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Hawashin A, Brakmann IC, Tian Y, Gründer S, Ortega-Ramírez AM. Modulation of Acid-Sensing Ion Channels by Tannic Acid and Green Tea via a Membrane-Mediated Mechanism. ACS Chem Neurosci 2023. [PMID: 37379568 DOI: 10.1021/acschemneuro.3c00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are proton-gated ion channels that contribute to pain perception and neurotransmission. Being involved in sensing inflammation and ischemia, ASIC1a and ASIC3 are promising drug targets. Polyphenol tannic acid (TA) as well as green tea can interact with a variety of ion channels, but their effect on ASICs remains unknown. In addition, it is unknown whether they interact with ion channels via a common mechanism. Here, we show that TA is a potent modulator of ASICs. TA inhibited the transient current of rat ASIC3 expressed in HEK cells with an apparent IC50 of 2.2 ± 0.6 μM; it potentiated the sustained current and induced a slowly declining decay current. In addition, it produced an acidic shift of the pH-dependent activation of ASIC3 and inhibited the window current at pH 7.0. Moreover, TA inhibited the transient current of ASIC1a, ASIC1b, and ASIC2a. Pentagalloylglucose that is chemically identical to the central part of TA and a green tea extract both had effects on ASIC3 comparable to TA. TA and green tea inhibited inward currents generated by gramicidin channels, indicating interaction with the membrane. These results show that TA, pentagalloylglucose, and green tea modulate ASICs and identify alteration of the membrane as the potential common mechanism of this modulation. These properties will limit clinical application of these molecules.
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Affiliation(s)
- Ammar Hawashin
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, Aachen D-52074, Germany
| | - Ilka C Brakmann
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, Aachen D-52074, Germany
| | - Yuemin Tian
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, Aachen D-52074, Germany
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, Aachen D-52074, Germany
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Manville RW, Alfredo Freites J, Sidlow R, Tobias DJ, Abbott GW. Native American ataxia medicines rescue ataxia-linked mutant potassium channel activity via binding to the voltage sensing domain. Nat Commun 2023; 14:3281. [PMID: 37280215 DOI: 10.1038/s41467-023-38834-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 05/17/2023] [Indexed: 06/08/2023] Open
Abstract
There are currently no drugs known to rescue the function of Kv1.1 voltage-gated potassium channels carrying loss-of-function sequence variants underlying the inherited movement disorder, Episodic Ataxia 1 (EA1). The Kwakwaka'wakw First Nations of the Pacific Northwest Coast used Fucus gardneri (bladderwrack kelp), Physocarpus capitatus (Pacific ninebark) and Urtica dioica (common nettle) to treat locomotor ataxia. Here, we show that extracts of these plants enhance wild-type Kv1.1 current, especially at subthreshold potentials. Screening of their constituents revealed that gallic acid and tannic acid similarly augment wild-type Kv1.1 current, with submicromolar potency. Crucially, the extracts and their constituents also enhance activity of Kv1.1 channels containing EA1-linked sequence variants. Molecular dynamics simulations reveal that gallic acid augments Kv1.1 activity via a small-molecule binding site in the extracellular S1-S2 linker. Thus, traditional Native American ataxia treatments utilize a molecular mechanistic foundation that can inform small-molecule approaches to therapeutically correcting EA1 and potentially other Kv1.1-linked channelopathies.
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Affiliation(s)
- Rían W Manville
- Bioelectricity Laboratory, Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | | | | | - Douglas J Tobias
- Department of Chemistry, University of California, Irvine, CA, USA
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA.
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Manville RW, Redford KE, van der Horst J, Hogenkamp DJ, Jepps TA, Abbott GW. KCNQ5 activation by tannins mediates vasorelaxant effects of barks used in Native American botanical medicine. FASEB J 2022; 36:e22457. [PMID: 35997997 PMCID: PMC9404676 DOI: 10.1096/fj.202200724r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/30/2022] [Accepted: 07/06/2022] [Indexed: 11/11/2022]
Abstract
Tree and shrub barks have been used as folk medicine by numerous cultures across the globe for millennia, for a variety of indications, including as vasorelaxants and antispasmodics. Here, using electrophysiology and myography, we discovered that the KCNQ5 voltage-gated potassium channel mediates vascular smooth muscle relaxant effects of barks used in Native American folk medicine. Bark extracts (1%) from Birch, Cramp Bark, Slippery Elm, White Oak, Red Willow, White Willow, and Wild Cherry each strongly activated KCNQ5 expressed in Xenopus oocytes. Testing of a subset including both the most and the least efficacious extracts revealed that Red Willow, White Willow, and White Oak KCNQ-dependently relaxed rat mesenteric arteries; in contrast, Black Haw bark neither activated KCNQ5 nor induced vasorelaxation. Two compounds common to the active barks (gallic acid and tannic acid) had similarly potent and efficacious effects on both KCNQ5 activation and vascular relaxation, and this together with KCNQ5 modulation by other tannins provides a molecular basis for smooth muscle relaxation effects of Native American folk medicine bark extracts.
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Affiliation(s)
- Rian W. Manville
- Bioelectricity Laboratory, Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Kaitlyn E. Redford
- Bioelectricity Laboratory, Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Jennifer van der Horst
- Department of Biomedical Sciences, Vascular Biology Group, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Derk J. Hogenkamp
- Bioelectricity Laboratory, Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Thomas A. Jepps
- Department of Biomedical Sciences, Vascular Biology Group, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Geoffrey W. Abbott
- Bioelectricity Laboratory, Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
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Abstract
Voltage-gated potassium (Kv) channels each comprise four pore-forming α-subunits that orchestrate essential duties such as voltage sensing and K+ selectivity and conductance. In vivo, however, Kv channels also incorporate regulatory subunits-some Kv channel specific, others more general modifiers of protein folding, trafficking, and function. Understanding all the above is essential for a complete picture of the role of Kv channels in physiology and disease.
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Affiliation(s)
- Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
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Bauer CK, Holling T, Horn D, Laço MN, Abdalla E, Omar OM, Alawi M, Kutsche K. Clinically Relevant KCNQ1 Variants Causing KCNQ1-KCNE2 Gain-of-Function Affect the Ca2+ Sensitivity of the Channel. Int J Mol Sci 2022; 23:ijms23179690. [PMID: 36077086 PMCID: PMC9456291 DOI: 10.3390/ijms23179690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/18/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
Dominant KCNQ1 variants are well-known for underlying cardiac arrhythmia syndromes. The two heterozygous KCNQ1 missense variants, R116L and P369L, cause an allelic disorder characterized by pituitary hormone deficiency and maternally inherited gingival fibromatosis. Increased K+ conductance upon co-expression of KCNQ1 mutant channels with the beta subunit KCNE2 is suggested to underlie the phenotype; however, the reason for KCNQ1-KCNE2 (Q1E2) channel gain-of-function is unknown. We aimed to discover the genetic defect in a single individual and three family members with gingival overgrowth and identified the KCNQ1 variants P369L and V185M, respectively. Patch-clamp experiments demonstrated increased constitutive K+ conductance of V185M-Q1E2 channels, confirming the pathogenicity of the novel variant. To gain insight into the pathomechanism, we examined all three disease-causing KCNQ1 mutants. Manipulation of the intracellular Ca2+ concentration prior to and during whole-cell recordings identified an impaired Ca2+ sensitivity of the mutant KCNQ1 channels. With low Ca2+, wild-type KCNQ1 currents were efficiently reduced and exhibited a pre-pulse-dependent cross-over of current traces and a high-voltage-activated component. These features were absent in mutant KCNQ1 channels and in wild-type channels co-expressed with calmodulin and exposed to high intracellular Ca2+. Moreover, co-expression of calmodulin with wild-type Q1E2 channels and loading the cells with high Ca2+ drastically increased Q1E2 current amplitudes, suggesting that KCNE2 normally limits the resting Q1E2 conductance by an increased demand for calcified calmodulin to achieve effective channel opening. Our data link impaired Ca2+ sensitivity of the KCNQ1 mutants R116L, V185M and P369L to Q1E2 gain-of-function that is associated with a particular KCNQ1 channelopathy.
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Affiliation(s)
- Christiane K. Bauer
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- Correspondence:
| | - Tess Holling
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Denise Horn
- Department of Medical Genetics and Human Genetics, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt Universität zu Berlin and Berlin Institute of Health, 13353 Berlin, Germany
| | - Mário Nôro Laço
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, 3004-561 Coimbra, Portugal
| | - Ebtesam Abdalla
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria 5422031, Egypt
- Genetics Department, Armed Forces College of Medicine (AFCM), Cairo 4460015, Egypt
| | - Omneya Magdy Omar
- Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria 5422031, Egypt
| | - Malik Alawi
- Bioinformatics Core, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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Singh SP, William M, Malavia M, Chu XP. Behavior of KCNQ Channels in Neural Plasticity and Motor Disorders. Membranes 2022; 12:membranes12050499. [PMID: 35629827 PMCID: PMC9143857 DOI: 10.3390/membranes12050499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/26/2022] [Accepted: 05/03/2022] [Indexed: 02/01/2023]
Abstract
The broad distribution of voltage-gated potassium channels (VGKCs) in the human body makes them a critical component for the study of physiological and pathological function. Within the KCNQ family of VGKCs, these aqueous conduits serve an array of critical roles in homeostasis, especially in neural tissue. Moreover, the greater emphasis on genomic identification in the past century has led to a growth in literature on the role of the ion channels in pathological disease as well. Despite this, there is a need to consolidate the updated findings regarding both the pharmacotherapeutic and pathological roles of KCNQ channels, especially regarding neural plasticity and motor disorders which have the largest body of literature on this channel. Specifically, KCNQ channels serve a remarkable role in modulating the synaptic efficiency required to create appropriate plasticity in the brain. This role can serve as a foundation for clinical approaches to chronic pain. Additionally, KCNQ channels in motor disorders have been utilized as a direction for contemporary pharmacotherapeutic developments due to the muscarinic properties of this channel. The aim of this study is to provide a contemporary review of the behavior of these channels in neural plasticity and motor disorders. Upon review, the behavior of these channels is largely dependent on the physiological role that KCNQ modulatory factors (i.e., pharmacotherapeutic options) serve in pathological diseases.
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Czigle S, Bittner Fialová S, Tóth J, Mučaji P, Nagy M. Treatment of Gastrointestinal Disorders-Plants and Potential Mechanisms of Action of Their Constituents. Molecules 2022; 27:2881. [PMID: 35566230 PMCID: PMC9105531 DOI: 10.3390/molecules27092881] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/19/2022] [Accepted: 04/26/2022] [Indexed: 11/16/2022] Open
Abstract
The worldwide prevalence of gastrointestinal diseases is about 40%, with standard pharmacotherapy being long-lasting and economically challenging. Of the dozens of diseases listed by the Rome IV Foundation criteria, for five of them (heartburn, dyspepsia, nausea and vomiting disorder, constipation, and diarrhoea), treatment with herbals is an official alternative, legislatively supported by the European Medicines Agency (EMA). However, for most plants, the Directive does not require a description of the mechanisms of action, which should be related to the therapeutic effect of the European plant in question. This review article, therefore, summarizes the basic pharmacological knowledge of synthetic drugs used in selected functional gastrointestinal disorders (FGIDs) and correlates them with the constituents of medicinal plants. Therefore, the information presented here is intended as a starting point to support the claim that both empirical folk medicine and current and decades-old treatments with official herbal remedies have a rational basis in modern pharmacology.
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Affiliation(s)
- Szilvia Czigle
- Department of Pharmacognosy and Botany, Faculty of Pharmacy, Comenius University Bratislava, Odbojárov 10, SK-832 32 Bratislava, Slovakia; (S.B.F.); (J.T.); (P.M.); (M.N.)
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