfused juxtamedullary nephron technique. RESULTS Immunofluorescence revealed that K(V)7.4 channels were expressed in rat afferent arterioles. The K(V)7 blocker XE991 dose-dependently increased the isometric tension of rat interlobar arteries and caused a small (approx. 4.5%) RBF reduction in vivo. Nifedipine abolished these effects. Likewise, XE991 reduced mouse afferent arteriolar diameter by approx. 5%. The K(V)7.2-5 stimulator flupirtine dose-dependently relaxed isolated rat interlobar arteries and increased (approx. 5%) RBF in vivo. The RBF responses to NE or Ang II administration were not affected by pre-treatment with XE991 or flupirtine. XE991 pre-treatment caused a minor augmentation of the acetylcholine-induced increase in RBF, while flupirtine pre-treatment did not affect this response. CONCLUSION It is concluded that K(V)7 channels, via nifedipine sensitive channels, have a role in the regulation of basal renal vascular tone. There is no indication that K(V)7 channels have an effect on agonist-induced renal vasoconstriction while there is a small effect on acetylcholine-induced vasodilation.
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Affiliation(s)
- M. Salomonsson
- Division of Renal and Vascular Physiology; Department of Biomedical Sciences; University of Copenhagen; Copenhagen Denmark
| | - J. C. Brasen
- Division of Renal and Vascular Physiology; Department of Biomedical Sciences; University of Copenhagen; Copenhagen Denmark
- Biomedical Engineering; Department of Electrical Engineering; Technical University of Denmark; Lyngby Denmark
| | - T. H. Braunstein
- Danish National Research Foundation Center for Cardiac Arrhythmia; University of Copenhagen; Copenhagen Denmark
| | - P. Hagelqvist
- Division of Renal and Vascular Physiology; Department of Biomedical Sciences; University of Copenhagen; Copenhagen Denmark
| | - N.-H. Holstein-Rathlou
- Division of Renal and Vascular Physiology; Department of Biomedical Sciences; University of Copenhagen; Copenhagen Denmark
- Danish National Research Foundation Center for Cardiac Arrhythmia; University of Copenhagen; Copenhagen Denmark
| | - C. M. Sorensen
- Division of Renal and Vascular Physiology; Department of Biomedical Sciences; University of Copenhagen; Copenhagen Denmark
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Provence A, Malysz J, Petkov GV. The Novel KV7.2/KV7.3 Channel Opener ICA-069673 Reveals Subtype-Specific Functional Roles in Guinea Pig Detrusor Smooth Muscle Excitability and Contractility. J Pharmacol Exp Ther 2015; 354:290-301. [PMID: 26087697 DOI: 10.1124/jpet.115.225268] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/17/2015] [Indexed: 12/20/2022] Open
Abstract
The physiologic roles of voltage-gated KV7 channel subtypes (KV7.1-KV7.5) in detrusor smooth muscle (DSM) are poorly understood. Here, we sought to elucidate the functional roles of KV7.2/KV7.3 channels in guinea pig DSM excitability and contractility using the novel KV7.2/KV7.3 channel activator ICA-069673 [N-(2-chloro-5-pyrimidinyl)-3,4-difluorobenzamide]. We employed a multilevel experimental approach using Western blot analysis, immunocytochemistry, isometric DSM tension recordings, fluorescence Ca(2+) imaging, and perforated whole-cell patch-clamp electrophysiology. Western blot experiments revealed the protein expression of KV7.2 and KV7.3 channel subunits in DSM tissue. In isolated DSM cells, immunocytochemistry with confocal microscopy further confirmed protein expression for KV7.2 and KV7.3 channel subunits, where they localize within the vicinity of the cell membrane. ICA-069673 inhibited spontaneous phasic, pharmacologically induced, and nerve-evoked contractions in DSM isolated strips in a concentration-dependent manner. The inhibitory effects of ICA-069673 on DSM spontaneous phasic and tonic contractions were abolished in the presence of the KV7 channel inhibitor XE991 [10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone dihydrochloride]. Under conditions of elevated extracellular K(+) (60 mM), the effects of ICA-069673 on DSM tonic contractions were significantly attenuated. ICA-069673 decreased the global intracellular Ca(2+) concentration in DSM cells, an effect blocked by the L-type Ca(2+) channel inhibitor nifedipine. ICA-069673 hyperpolarized the membrane potential and inhibited spontaneous action potentials of isolated DSM cells, effects that were blocked in the presence of XE991. In conclusion, using the novel KV7.2/KV7.3 channel activator ICA-069673, this study provides strong evidence for a critical role for the KV7.2- and KV7.3-containing channels in DSM function at both cellular and tissue levels.
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Affiliation(s)
- Aaron Provence
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina
| | - John Malysz
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina
| | - Georgi V Petkov
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina
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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] [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.
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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.
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Steady-state modulation of voltage-gated K+ channels in rat arterial smooth muscle by cyclic AMP-dependent protein kinase and protein phosphatase 2B. PLoS One 2015; 10:e0121285. [PMID: 25793374 PMCID: PMC4368632 DOI: 10.1371/journal.pone.0121285] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 01/29/2015] [Indexed: 01/17/2023] Open
Abstract
Voltage-gated potassium channels (Kv) are important regulators of membrane potential in vascular smooth muscle cells, which is integral to controlling intracellular Ca2+ concentration and regulating vascular tone. Previous work indicates that Kv channels can be modulated by receptor-driven alterations of cyclic AMP-dependent protein kinase (PKA) activity. Here, we demonstrate that Kv channel activity is maintained by tonic activity of PKA. Whole-cell recording was used to assess the effect of manipulating PKA signalling on Kv and ATP-dependent K+ channels of rat mesenteric artery smooth muscle cells. Application of PKA inhibitors, KT5720 or H89, caused a significant inhibition of Kv currents. Tonic PKA-mediated activation of Kv appears maximal as application of isoprenaline (a β-adrenoceptor agonist) or dibutyryl-cAMP failed to enhance Kv currents. We also show that this modulation of Kv by PKA can be reversed by protein phosphatase 2B/calcineurin (PP2B). PKA-dependent inhibition of Kv by KT5720 can be abrogated by pre-treatment with the PP2B inhibitor cyclosporin A, or inclusion of a PP2B auto-inhibitory peptide in the pipette solution. Finally, we demonstrate that tonic PKA-mediated modulation of Kv requires intact caveolae. Pre-treatment of the cells with methyl-β-cyclodextrin to deplete cellular cholesterol, or adding caveolin-scaffolding domain peptide to the pipette solution to disrupt caveolae-dependent signalling each attenuated PKA-mediated modulation of the Kv current. These findings highlight a novel, caveolae-dependent, tonic modulatory role of PKA on Kv channels providing new insight into mechanisms and the potential for pharmacological manipulation of vascular tone.
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Stott JB, Barrese V, Jepps TA, Leighton EV, Greenwood IA. Contribution of Kv7 channels to natriuretic peptide mediated vasodilation in normal and hypertensive rats. Hypertension 2014; 65:676-82. [PMID: 25547342 DOI: 10.1161/hypertensionaha.114.04373] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The Kv7 family of voltage-gated potassium channels are expressed within the vasculature where they are key regulators of vascular tone and mediate cAMP-linked endogenous vasodilator responses, a pathway that is compromised in hypertension. However, the role of Kv7 channels in non-cAMP-linked vasodilator pathways has not been investigated. Natriuretic peptides are potent vasodilators, which operate primarily through the activation of a cGMP-dependent signaling pathway. This study investigated the putative role of Kv7 channels in natriuretic peptide-dependent relaxations in the vasculature of normal and hypertensive animals. Relaxant responses of rat aorta to both atrial and C-type natriuretic peptides and the nitric oxide donor sodium nitroprusside were impaired by the Kv7 blocker linopirdine (10 μmol/L) but not by the Kv7.1-specific blocker HMR1556 (10 μmol/L) and other K(+) channel blockers. In contrast, only the atrial natriuretic peptide response was sensitive to linopirdine in the renal artery. These Kv7-mediated responses were attenuated in arteries from hypertensive rats. Quantitative polymerase chain reaction showed that A- and B-type natriuretic peptide receptors were expressed at high levels in the aorta and renal artery from normal and spontaneously hypertensive rats. This study provides the first evidence that natriuretic peptide responses are impaired in hypertension and that recruitment of Kv7 channels is a key component of natriuretic peptide-dependent vasodilations.
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Affiliation(s)
- Jennifer B Stott
- From the Vascular Biology Research Centre, Institute for Cardiovascular and Cell Sciences, St George's University of London, London, United Kingdom (J.B.S., V.B., E.V.L., I.A.G.); and Ion Channels Group, Institute of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark (T.A.J.)
| | - Vincenzo Barrese
- From the Vascular Biology Research Centre, Institute for Cardiovascular and Cell Sciences, St George's University of London, London, United Kingdom (J.B.S., V.B., E.V.L., I.A.G.); and Ion Channels Group, Institute of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark (T.A.J.)
| | - Thomas A Jepps
- From the Vascular Biology Research Centre, Institute for Cardiovascular and Cell Sciences, St George's University of London, London, United Kingdom (J.B.S., V.B., E.V.L., I.A.G.); and Ion Channels Group, Institute of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark (T.A.J.)
| | - Emma V Leighton
- From the Vascular Biology Research Centre, Institute for Cardiovascular and Cell Sciences, St George's University of London, London, United Kingdom (J.B.S., V.B., E.V.L., I.A.G.); and Ion Channels Group, Institute of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark (T.A.J.)
| | - Iain A Greenwood
- From the Vascular Biology Research Centre, Institute for Cardiovascular and Cell Sciences, St George's University of London, London, United Kingdom (J.B.S., V.B., E.V.L., I.A.G.); and Ion Channels Group, Institute of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark (T.A.J.).
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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] [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.
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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:
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Oliveras A, Roura-Ferrer M, Solé L, de la Cruz A, Prieto A, Etxebarria A, Manils J, Morales-Cano D, Condom E, Soler C, Cogolludo A, Valenzuela C, Villarroel A, Comes N, Felipe A. Functional assembly of Kv7.1/Kv7.5 channels with emerging properties on vascular muscle physiology. Arterioscler Thromb Vasc Biol 2014; 34:1522-30. [PMID: 24855057 DOI: 10.1161/atvbaha.114.303801] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Voltage-dependent K(+) (Kv) channels from the Kv7 family are expressed in blood vessels and contribute to cardiovascular physiology. Although Kv7 channel blockers trigger muscle contractions, Kv7 activators act as vasorelaxants. Kv7.1 and Kv7.5 are expressed in many vessels. Kv7.1 is under intense investigation because Kv7.1 blockers fail to modulate smooth muscle reactivity. In this study, we analyzed whether Kv7.1 and Kv7.5 may form functional heterotetrameric channels increasing the channel diversity in vascular smooth muscles. APPROACH AND RESULTS Kv7.1 and Kv7.5 currents elicited in arterial myocytes, oocyte, and mammalian expression systems suggest the formation of heterotetrameric complexes. Kv7.1/Kv7.5 heteromers, exhibiting different pharmacological characteristics, participate in the arterial tone. Kv7.1/Kv7.5 associations were confirmed by coimmunoprecipitation, fluorescence resonance energy transfer, and fluorescence recovery after photobleaching experiments. Kv7.1/Kv7.5 heterotetramers were highly retained at the endoplasmic reticulum. Studies in HEK-293 cells, heart, brain, and smooth and skeletal muscles demonstrated that the predominant presence of Kv7.5 stimulates release of Kv7.1/Kv7.5 oligomers out of lipid raft microdomains. Electrophysiological studies supported that KCNE1 and KCNE3 regulatory subunits further increased the channel diversity. Finally, the analysis of rat isolated myocytes and human blood vessels demonstrated that Kv7.1 and Kv7.5 exhibited a differential expression, which may lead to channel diversity. CONCLUSIONS Kv7.1 and Kv7.5 form heterotetrameric channels increasing the diversity of structures which fine-tune blood vessel reactivity. Because the lipid raft localization of ion channels is crucial for cardiovascular physiology, Kv7.1/Kv7.5 heteromers provide efficient spatial and temporal regulation of smooth muscle function. Our results shed light on the debate about the contribution of Kv7 channels to vasoconstriction and hypertension.
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Affiliation(s)
- Anna Oliveras
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Meritxell Roura-Ferrer
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Laura Solé
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Alicia de la Cruz
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Angela Prieto
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Ainhoa Etxebarria
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Joan Manils
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Daniel Morales-Cano
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Enric Condom
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Concepció Soler
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Angel Cogolludo
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Carmen Valenzuela
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Alvaro Villarroel
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Núria Comes
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.)
| | - Antonio Felipe
- From the Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain (A.O., M.R.-F., L.S., N.C., A.F.); Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, País Vasco, Spain (M.R.-F., A.E., A.V.); Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-Universidad Autónoma de Madrid, Madrid, Spain (A.d.l.C., A.P., C.V.); Departament de Patologia i Terapèutica Experimental, Hospital Universitari de Bellvitge-Universitat de Barcelona, Barcelona, Spain (J.M., E.C., C.S.); and Departamento de Farmacología, Universidad Complutense de Madrid, Ciber Enfermedades Respiratorias (CibeRes), Madrid, Spain (A.C., D.M.-C.).
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Currò D. K+ channels as potential targets for the treatment of gastrointestinal motor disorders. Eur J Pharmacol 2014; 733:97-101. [PMID: 24726846 DOI: 10.1016/j.ejphar.2014.03.049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/14/2014] [Accepted: 03/27/2014] [Indexed: 12/21/2022]
Abstract
K(+) channels play important functional roles in excitable cells, as neurons and muscle cells. The activation or inhibition of K(+) channels hyperpolarizes or depolarizes the cell membrane, respectively. These effects determine in the smooth muscle decrease or increase in Ca(2+) influx through voltage-gated Ca(2+) (CaV1.2) channels and relaxation or contraction, respectively. Recent studies highlight the importance of voltage-dependent type 7 K(+) (KV7 or KCNQ) channels in regulating muscle tone and contractility in stomach and colon. KV7 channels, that include 5 subtypes (KV7.1-7.5), are activated at relatively negative potential values, close to those of the resting membrane potential for the smooth muscle cells of some segments of the gastrointestinal tract. Thus, they contribute to set the resting membrane potential and their blockade induces increase in smooth muscle contractility in stomach and colon. In addition, KV7 channel activation produces profound relaxations of gastric and colonic smooth muscle. Therefore, KV7 channel activators could be used to relax the smooth muscle and relieve symptoms in diseases such as functional dyspepsia and irritable bowel syndrome with prevalent diarrhea. The discovery of activators selective for the channel subtypes present in the smooth muscle, mainly KV7.4 and 7.5, would allow avoiding adverse cardiac and nervous system effects. A further step forward would be characterizing putative differences among the KV7 channel subtypes expressed in the various smooth muscles and synthesizing molecules specific for the gastrointestinal smooth muscle.
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Affiliation(s)
- Diego Currò
- Institute of Pharmacology, School of Medicine, Catholic University of the Sacred Heart, L.go F. Vito 1, 00168 Rome, Italy.
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49
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Stott JB, Jepps TA, Greenwood IA. KV7 potassium channels: a new therapeutic target in smooth muscle disorders. Drug Discov Today 2014; 19:413-24. [DOI: 10.1016/j.drudis.2013.12.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/21/2013] [Accepted: 12/04/2013] [Indexed: 12/23/2022]
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Chadha PS, Jepps TA, Carr G, Stott JB, Zhu HL, Cole WC, Greenwood IA. Contribution of kv7.4/kv7.5 heteromers to intrinsic and calcitonin gene-related peptide-induced cerebral reactivity. Arterioscler Thromb Vasc Biol 2014; 34:887-93. [PMID: 24558103 DOI: 10.1161/atvbaha.114.303405] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Middle cerebral artery (MCA) diameter is regulated by inherent myogenic activity and the effect of potent vasodilators such as calcitonin gene-related peptide (CGRP). Previous studies showed that MCAs express KCNQ1, 4, and 5 potassium channel genes, and the expression products (Kv7 channels) participate in the myogenic control of MCA diameter. The present study investigated the contribution of Kv7.4 and Kv7.5 isoforms to myogenic and CGRP regulation of MCA diameter and determined whether they were affected in hypertensive animals. APPROACH AND RESULTS Isometric tension recordings performed on MCA from normotensive rats produced CGRP vasodilations that were inhibited by the pan-Kv7 channel blocker linopirdine (P<0.01) and after transfection of arteries with siRNA against KCNQ4 (P<0.01) but not KCNQ5. However, isobaric myography revealed that myogenic constriction in response to increases in intravascular pressure (20-80 mm Hg) was affected by both KCNQ4 and KCNQ5 siRNA. Proximity ligation assay signals were equally abundant for Kv7.4/Kv7.4 or Kv7.4/Kv7.5 antibody combinations but minimal for Kv7.5/Kv7.5 antibodies or Kv7.4/7.1 combinations. In contrast to systemic arteries, Kv7 function and Kv7.4 abundance in MCA were not altered in hypertensive rats. CONCLUSIONS This study reveals, for the first time to our knowledge, that in cerebral arteries, Kv7.4 and Kv7.5 proteins exist predominantly as a functional heterotetramer, which regulates intrinsic myogenicity and vasodilation attributed to CGRP. Surprisingly, unlike systemic arteries, Kv7 activity in MCAs is not affected by the development of hypertension, and CGRP-mediated vasodilation is well maintained. As such, cerebrovascular Kv7 channels could be amenable for therapeutic targeting in conditions such as cerebral vasospasm.
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Affiliation(s)
- Preet S Chadha
- From the Division of Biomedical Sciences, Pharmacology and Cell Physiology Research Group, St George's University of London, London, United Kingdom (P.S.C., T.A.J., G.C., J.B.S., I.A.G.); and The Smooth Muscle Research Group, Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada (H.-L.Z., W.C.C.)
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