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Jiao D, Xu L, Gu Z, Yan H, Shen D, Gu X. Pathogenesis, diagnosis, and treatment of epilepsy: electromagnetic stimulation-mediated neuromodulation therapy and new technologies. Neural Regen Res 2025; 20:917-935. [PMID: 38989927 PMCID: PMC11438347 DOI: 10.4103/nrr.nrr-d-23-01444] [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: 08/28/2023] [Revised: 10/31/2023] [Accepted: 01/18/2024] [Indexed: 07/12/2024] Open
Abstract
Epilepsy is a severe, relapsing, and multifactorial neurological disorder. Studies regarding the accurate diagnosis, prognosis, and in-depth pathogenesis are crucial for the precise and effective treatment of epilepsy. The pathogenesis of epilepsy is complex and involves alterations in variables such as gene expression, protein expression, ion channel activity, energy metabolites, and gut microbiota composition. Satisfactory results are lacking for conventional treatments for epilepsy. Surgical resection of lesions, drug therapy, and non-drug interventions are mainly used in clinical practice to treat pain associated with epilepsy. Non-pharmacological treatments, such as a ketogenic diet, gene therapy for nerve regeneration, and neural regulation, are currently areas of research focus. This review provides a comprehensive overview of the pathogenesis, diagnostic methods, and treatments of epilepsy. It also elaborates on the theoretical basis, treatment modes, and effects of invasive nerve stimulation in neurotherapy, including percutaneous vagus nerve stimulation, deep brain electrical stimulation, repetitive nerve electrical stimulation, in addition to non-invasive transcranial magnetic stimulation and transcranial direct current stimulation. Numerous studies have shown that electromagnetic stimulation-mediated neuromodulation therapy can markedly improve neurological function and reduce the frequency of epileptic seizures. Additionally, many new technologies for the diagnosis and treatment of epilepsy are being explored. However, current research is mainly focused on analyzing patients' clinical manifestations and exploring relevant diagnostic and treatment methods to study the pathogenesis at a molecular level, which has led to a lack of consensus regarding the mechanisms related to the disease.
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Affiliation(s)
- Dian Jiao
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
| | - Lai Xu
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
| | - Zhen Gu
- Key Laboratory of Advanced Drug Delivery Systems of Zhejiang Province, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Hua Yan
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
| | - Dingding Shen
- Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, China
| | - Xiaosong Gu
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
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2
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Wei S, Shiwen W, Cao‐wenjing C, Huajun Y, Qun W. A randomized, double-blind, placebo-controlled, dose-escalating phase IIa trial to evaluate the safety, tolerability, efficacy, and pharmacokinetics of multiple oral doses of Pynegabine tablets as add-on therapy in patients with focal epilepsy. CNS Neurosci Ther 2024; 30:e70002. [PMID: 39252462 PMCID: PMC11386250 DOI: 10.1111/cns.70002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 07/29/2024] [Accepted: 08/06/2024] [Indexed: 09/11/2024] Open
Abstract
AIMS This study aims to investigate the safety, tolerability, efficacy, and pharmacokinetics of Pynegabine as an add-on therapy in the treatment of focal epilepsy. METHODOLOGY This is a protocol phase-IIa, randomized, double-blinded, placebo-controlled, multicenter study in patients with focal epilepsy from multiple centers in China who have been treated with at least 2 ASMs without effective control. The study involves an 8-week run-in period with stable use of previous medications. Patients are then randomized to receive either Pynegabine or a placebo. Sentinel administration is performed initially, and subsequent patients are randomized based on safety assessments. Three dose cohorts (15, 20, and 25 mg/d) are established. Efficacy is assessed through various measures, including seizure frequency, CGI score, PGI score, HAMA score, HAMD score, MoCA scale score, QOLIE-31 scale score, and 12 h-EEG score. Safety evaluations, PK blood samples, concomitant medications, and adverse events are also recorded. CONCLUSION Data from the study will be used to evaluate the safety, tolerability, efficacy, and pharmacokinetics of Pynegabine tablets as add-on therapy for focal epilepsy.
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Affiliation(s)
- Shan Wei
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
- Beijing Institute for Brain DisordersBeijingChina
| | - Weng Shiwen
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
- Beijing Institute for Brain DisordersBeijingChina
| | - Chang Cao‐wenjing
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
| | - Yang Huajun
- China National Clinical Research Center for Neurological DiseasesBeijingChina
- Beijing Institute for Brain DisordersBeijingChina
- Sanbo Brain HospitalCapital Medical UniversityBeijingChina
| | - Wang Qun
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
- Beijing Institute for Brain DisordersBeijingChina
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3
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Zhuang D, Yu N, Han S, Zhang X, Ju C. The Kv7 channel opener Retigabine reduces neuropathology and alleviates behavioral deficits in APP/PS1 transgenic mice. Behav Brain Res 2024; 471:115137. [PMID: 38971432 DOI: 10.1016/j.bbr.2024.115137] [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: 03/22/2024] [Revised: 06/19/2024] [Accepted: 07/01/2024] [Indexed: 07/08/2024]
Abstract
Hyperexcitability of neuronal networks is central to the pathogenesis of Alzheimer's disease (AD). Pharmacological activation of Kv7 channels is an effective way to reduce neuronal firing. Our results showed that that pharmacologically activating the Kv7 channel with Retigabine (RTG) can alleviate cognitive impairment in mice without affecting spontaneous activity. RTG could also ameliorate damage to the Nissl bodies in cortex and hippocampal CA and DG regions in 9-month-old APP/PS1 mice. Additionally, RTG could reduce the Aβ plaque number in the hippocampus and cortex of both 6-month-old and 9-month-old mice. By recordings of electroencephalogram, we showed that a decrease in the number of abnormal discharges in the brains of the AD model mice when the Kv7 channel was opened. Moreover, Western blot analysis revealed a reduction in the expression of the p-Tau protein in both the hippocampus and cortex upon Kv7 channel opening. These findings suggest that Kv7 channel opener RTG may ameliorate cognitive impairment in AD, most likely by reducing brain excitability.
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Affiliation(s)
- Dongpei Zhuang
- Department of Pharmacology, School of Pharmacy, Qingdao University Qingdao Medical College, China.
| | - Nan Yu
- Department of Pharmacy, Qingdao Eighth People's Hospital, China.
| | - Shuo Han
- Department of Pharmacology, School of Pharmacy, Qingdao University Qingdao Medical College, China.
| | - Xinyao Zhang
- Department of Pharmacology, School of Pharmacy, Qingdao University Qingdao Medical College, China.
| | - Chuanxia Ju
- Department of Pharmacology, School of Pharmacy, Qingdao University Qingdao Medical College, China.
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4
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Lai H, Gao M, Yang H. The potassium channels: Neurobiology and pharmacology of tinnitus. J Neurosci Res 2024; 102:e25281. [PMID: 38284861 DOI: 10.1002/jnr.25281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 10/27/2023] [Accepted: 11/16/2023] [Indexed: 01/30/2024]
Abstract
Tinnitus is a widespread public health issue that imposes a significant social burden. The occurrence and maintenance of tinnitus have been shown to be associated with abnormal neuronal activity in the auditory pathway. Based on this view, neurobiological and pharmacological developments in tinnitus focus on ion channels and synaptic neurotransmitter receptors in neurons in the auditory pathway. With major breakthroughs in the pathophysiology and research methodology of tinnitus in recent years, the role of the largest family of ion channels, potassium ion channels, in modulating the excitability of neurons involved in tinnitus has been increasingly demonstrated. More and more potassium channels involved in the neural mechanism of tinnitus have been discovered, and corresponding drugs have been developed. In this article, we review animal (mouse, rat, hamster, and guinea-pig), human, and genetic studies on the different potassium channels involved in tinnitus, analyze the limitations of current clinical research on potassium channels, and propose future prospects. The aim of this review is to promote the understanding of the role of potassium ion channels in tinnitus and to advance the development of drugs targeting potassium ion channels for tinnitus.
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Affiliation(s)
- Haohong Lai
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Minqian Gao
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Hearing and Speech-Language Science, Guangzhou Xinhua University, Guangzhou, China
| | - Haidi Yang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Hearing and Speech-Language Science, Guangzhou Xinhua University, Guangzhou, China
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5
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Ying Y, Gong L, Tao X, Ding J, Chen N, Yao Y, Liu J, Chen C, Zhu T, Jiang P. Genetic Knockout of TRPM2 Increases Neuronal Excitability of Hippocampal Neurons by Inhibiting Kv7 Channel in Epilepsy. Mol Neurobiol 2022; 59:6918-6933. [PMID: 36053438 DOI: 10.1007/s12035-022-02993-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/07/2022] [Indexed: 11/30/2022]
Abstract
Epilepsy is a chronic brain disease that makes serious cognitive and motor retardation. Ion channels affect the occurrence of epilepsy in various ways, but the mechanisms have not yet been fully elucidated. Transient receptor potential melastain2 (TRPM2) ion channel is a non-selective cationic channel that can permeate Ca2+ and critical for epilepsy. Here, TRPM2 gene knockout mice were used to generate a chronic kindling epilepsy model by PTZ administration in mice. We found that TRPM2 knockout mice were more susceptible to epilepsy than WT mice. Furthermore, the neuronal excitability in the hippocampal CA1 region of TRPM2 knockout mice was significantly increased. Compared with WT group, there were no significant differences in the input resistance and after hyperpolarization of CA1 neurons in TRPM2 knockout mice. Firing adaptation rate of hippocampal CA1 pyramidal neurons of TRPM2 knockout mice was lower than that of WT mice. We also found that activation of Kv7 channel by retigabine reduced the firing frequency of action potential in the hippocampal pyramidal neurons of TRPM2 knockout mice. However, inhibiting Kv7 channel increased the firing frequency of action potential in hippocampal pyramidal neurons of WT mice. The data suggest that activation of Kv7 channel can effectively reduce epileptic seizures in TRPM2 knockout mice. We conclude that genetic knockout of TRPM2 in hippocampal CA1 pyramidal neurons may increase neuronal excitability by inhibiting Kv7 channel, affecting the susceptibility to epilepsy. These findings may provide a potential therapeutic target for epilepsy.
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Affiliation(s)
- Yingchao Ying
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Lifen Gong
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Xiaohan Tao
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Junchao Ding
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
- Department of Pediatrics, Yiwu Maternal and Child Health Care Hospital, Yiwu, China
| | - Nannan Chen
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Yinping Yao
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
- Department of Pediatrics, Shaoxing People's Hospital, Shaoxing, China
| | - Jiajing Liu
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Chen Chen
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Tao Zhu
- Department of Critical Care Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Peifang Jiang
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China.
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6
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Liu LX, Gu RR, Jin Y, Chen XQ, Li XW, Zheng YM, Gao ZB, Guo YW. Diversity-oriented synthesis of marine polybrominated diphenyl ethers as potential KCNQ potassium channel activators. Bioorg Chem 2022; 126:105909. [DOI: 10.1016/j.bioorg.2022.105909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/03/2022] [Accepted: 05/22/2022] [Indexed: 01/10/2023]
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7
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Lou S, Cui S. Drug treatment of epilepsy: From serendipitous discovery to evolutionary mechanisms. Curr Med Chem 2021; 29:3366-3391. [PMID: 34514980 DOI: 10.2174/0929867328666210910124727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/17/2021] [Accepted: 07/21/2021] [Indexed: 11/22/2022]
Abstract
Epilepsy is a chronic brain disorder caused by abnormal firing of neurons. Up to now, using antiepileptic drugs is the main method of epilepsy treatment. The development of antiepileptic drugs lasted for centuries. In general, most agents entering clinical practice act on the balance mechanisms of brain "excitability-inhibition". More specifically, they target voltage-gated ion channels, GABAergic transmission and glutamatergic transmission. In recent years, some novel drugs representing new mechanisms of action have been discovered. Although there are about 30 available drugs in the market, it is still in urgent need of discovering more effective and safer drugs. The development of new antiepileptic drugs is into a new era: from serendipitous discovery to evolutionary mechanism-based design. This article presents an overview of drug treatment of epilepsy, including a series of traditional and novel drugs.
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Affiliation(s)
- Shengying Lou
- Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou. China
| | - Sunliang Cui
- Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou. China
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8
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Abstract
Kv7.1-Kv7.5 (KCNQ1-5) K+ channels are voltage-gated K+ channels with major roles in neurons, muscle cells and epithelia where they underlie physiologically important K+ currents, such as neuronal M current and cardiac IKs. Specific biophysical properties of Kv7 channels make them particularly well placed to control the activity of excitable cells. Indeed, these channels often work as 'excitability breaks' and are targeted by various hormones and modulators to regulate cellular activity outputs. Genetic deficiencies in all five KCNQ genes result in human excitability disorders, including epilepsy, arrhythmias, deafness and some others. Not surprisingly, this channel family attracts considerable attention as potential drug targets. Here we will review biophysical properties and tissue expression profile of Kv7 channels, discuss recent advances in the understanding of their structure as well as their role in various neurological, cardiovascular and other diseases and pathologies. We will also consider a scope for therapeutic targeting of Kv7 channels for treatment of the above health conditions.
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9
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Levchenko A, Vyalova NM, Nurgaliev T, Pozhidaev IV, Simutkin GG, Bokhan NA, Ivanova SA. NRG1, PIP4K2A, and HTR2C as Potential Candidate Biomarker Genes for Several Clinical Subphenotypes of Depression and Bipolar Disorder. Front Genet 2020; 11:936. [PMID: 33193575 PMCID: PMC7478333 DOI: 10.3389/fgene.2020.00936] [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: 11/12/2019] [Accepted: 07/27/2020] [Indexed: 12/20/2022] Open
Abstract
GSK3B, BDNF, NGF, NRG1, HTR2C, and PIP4K2A play important roles in molecular mechanisms of psychiatric disorders. GSK3B occupies a central position in these molecular mechanisms and is also modulated by psychotropic drugs. BDNF regulates a number of key aspects in neurodevelopment and synaptic plasticity. NGF exerts a trophic action and is implicated in cerebral alterations associated with psychiatric disorders. NRG1 is active in neural development, synaptic plasticity, and neurotransmission. HTR2C is another important psychopharmacological target. PIP4K2A catalyzes the phosphorylation of PI5P to form PIP2, the latter being implicated in various aspects of neuronal signal transduction. In the present study, the six genes were sequenced in a cohort of 19 patients with bipolar affective disorder, 41 patients with recurrent depressive disorder, and 55 patients with depressive episode. The study revealed a number of genetic variants associated with antidepressant treatment response, time to recurrence of episodes, and depression severity. Namely, alleles of rs35641374 and rs10508649 (NRG1 and PIP4K2A) may be prognostic biomarkers of time to recurrence of depressive and manic/mixed episodes among patients with bipolar affective disorder. Alleles of NC_000008.11:g.32614509_32614510del, rs61731109, and rs10508649 (also NRG1 and PIP4K2A) seem to be predictive biomarkers of response to pharmacological antidepressant treatment on the 28th day assessed by the HDRS-17 or CGI-I scale. In particular, the allele G of rs10508649 (PIP4K2A) may increase resistance to antidepressant treatment and be at the same time protective against recurrent manic/mixed episodes. These results support previous data indicating a biological link between resistance to antidepressant treatment and mania. Bioinformatic functional annotation of associated variants revealed possible impact for transcriptional regulation of PIP4K2A. In addition, the allele A of rs2248440 (HTR2C) may be a prognostic biomarker of depression severity. This allele decreases expression of the neighboring immune system gene IL13RA2 in the putamen according to the GTEx portal. The variant rs2248440 is near rs6318 (previously associated with depression and effects of psychotropic drugs) that is an eQTL for the same gene and tissue. Finally, the study points to several protein interactions relevant in the pathogenesis of mood disorders. Functional studies using cellular or animal models are warranted to support these results.
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Affiliation(s)
- Anastasia Levchenko
- Theodosius Dobzhansky Center for Genome Bioinformatics, Saint Petersburg State University, Saint Petersburg, Russia
| | - Natalia M Vyalova
- Tomsk National Research Medical Center, Mental Health Research Institute, Russian Academy of Sciences, Tomsk, Russia
| | - Timur Nurgaliev
- Institute of Translational Biomedicine, Saint Petersburg State University, Saint Petersburg, Russia
| | - Ivan V Pozhidaev
- Tomsk National Research Medical Center, Mental Health Research Institute, Russian Academy of Sciences, Tomsk, Russia
| | - German G Simutkin
- Tomsk National Research Medical Center, Mental Health Research Institute, Russian Academy of Sciences, Tomsk, Russia
| | - Nikolay A Bokhan
- Tomsk National Research Medical Center, Mental Health Research Institute, Russian Academy of Sciences, Tomsk, Russia.,National Research Tomsk State University, Tomsk, Russia.,Siberian State Medical University, Tomsk, Russia
| | - Svetlana A Ivanova
- Tomsk National Research Medical Center, Mental Health Research Institute, Russian Academy of Sciences, Tomsk, Russia.,Siberian State Medical University, Tomsk, Russia.,National Research Tomsk Polytechnic University, Tomsk, Russia
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10
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Vigil FA, Carver CM, Shapiro MS. Pharmacological Manipulation of K v 7 Channels as a New Therapeutic Tool for Multiple Brain Disorders. Front Physiol 2020; 11:688. [PMID: 32636759 PMCID: PMC7317068 DOI: 10.3389/fphys.2020.00688] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 05/27/2020] [Indexed: 12/12/2022] Open
Abstract
K v 7 ("M-type," KCNQ) K+ currents, play dominant roles in controlling neuronal excitability. They act as a "brake" against hyperexcitable states in the central and peripheral nervous systems. Pharmacological augmentation of M current has been developed for controlling epileptic seizures, although current pharmacological tools are uneven in practical usefulness. Lately, however, M-current "opener" compounds have been suggested to be efficacious in preventing brain damage after multiple types of insults/diseases, such as stroke, traumatic brain injury, drug addiction and mood disorders. In this review, we will discuss what is known to date on these efforts and identify gaps in our knowledge regarding the link between M current and therapeutic potential for these disorders. We will outline the preclinical experiments that are yet to be performed to demonstrate the likelihood of success of this approach in human trials. Finally, we also address multiple pharmacological tools available to manipulate different K v 7 subunits and the relevant evidence for translational application in the clinical use for disorders of the central nervous system and multiple types of brain insults. We feel there to be great potential for manipulation of K v 7 channels as a novel therapeutic mode of intervention in the clinic, and that the paucity of existing therapies obligates us to perform further research, so that patients can soon benefit from such therapeutic approaches.
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Affiliation(s)
- Fabio A Vigil
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Chase M Carver
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Mark S Shapiro
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
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11
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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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12
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Barro-Soria R, Liin SI, Larsson HP. Specificity of M-channel activators: binding or effect? J Physiol 2018; 595:605-606. [PMID: 28145011 DOI: 10.1113/jp273250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Rene Barro-Soria
- Department of Physiology and Biophysics, University of Miami, Miami, FL, 33136, USA
| | - Sara I Liin
- Department of Clinical and Experimental Medicine, Linköping University, SE-581, 85, Linköping, Sweden
| | - H Peter Larsson
- Department of Physiology and Biophysics, University of Miami, Miami, FL, 33136, USA
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13
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Du X, Gao H, Jaffe D, Zhang H, Gamper N. M-type K + channels in peripheral nociceptive pathways. Br J Pharmacol 2018; 175:2158-2172. [PMID: 28800673 PMCID: PMC5980636 DOI: 10.1111/bph.13978] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/17/2017] [Accepted: 08/03/2017] [Indexed: 12/22/2022] Open
Abstract
Pathological pain is a hyperexcitability disorder. Since the excitability of a neuron is set and controlled by a complement of ion channels it expresses, in order to understand and treat pain, we need to develop a mechanistic insight into the key ion channels controlling excitability within the mammalian pain pathways and how these ion channels are regulated and modulated in various physiological and pathophysiological settings. In this review, we will discuss the emerging data on the expression in pain pathways, functional role and modulation of a family of voltage-gated K+ channels called 'M channels' (KCNQ, Kv 7). M channels are increasingly recognized as important players in controlling pain signalling, especially within the peripheral somatosensory system. We will also discuss the therapeutic potential of M channels as analgesic drug targets. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc/.
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Affiliation(s)
- Xiaona Du
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
| | - Haixia Gao
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeedsUK
| | - David Jaffe
- Department of Biology, UTSA Neurosciences InstituteUniversity of Texas at San AntonioSan AntonioTXUSA
| | - Hailin Zhang
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
| | - Nikita Gamper
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeedsUK
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14
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Yang S, Lu D, Ouyang P. Design, synthesis and evaluation of novel N-phenylbutanamide derivatives as KCNQ openers for the treatment of epilepsy. Bioorg Med Chem Lett 2018; 28:3004-3008. [PMID: 30061030 DOI: 10.1016/j.bmcl.2018.05.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 10/16/2022]
Abstract
KCNQ (Kv7) has emerged as a validated target for the development of novel anti-epileptic drugs. In this paper, a series of novel N-phenylbutanamide derivatives were designed, synthesized and evaluated as KCNQ openers for the treatment of epilepsy. These compounds were evaluated for their KCNQ opening activity in vitro and in vivo. Several compounds were found to be potent KCNQ openers. Compound 1 with favorable in vitro activity was submitted to evaluation in vivo. Results showed that compound 1 owned significant anti-convulsant activity with no adverse effects. It was also found to posses favorable pharmacokinetic profiles in rat. This research may provide novel potent compounds for the discovery of KCNQ openers in treating epilepsy.
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Affiliation(s)
- Shaoning Yang
- School of Pharmaceutical Sciences, Nanjing University of Technology, Nanjing 211816, PR China; Jiangsu Simcere Pharmaceutical Co. Ltd., Nanjing 210042, PR China
| | - Dingqiang Lu
- School of Pharmaceutical Sciences, Nanjing University of Technology, Nanjing 211816, PR China.
| | - Pingkai Ouyang
- School of Pharmaceutical Sciences, Nanjing University of Technology, Nanjing 211816, PR China
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15
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Bruce HA, Kochunov P, Paciga SA, Hyde CL, Chen X, Xie Z, Zhang B, Xi HS, O'Donnell P, Whelan C, Schubert CR, Bellon A, Ament SA, Shukla DK, Du X, Rowland LM, O'Neill H, Hong LE. Potassium channel gene associations with joint processing speed and white matter impairments in schizophrenia. GENES BRAIN AND BEHAVIOR 2017; 16:515-521. [PMID: 28188958 DOI: 10.1111/gbb.12372] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 01/14/2017] [Accepted: 02/07/2017] [Indexed: 12/17/2022]
Abstract
Patients with schizophrenia show decreased processing speed on neuropsychological testing and decreased white matter integrity as measured by diffusion tensor imaging, two traits shown to be both heritable and genetically associated indicating that there may be genes that influence both traits as well as schizophrenia disease risk. The potassium channel gene family is a reasonable candidate to harbor such a gene given the prominent role potassium channels play in the central nervous system in signal transduction, particularly in myelinated axons. We genotyped members of the large potassium channel gene family focusing on putatively functional single nucleotide polymorphisms (SNPs) in a population of 363 controls, 194 patients with schizophrenia spectrum disorder (SSD) and 28 patients with affective disorders with psychotic features who completed imaging and neuropsychological testing. We then performed three association analyses using three phenotypes - processing speed, whole-brain white matter fractional anisotropy (FA) and schizophrenia spectrum diagnosis. We extracted SNPs showing an association at a nominal P value of <0.05 with all three phenotypes in the expected direction: decreased processing speed, decreased FA and increased risk of SSD. A single SNP, rs8234, in the 3' untranslated region of voltage-gated potassium channel subfamily Q member 1 (KCNQ1) was identified. Rs8234 has been shown to affect KCNQ1 expression levels, and KCNQ1 levels have been shown to affect neuronal action potentials. This exploratory analysis provides preliminary data suggesting that KCNQ1 may contribute to the shared risk for diminished processing speed, diminished white mater integrity and increased risk of schizophrenia.
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Affiliation(s)
- H A Bruce
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - P Kochunov
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - S A Paciga
- Pfizer Inc., Worldwide Research and Development, Cambridge, MA
| | - C L Hyde
- Pfizer Inc., Worldwide Research and Development, Cambridge, MA
| | - X Chen
- Pfizer Inc., Worldwide Research and Development, Cambridge, MA
| | - Z Xie
- Pfizer Inc., Worldwide Research and Development, Cambridge, MA
| | - B Zhang
- Pfizer Inc., Worldwide Research and Development, Cambridge, MA
| | - H S Xi
- Pfizer Inc., Worldwide Research and Development, Cambridge, MA
| | - P O'Donnell
- Pfizer Inc., Worldwide Research and Development, Cambridge, MA
| | - C Whelan
- Pfizer Inc., Worldwide Research and Development, Cambridge, MA
| | | | - A Bellon
- Department of Psychiatry, Penn State Hershey Medical Center, Hershey, PA, USA
| | - S A Ament
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - D K Shukla
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - X Du
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - L M Rowland
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - H O'Neill
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - L E Hong
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
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16
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Hansen HH, Weikop P, Mikkelsen MD, Rode F, Mikkelsen JD. The pan-Kv7 (KCNQ) Channel Opener Retigabine Inhibits Striatal Excitability by Direct Action on Striatal Neurons In Vivo. Basic Clin Pharmacol Toxicol 2016; 120:46-51. [PMID: 27377794 DOI: 10.1111/bcpt.12636] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/30/2016] [Indexed: 11/29/2022]
Abstract
Central Kv7 (KCNQ) channels are voltage-dependent potassium channels composed of different combinations of four Kv7 subunits, being differently expressed in the brain. Notably, striatal dopaminergic neurotransmission is strongly suppressed by systemic administration of the pan-Kv7 channel opener retigabine. The effect of retigabine likely involves the inhibition of the activity in mesencephalic dopaminergic neurons projecting to the striatum, but whether Kv7 channels expressed in the striatum may also play a role is not resolved. We therefore assessed the effect of intrastriatal retigabine administration on striatal neuronal excitability in the rat determined by c-Fos immunoreactivity, a marker of neuronal activation. When retigabine was applied locally in the striatum, this resulted in a marked reduction in the number of c-Fos-positive neurons after a strong excitatory striatal stimulus induced by acute systemic haloperidol administration in the rat. The relative mRNA levels of Kv7 subunits in the rat striatum were found to be Kv7.2 = Kv7.3 = Kv7.5 > >Kv7.4. These data suggest that intrastriatal Kv7 channels play a direct role in regulating striatal excitability in vivo.
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Affiliation(s)
- Henrik H Hansen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Denmark.,NeuroSearch A/S, Ballerup, Denmark
| | - Pia Weikop
- Neuropsychiatric Laboratory, Copenhagen University Hospital, Rigshospitalet, Denmark
| | | | | | - Jens D Mikkelsen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Denmark.,NeuroSearch A/S, Ballerup, Denmark
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17
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Imbrici P, Liantonio A, Camerino GM, De Bellis M, Camerino C, Mele A, Giustino A, Pierno S, De Luca A, Tricarico D, Desaphy JF, Conte D. Therapeutic Approaches to Genetic Ion Channelopathies and Perspectives in Drug Discovery. Front Pharmacol 2016; 7:121. [PMID: 27242528 PMCID: PMC4861771 DOI: 10.3389/fphar.2016.00121] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 04/25/2016] [Indexed: 12/21/2022] Open
Abstract
In the human genome more than 400 genes encode ion channels, which are transmembrane proteins mediating ion fluxes across membranes. Being expressed in all cell types, they are involved in almost all physiological processes, including sense perception, neurotransmission, muscle contraction, secretion, immune response, cell proliferation, and differentiation. Due to the widespread tissue distribution of ion channels and their physiological functions, mutations in genes encoding ion channel subunits, or their interacting proteins, are responsible for inherited ion channelopathies. These diseases can range from common to very rare disorders and their severity can be mild, disabling, or life-threatening. In spite of this, ion channels are the primary target of only about 5% of the marketed drugs suggesting their potential in drug discovery. The current review summarizes the therapeutic management of the principal ion channelopathies of central and peripheral nervous system, heart, kidney, bone, skeletal muscle and pancreas, resulting from mutations in calcium, sodium, potassium, and chloride ion channels. For most channelopathies the therapy is mainly empirical and symptomatic, often limited by lack of efficacy and tolerability for a significant number of patients. Other channelopathies can exploit ion channel targeted drugs, such as marketed sodium channel blockers. Developing new and more specific therapeutic approaches is therefore required. To this aim, a major advancement in the pharmacotherapy of channelopathies has been the discovery that ion channel mutations lead to change in biophysics that can in turn specifically modify the sensitivity to drugs: this opens the way to a pharmacogenetics strategy, allowing the development of a personalized therapy with increased efficacy and reduced side effects. In addition, the identification of disease modifiers in ion channelopathies appears an alternative strategy to discover novel druggable targets.
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Affiliation(s)
- Paola Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Antonella Liantonio
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Giulia M Camerino
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Michela De Bellis
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Claudia Camerino
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro" Bari, Italy
| | - Antonietta Mele
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Arcangela Giustino
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro" Bari, Italy
| | - Sabata Pierno
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Annamaria De Luca
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Domenico Tricarico
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Jean-Francois Desaphy
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro" Bari, Italy
| | - Diana Conte
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
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18
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Rogawski MA, Löscher W, Rho JM. Mechanisms of Action of Antiseizure Drugs and the Ketogenic Diet. Cold Spring Harb Perspect Med 2016; 6:a022780. [PMID: 26801895 PMCID: PMC4852797 DOI: 10.1101/cshperspect.a022780] [Citation(s) in RCA: 176] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antiseizure drugs (ASDs), also termed antiepileptic drugs, are the main form of symptomatic treatment for people with epilepsy, but not all patients become free of seizures. The ketogenic diet is one treatment option for drug-resistant patients. Both types of therapy exert their clinical effects through interactions with one or more of a diverse set of molecular targets in the brain. ASDs act by modulation of voltage-gated ion channels, including sodium, calcium, and potassium channels; by enhancement of γ-aminobutyric acid (GABA)-mediated inhibition through effects on GABAA receptors, the GABA transporter 1 (GAT1) GABA uptake transporter, or GABA transaminase; through interactions with elements of the synaptic release machinery, including synaptic vesicle 2A (SV2A) and α2δ; or by blockade of ionotropic glutamate receptors, including α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptors. The ketogenic diet leads to increases in circulating ketones, which may contribute to the efficacy in treating pharmacoresistant seizures. Production in the brain of inhibitory mediators, such as adenosine, or ion channel modulators, such as polyunsaturated fatty acids, may also play a role. Metabolic effects, including diversion from glycolysis, are a further postulated mechanism. For some ASDs and the ketogenic diet, effects on multiple targets may contribute to activity. Better understanding of the ketogenic diet will inform the development of improved drug therapies to treat refractory seizures.
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Affiliation(s)
- Michael A Rogawski
- Department of Neurology, University of California, Davis, Sacramento, California 95817
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
| | - Jong M Rho
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada
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19
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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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20
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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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21
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KCNQ potassium channels in sensory system and neural circuits. Acta Pharmacol Sin 2016; 37:25-33. [PMID: 26687932 DOI: 10.1038/aps.2015.131] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/10/2015] [Indexed: 12/15/2022] Open
Abstract
M channels, an important regulator of neural excitability, are composed of four subunits of the Kv7 (KCNQ) K(+) channel family. M channels were named as such because their activity was suppressed by stimulation of muscarinic acetylcholine receptors. These channels are of particular interest because they are activated at the subthreshold membrane potentials. Furthermore, neural KCNQ channels are drug targets for the treatments of epilepsy and a variety of neurological disorders, including chronic and neuropathic pain, deafness, and mental illness. This review will update readers on the roles of KCNQ channels in the sensory system and neural circuits as well as discuss their respective mechanisms and the implications for physiology and medicine. We will also consider future perspectives and the development of additional pharmacological models, such as seizure, stroke, pain and mental illness, which work in combination with drug-design targeting of KCNQ channels. These models will hopefully deepen our understanding of KCNQ channels and provide general therapeutic prospects of related channelopathies.
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22
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Sucher NJ, Carles MC. A pharmacological basis of herbal medicines for epilepsy. Epilepsy Behav 2015; 52:308-18. [PMID: 26074183 DOI: 10.1016/j.yebeh.2015.05.012] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 05/06/2015] [Indexed: 01/25/2023]
Abstract
Epilepsy is the most common chronic neurological disease, affecting about 1% of the world's population during their lifetime. Most people with epilepsy can attain a seizure-free life upon treatment with antiepileptic drugs (AEDs). Unfortunately, seizures in up to 30% do not respond to treatment. It is estimated that 90% of people with epilepsy live in developing countries, and most of them receive no drug treatment for the disease. This treatment gap has motivated investigations into the effects of plants that have been used by traditional healers all over the world to treat seizures. Extracts of hundreds of plants have been shown to exhibit anticonvulsant activity in phenotypic screens performed in experimental animals. Some of those extracts appear to exhibit anticonvulsant efficacy similar to that of synthetic AEDs. Dozens of plant-derived chemical compounds have similarly been shown to act as anticonvulsants in various in vivo and in vitro assays. To a significant degree, anticonvulsant effects of plant extracts can be attributed to widely distributed flavonoids, (furano)coumarins, phenylpropanoids, and terpenoids. Flavonoids and coumarins have been shown to interact with the benzodiazepine site of the GABAA receptor and various voltage-gated ion channels, which are targets of synthetic AEDs. Modulation of the activity of ligand-gated and voltage-gated ion channels provides an explanatory basis of the anticonvulsant effects of plant secondary metabolites. Many complex extracts and single plant-derived compounds exhibit antiinflammatory, neuroprotective, and cognition-enhancing activities that may be beneficial in the treatment of epilepsy. Thus, botanicals provide a base for target-oriented antiepileptic drug discovery and development. In the future, preclinical work should focus on the characterization of the effects of plant extracts and plant-derived compounds on well-defined targets rather than on phenotypic screening using in vivo animal models of acute seizures. At the same time, available data provide ample justification for clinical studies with selected standardized botanical extracts and plant-derived compounds. This article is part of a Special Issue entitled "Botanicals for Epilepsy".
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Affiliation(s)
- Nikolaus J Sucher
- Science Department, Roxbury Community College, MA, USA; FLAS, Northern Essex Community College, MA, USA; Biology Department, Salem State University, MA, USA.
| | - Maria C Carles
- Science Department, Roxbury Community College, MA, USA; FLAS, Northern Essex Community College, MA, USA; Biology Department, Salem State University, MA, USA
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23
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Davoren JE, Claffey MM, Snow SL, Reese MR, Arora G, Butler CR, Boscoe BP, Chenard L, DeNinno SL, Drozda SE, Duplantier AJ, Moine L, Rogers BN, Rong S, Schuyten K, Wright AS, Zhang L, Serpa KA, Weber ML, Stolyar P, Whisman TL, Baker K, Tse K, Clark AJ, Rong H, Mather RJ, Lowe JA. Discovery of a novel Kv7 channel opener as a treatment for epilepsy. Bioorg Med Chem Lett 2015; 25:4941-4944. [PMID: 25987375 DOI: 10.1016/j.bmcl.2015.04.074] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 04/18/2015] [Accepted: 04/21/2015] [Indexed: 01/11/2023]
Abstract
Facilitating activation, or delaying inactivation, of the native Kv7 channel reduces neuronal excitability, which may be beneficial in controlling spontaneous electrical activity during epileptic seizures. In an effort to identify a compound with such properties, the structure-activity relationship (SAR) and in vitro ADME for a series of heterocyclic Kv7.2-7.5 channel openers was explored. PF-05020182 (2) demonstrated suitable properties for further testing in vivo where it dose-dependently decreased the number of animals exhibiting full tonic extension convulsions in response to corneal stimulation in the maximal electroshock (MES) assay. In addition, PF-05020182 (2) significantly inhibited convulsions in the MES assay at doses tested, consistent with in vitro activity measure. The physiochemical properties, in vitro and in vivo activities of PF-05020182 (2) support further development as an adjunctive treatment of refractory epilepsy.
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Affiliation(s)
| | | | - Sheri L Snow
- Pfizer, Eastern Point Road, Groton, CT, United States
| | | | - Gaurav Arora
- Pfizer, Eastern Point Road, Groton, CT, United States
| | | | | | - Lois Chenard
- Pfizer, Eastern Point Road, Groton, CT, United States
| | | | | | | | | | | | - SuoBao Rong
- Pfizer, Eastern Point Road, Groton, CT, United States
| | | | - Ann S Wright
- Pfizer, Eastern Point Road, Groton, CT, United States
| | - Lei Zhang
- Pfizer, 610 Main Street, Cambridge, MA, United States
| | - Kevin A Serpa
- Pfizer, Eastern Point Road, Groton, CT, United States
| | - Mark L Weber
- Pfizer, Eastern Point Road, Groton, CT, United States
| | | | | | - Karen Baker
- Pfizer, Eastern Point Road, Groton, CT, United States
| | - Karen Tse
- Pfizer, Drug Safety Research & Development, Sandwich, United Kingdom
| | - Alan J Clark
- Pfizer, Eastern Point Road, Groton, CT, United States
| | - Haojing Rong
- Pfizer, Eastern Point Road, Groton, CT, United States
| | - Robert J Mather
- AstraZeneca Neuroscience iMED, 141 Portland St., Cambridge, MA, United States
| | - John A Lowe
- JL3Pharma LLC, 28 Cove Side Lane, Stonington, CT, United States.
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24
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Trimmer JS. Subcellular localization of K+ channels in mammalian brain neurons: remarkable precision in the midst of extraordinary complexity. Neuron 2015; 85:238-56. [PMID: 25611506 DOI: 10.1016/j.neuron.2014.12.042] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Potassium channels (KChs) are the most diverse ion channels, in part due to extensive combinatorial assembly of a large number of principal and auxiliary subunits into an assortment of KCh complexes. Their structural and functional diversity allows KChs to play diverse roles in neuronal function. Localization of KChs within specialized neuronal compartments defines their physiological role and also fundamentally impacts their activity, due to localized exposure to diverse cellular determinants of channel function. Recent studies in mammalian brain reveal an exquisite refinement of KCh subcellular localization. This includes axonal KChs at the initial segment, and near/within nodes of Ranvier and presynaptic terminals, dendritic KChs found at sites reflecting specific synaptic input, and KChs defining novel neuronal compartments. Painting the remarkable diversity of KChs onto the complex architecture of mammalian neurons creates an elegant picture of electrical signal processing underlying the sophisticated function of individual neuronal compartments, and ultimately neurotransmission and behavior.
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Affiliation(s)
- James S Trimmer
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA 95616, USA; Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA.
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25
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Treven M, Koenig X, Assadpour E, Gantumur E, Meyer C, Hilber K, Boehm S, Kubista H. The anticonvulsant retigabine is a subtype selective modulator of GABAA receptors. Epilepsia 2015; 56:647-57. [PMID: 25779225 PMCID: PMC4949651 DOI: 10.1111/epi.12950] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2015] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Within its range of therapeutic plasma concentrations, the anticonvulsant retigabine (ezogabine) is believed to selectively act on Kv7 channels. Here, the contribution of specific γ-aminobutyric acid (GABA)A receptor subtypes to the antiseizure effects of retigabine was investigated. METHODS Using patch-clamp recordings, seizure-like activity, tonic currents, and GABA-induced currents in hippocampal neurons were tested for their sensitivity toward retigabine, as were recombinant GABAA receptors expressed in tsA 201 cells. RESULTS Retigabine reduced seizure-like activity elicited by low Mg(2+) in a concentration-dependent manner with half maximal inhibition at 1 μm. Seizure-like activity triggered by blocking either Kv7 channels or GABAA receptors was equally reduced by retigabine, but when these channels/receptors were blocked simultaneously, the inhibition was lost. Retigabine (10 μm) enhanced bicuculline-sensitive tonic currents in hippocampal neurons, but failed to affect GABA-evoked currents. However, when receptors involved in phasic GABAergic inhibition were blocked by penicillin, retigabine did enhance GABA-evoked currents. In tsA 201 cells expressing various combinations of GABAA receptor subunits, 10 μm retigabine enhanced currents through α1β2δ, α4β2δ, α4β3δ, and α6β2δ receptors, but left currents through α1β2γ2S, α4β3γ2S, α5β3γ2S, and α6β2γ2S receptors unaltered. With αβ receptors, retigabine diminished currents through α1β2 and α4β3, but increased currents through α6β2 receptors. The enhancement of currents through α1β2δ receptors by retigabine was concentration dependent and became significant at 1 μm. SIGNIFICANCE These results demonstrate that retigabine is a subtype selective modulator of GABAA receptors with preference for extrasynaptic δ-containing receptors; this property may contribute to its broad antiepileptic effectiveness and explain its lack of effect on absence seizures.
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Affiliation(s)
- Marco Treven
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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Brueggemann LI, Haick JM, Cribbs LL, Byron KL. Differential activation of vascular smooth muscle Kv7.4, Kv7.5, and Kv7.4/7.5 channels by ML213 and ICA-069673. Mol Pharmacol 2014; 86:330-41. [PMID: 24944189 DOI: 10.1124/mol.114.093799] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Recent research suggests that smooth muscle cells express Kv7.4 and Kv7.5 voltage-activated potassium channels, which contribute to maintenance of their resting membrane voltage. New pharmacologic activators of Kv7 channels, ML213 (N-mesitybicyclo[2.2.1]heptane-2-carboxamide) and ICA-069673 N-(6-chloropyridin-3-yl)-3,4-difluorobenzamide), have been reported to discriminate among channels formed from different Kv7 subtypes. We compared the effects of ML213 and ICA-069673 on homomeric human Kv7.4, Kv7.5, and heteromeric Kv7.4/7.5 channels exogenously expressed in A7r5 vascular smooth muscle cells. We found that, despite its previous description as a selective activator of Kv7.2 and Kv7.4, ML213 significantly increased the maximum conductance of homomeric Kv7.4 and Kv7.5, as well as heteromeric Kv7.4/7.5 channels, and induced a negative shift of their activation curves. Current deactivation rates decreased in the presence of the ML213 (10 μM) for all three channel combinations. Mutants of Kv7.4 (W242L) and Kv7.5 (W235L), previously found to be insensitive to another Kv7 channel activator, retigabine, were also insensitive to ML213 (10 μM). In contrast to ML213, ICA-069673 robustly activated Kv7.4 channels but was significantly less effective on homomeric Kv7.5 channels. Heteromeric Kv7.4/7.5 channels displayed intermediate responses to ICA-069673. In each case, ICA-069673 induced a negative shift of the activation curves without significantly increasing maximal conductance. Current deactivation rates decreased in the presence of ICA-069673 in a subunit-specific manner. Kv7.4 W242L responded to ICA-069673-like wild-type Kv7.4, but a Kv7.4 F143A mutant was much less sensitive to ICA-069673. Based on these results, ML213 and ICA-069673 likely bind to different sites and are differentially selective among Kv7.4, Kv7.5, and Kv7.4/7.5 channel subtypes.
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Affiliation(s)
- Lyubov I Brueggemann
- Department of Molecular Pharmacology and Therapeutics (L.I.B., J.M.H., K.L.B.) and Cell and Molecular Physiology (L.L.C.); Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - Jennifer M Haick
- Department of Molecular Pharmacology and Therapeutics (L.I.B., J.M.H., K.L.B.) and Cell and Molecular Physiology (L.L.C.); Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - Leanne L Cribbs
- Department of Molecular Pharmacology and Therapeutics (L.I.B., J.M.H., K.L.B.) and Cell and Molecular Physiology (L.L.C.); Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - Kenneth L Byron
- Department of Molecular Pharmacology and Therapeutics (L.I.B., J.M.H., K.L.B.) and Cell and Molecular Physiology (L.L.C.); Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
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