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Van NTH, Kim WK, Nam JH. Challenges in the Therapeutic Targeting of KCa Channels: From Basic Physiology to Clinical Applications. Int J Mol Sci 2024; 25:2965. [PMID: 38474212 PMCID: PMC10932353 DOI: 10.3390/ijms25052965] [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: 12/15/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 03/14/2024] Open
Abstract
Calcium-activated potassium (KCa) channels are ubiquitously expressed throughout the body and are able to regulate membrane potential and intracellular calcium concentrations, thereby playing key roles in cellular physiology and signal transmission. Consequently, it is unsurprising that KCa channels have been implicated in various diseases, making them potential targets for pharmaceutical interventions. Over the past two decades, numerous studies have been conducted to develop KCa channel-targeting drugs, including those for disorders of the central and peripheral nervous, cardiovascular, and urinary systems and for cancer. In this review, we synthesize recent findings regarding the structure and activating mechanisms of KCa channels. We also discuss the role of KCa channel modulators in therapeutic medicine. Finally, we identify the major reasons behind the delay in bringing these modulators to the pharmaceutical market and propose new strategies to promote their application.
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Affiliation(s)
- Nhung Thi Hong Van
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
| | - Woo Kyung Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
- Department of Internal Medicine, Graduate School of Medicine, Dongguk University, Goyang 10326, Republic of Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
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2
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Olivas-Aguirre M, Cruz-Aguilar LH, Pottosin I, Dobrovinskaya O. Reduction of Ca 2+ Entry by a Specific Block of KCa3.1 Channels Optimizes Cytotoxic Activity of NK Cells against T-ALL Jurkat Cells. Cells 2023; 12:2065. [PMID: 37626875 PMCID: PMC10453324 DOI: 10.3390/cells12162065] [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: 06/09/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
Degranulation mediated killing mechanism by NK cells is dependent on store-operated Ca2+ entry (SOCE) and has optimum at moderate intracellular Ca2+ elevations so that partial block of SOCE optimizes the killing process. In this study, we tested the effect of the selective blocker of KCa3.1 channel NS6180 on SOCE and the killing efficiency of NK cells from healthy donors and NK-92 cells against T-ALL cell line Jurkat. Patch-clamp analysis showed that only one-quarter of resting NK cells functionally express KCa3.1 current, which increases 3-fold after activation by interleukins 15 and 2. Nevertheless, blockage of KCa3.1 significantly reduced SOCE and intracellular Ca2+ rise induced by IL-15 or target cell recognition. NS6180 (1 μM) decreased NK degranulation at zero time of coculture with Jurkat cells but already after 1 h, the degranulation reached the same level as in the control. Monitoring of target cell death by flow cytometry and confocal microscopy demonstrated that NS6180 significantly improved the killing ability of NK cells after 1 h in coculture with Jurkat cells and increased the Jurkat cell fraction with apoptotic and necrotic markers. Our data evidence a strong dependence of SOCE on KCa3.1 activity in NK cells and that KCa3.1 specific block can improve NK cytotoxicity.
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Affiliation(s)
- Miguel Olivas-Aguirre
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima 28045, Mexico
- Division of Exact, Natural and Technological Sciences, South University Center (CUsur), University of Guadalajara, Guzmán City 49000, Mexico
| | - Laura Hadit Cruz-Aguilar
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima 28045, Mexico
| | - Igor Pottosin
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima 28045, Mexico
| | - Oxana Dobrovinskaya
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima 28045, Mexico
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3
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Feng J, Xie Z, Hu H. Ion channel regulation of gut immunity. J Gen Physiol 2022; 155:213734. [PMID: 36459135 PMCID: PMC9723512 DOI: 10.1085/jgp.202113042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 08/15/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022] Open
Abstract
Mounting evidence indicates that gastrointestinal (GI) homeostasis hinges on communications among many cellular networks including the intestinal epithelium, the immune system, and both intrinsic and extrinsic nerves innervating the gut. The GI tract, especially the colon, is the home base for gut microbiome which dynamically regulates immune function. The gut's immune system also provides an effective defense against harmful pathogens entering the GI tract while maintaining immune homeostasis to avoid exaggerated immune reaction to innocuous food and commensal antigens which are important causes of inflammatory disorders such as coeliac disease and inflammatory bowel diseases (IBD). Various ion channels have been detected in multiple cell types throughout the GI tract. By regulating membrane properties and intracellular biochemical signaling, ion channels play a critical role in synchronized signaling among diverse cellular components in the gut that orchestrates the GI immune response. This work focuses on the role of ion channels in immune cells, non-immune resident cells, and neuroimmune interactions in the gut at the steady state and pathological conditions. Understanding the cellular and molecular basis of ion channel signaling in these immune-related pathways and initial testing of pharmacological intervention will facilitate the development of ion channel-based therapeutic approaches for the treatment of intestinal inflammation.
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Affiliation(s)
- Jing Feng
- Department of Anesthesiology, The Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO,Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Science, Shanghai, China,Correspondence to Jing Feng:
| | - Zili Xie
- Department of Anesthesiology, The Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO
| | - Hongzhen Hu
- Department of Anesthesiology, The Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO,Hongzhen Hu:
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4
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Cosme D, Soares-da-Silva P, Magro F. Effect of Toll-like receptor-2, -4, -5, -7, and NOD2 stimulation on potassium channel conductance in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2022; 323:G410-G419. [PMID: 36040119 DOI: 10.1152/ajpgi.00139.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Disproportionate activation of pattern recognition receptors plays a role in inflammatory bowel disease (IBD) pathophysiology. Diarrhea is a hallmark symptom of IBD, resulting at least in part from an electrolyte imbalance that may be caused by changes in potassium channel activity. We evaluated the impact of Toll-like receptors (TLRs) and nucleotide-binding oligomerization domain 2 (NOD2) stimulation on potassium conductance of the basolateral membrane in human intestinal epithelial cells (IECs) and the role of potassium channels through electrophysiological assays under short-circuit current in Ussing chambers. TLRs and NOD2 were stimulated using specific agonists, and potassium channels were selectively blocked using triarylmethane-34 (TRAM-34), adenylyl-imidodiphosphate (AMP-PNP), and BaCl2. Potassium conductance of the basolateral membrane decreased upon activation of TLR2, TLR4, and TLR7 in T84 cells (means ± SE, -11.2 ± 4.5, -40.4 ± 7.2, and -19.4 ± 5.9, respectively) and in Caco-2 cells (-13.1 ± 5.7, -55.7 ± 7.4, and -29.1 ± 7.2, respectively). In contrast, activation of TLR5 and NOD2 increased basolateral potassium conductance, both in T84 cells (18.0 ± 4.1 and 18.4 ± 2.8, respectively) and in Caco-2 cells (21.2 ± 8.4 and 16.0 ± 3.6, respectively). TRAM-34 and AMP-PNP induced a decrease in basolateral potassium conductance upon TLR4 stimulation in both cell lines. Both KCa3.1- and Kir6-channels appear to be important mediators of this effect in IECs and could be potential targets for therapeutic agent development.NEW & NOTEWORTHY This study highlights that PRRs stimulation directly influences K+-channel conductance in IECs. TLR-2, -4, -7 stimulation decreased K+ conductance, whereas TLR5 and NOD2 stimulation had the opposite effect, leading to an increase of it instead. This study reports for the first time that KCa3.1- and Kir6-channels play a role in K+ transport pathways triggered by TLR4 stimulation. These findings suggest that KCa3.1- and Kir6-channels modulation may be a potential target for new therapeutic agents in IBD.
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Affiliation(s)
- Dina Cosme
- Unit of Pharmacology and Therapeutics, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal.,MedInUP, Center for Drug Discovery and Innovative Medicines, Porto, Portugal
| | - Patrício Soares-da-Silva
- Unit of Pharmacology and Therapeutics, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal.,MedInUP, Center for Drug Discovery and Innovative Medicines, Porto, Portugal
| | - Fernando Magro
- Unit of Pharmacology and Therapeutics, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal.,Department of Gastroenterology, São João Hospital University Centre, Porto, Portugal.,Center for Health Technology and Services Research, Porto, Portugal.,Clinical Pharmacology Unit, São João Hospital University Centre, Porto, Portugal.,Portuguese Inflammatory Bowel Disease Group, Porto, Portugal
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5
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Selezneva A, Gibb AJ, Willis D. The contribution of ion channels to shaping macrophage behaviour. Front Pharmacol 2022; 13:970234. [PMID: 36160429 PMCID: PMC9490177 DOI: 10.3389/fphar.2022.970234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/15/2022] [Indexed: 11/25/2022] Open
Abstract
The expanding roles of macrophages in physiological and pathophysiological mechanisms now include normal tissue homeostasis, tissue repair and regeneration, including neuronal tissue; initiation, progression, and resolution of the inflammatory response and a diverse array of anti-microbial activities. Two hallmarks of macrophage activity which appear to be fundamental to their diverse cellular functionalities are cellular plasticity and phenotypic heterogeneity. Macrophage plasticity allows these cells to take on a broad spectrum of differing cellular phenotypes in response to local and possibly previous encountered environmental signals. Cellular plasticity also contributes to tissue- and stimulus-dependent macrophage heterogeneity, which manifests itself as different macrophage phenotypes being found at different tissue locations and/or after different cell stimuli. Together, plasticity and heterogeneity align macrophage phenotypes to their required local cellular functions and prevent inappropriate activation of the cell, which could lead to pathology. To execute the appropriate function, which must be regulated at the qualitative, quantitative, spatial and temporal levels, macrophages constantly monitor intracellular and extracellular parameters to initiate and control the appropriate cell signaling cascades. The sensors and signaling mechanisms which control macrophages are the focus of a considerable amount of research. Ion channels regulate the flow of ions between cellular membranes and are critical to cell signaling mechanisms in a variety of cellular functions. It is therefore surprising that the role of ion channels in the macrophage biology has been relatively overlooked. In this review we provide a summary of ion channel research in macrophages. We begin by giving a narrative-based explanation of the membrane potential and its importance in cell biology. We then report on research implicating different ion channel families in macrophage functions. Finally, we highlight some areas of ion channel research in macrophages which need to be addressed, future possible developments in this field and therapeutic potential.
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6
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Laska MJ, Møller JB, Graversen JH, Strøbæk D, Blomster L, Christophersen P, Bahrami S. Retroviral glycoprotein-mediated immune suppression via the potassium channel KCa3.1 - A new strategy for amelioration of inflammatory bowel diseases. Clin Immunol 2022; 242:109081. [PMID: 35905828 DOI: 10.1016/j.clim.2022.109081] [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: 04/21/2022] [Revised: 07/01/2022] [Accepted: 07/20/2022] [Indexed: 11/03/2022]
Abstract
Peptides derived from retroviral envelope proteins have been shown to possess a wide range of immunosuppressive and anti-inflammatory activities. We have previously reported identification of such a peptide derived from the envelope protein coded by a human endogenous retrovirus (HERV). In this study, we identified that in vitro the peptide inhibits the KCa3.1 potassium channel, a potential target for therapy of immune diseases. We describe in vitro ENV59-GP3 effects with respect to potency of inhibition on KCa3.1 channels and calcium influx. Furthermore, we asses in vivo the effect of blocking KCa3.1 with ENV59-GP3 peptide or KCa3.1-blocker NS6180 on protection against DSS-induced acute colitis. ENV59-GP3 peptide treatment showed reduction of the disease score in the DSS-induced acute colitis mice model, which was comparable to effects of the KCa3.1 channel blocker NS6180. Analysis of cytokine production from DSS-mice model treated animals revealed equipotent inhibitory effects of the ENV59-GP3 and NS6180 compounds on the production of IL-6, TNF-α, IL-1β. These findings altogether suggest that ENV59-GP3 functions as a KCa3.1 channel inhibitor and underline the implications of using virus derived channel blockers for treatment of autoimmune diseases. Additionally, they open the possibilities whether KCa3.1 inhibition is efficacious in patients with inflammatory bowel diseases.
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Affiliation(s)
- Magdalena J Laska
- Department of Molecular Biology and Genetics, Aarhus University, Denmark.
| | - Jesper Bonnet Møller
- Department of Cancer and Inflammation Research, University of Southern Denmark, Denmark
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7
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Shim H, Kim H, Allen JE, Wulff H. Pose Classification Using Three-Dimensional Atomic Structure-Based Neural Networks Applied to Ion Channel-Ligand Docking. J Chem Inf Model 2022; 62:2301-2315. [PMID: 35447030 PMCID: PMC9131459 DOI: 10.1021/acs.jcim.1c01510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Indexed: 12/11/2022]
Abstract
The identification of promising lead compounds showing pharmacological activities toward a biological target is essential in early stage drug discovery. With the recent increase in available small-molecule databases, virtual high-throughput screening using physics-based molecular docking has emerged as an essential tool in assisting fast and cost-efficient lead discovery and optimization. However, the best scored docking poses are often suboptimal, resulting in incorrect screening and chemical property calculation. We address the pose classification problem by leveraging data-driven machine learning approaches to identify correct docking poses from AutoDock Vina and Glide screens. To enable effective classification of docking poses, we present two convolutional neural network approaches: a three-dimensional convolutional neural network (3D-CNN) and an attention-based point cloud network (PCN) trained on the PDBbind refined set. We demonstrate the effectiveness of our proposed classifiers on multiple evaluation data sets including the standard PDBbind CASF-2016 benchmark data set and various compound libraries with structurally different protein targets including an ion channel data set extracted from Protein Data Bank (PDB) and an in-house KCa3.1 inhibitor data set. Our experiments show that excluding false positive docking poses using the proposed classifiers improves virtual high-throughput screening to identify novel molecules against each target protein compared to the initial screen based on the docking scores.
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Affiliation(s)
- Heesung Shim
- Department
of Pharmacology, University of California, Davis, California 95616, United States
| | - Hyojin Kim
- Center
for Applied Scientific Computing, Lawrence
Livermore National Laboratory, Livermore, California 94550, United States
| | - Jonathan E. Allen
- Global
Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Heike Wulff
- Department
of Pharmacology, University of California, Davis, California 95616, United States
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8
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Sahu G, Turner RW. The Molecular Basis for the Calcium-Dependent Slow Afterhyperpolarization in CA1 Hippocampal Pyramidal Neurons. Front Physiol 2022; 12:759707. [PMID: 35002757 PMCID: PMC8730529 DOI: 10.3389/fphys.2021.759707] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/01/2021] [Indexed: 12/02/2022] Open
Abstract
Neuronal signal transmission depends on the frequency, pattern, and timing of spike output, each of which are shaped by spike afterhyperpolarizations (AHPs). There are classically three post-spike AHPs of increasing duration categorized as fast, medium and slow AHPs that hyperpolarize a cell over a range of 10 ms to 30 s. Intensive early work on CA1 hippocampal pyramidal cells revealed that all three AHPs incorporate activation of calcium-gated potassium channels. The ionic basis for a fAHP was rapidly attributed to the actions of big conductance (BK) and the mAHP to small conductance (SK) or Kv7 potassium channels. In stark contrast, the ionic basis for a prominent slow AHP of up to 30 s duration remained an enigma for over 30 years. Recent advances in pharmacological, molecular, and imaging tools have uncovered the expression of a calcium-gated intermediate conductance potassium channel (IK, KCa3.1) in central neurons that proves to contribute to the slow AHP in CA1 hippocampal pyramidal cells. Together the data show that the sAHP arises in part from a core tripartite complex between Cav1.3 (L-type) calcium channels, ryanodine receptors, and IK channels at endoplasmic reticulum-plasma membrane junctions. Work on the sAHP in CA1 pyramidal neurons has again quickened pace, with identified contributions by both IK channels and the Na-K pump providing answers to several mysteries in the pharmacological properties of the sAHP.
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Affiliation(s)
- Giriraj Sahu
- National Institute of Pharmaceutical Education and Research Ahmedabad, Ahmedabad, India
| | - Ray W Turner
- Department Cell Biology & Anatomy, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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9
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Garland CJ, Dora KA. Endothelium-Dependent Hyperpolarization: The Evolution of Myoendothelial Microdomains. J Cardiovasc Pharmacol 2021; 78:S3-S12. [PMID: 34840265 DOI: 10.1097/fjc.0000000000001087] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 05/29/2021] [Indexed: 10/19/2022]
Abstract
ABSTRACT Endothelium-derived hyperpolarizing factor (EDHF) was envisaged as a chemical entity causing vasodilation by hyperpolarizing vascular smooth muscle (VSM) cells and distinct from nitric oxide (NO) ([aka endothelium-derived relaxing factor (EDRF)]) and prostacyclin. The search for an identity for EDHF unraveled the complexity of signaling within small arteries. Hyperpolarization originates within endothelial cells (ECs), spreading to the VSM by 2 branches, 1 chemical and 1 electrical, with the relative contribution varying with artery location, branch order, and prevailing profile of VSM activation. Chemical signals vary likewise and can involve potassium ion, lipid mediators, and hydrogen peroxide, whereas electrical signaling depends on physical contacts formed by homocellular and heterocellular (myoendothelial; MEJ) gap junctions, both able to conduct hyperpolarizing current. The discovery that chemical and electrical signals each arise within ECs resulted in an evolution of the single EDHF concept into the more inclusive, EDH signaling. Recognition of the importance of MEJs and particularly the fact they can support bidirectional signaling also informed the discovery that Ca2+ signals can pass from VSM to ECs during vasoconstriction. This signaling activates negative feedback mediated by NO and EDH forming a myoendothelial feedback circuit, which may also be responsible for basal or constitutive release of NO and EDH activity. The MEJs are housed in endothelial projections, and another spin-off from investigating EDH signaling was the discovery these fine structures contain clusters of signaling proteins to regulate both hyperpolarization and NO release. So, these tiny membrane bridges serve as a signaling superhighway or infobahn, which controls vasoreactivity by responding to signals flowing back and forth between the endothelium and VSM. By allowing bidirectional signaling, MEJs enable sinusoidal vasomotion, co-ordinated cycles of widespread vasoconstriction/vasodilation that optimize time-averaged blood flow. Cardiovascular disease disrupts EC signaling and as a result vasomotion changes to vasospasm.
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10
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Cui X, Li X, He Y, Yu J, Fu J, Song B, Zhao RC. Combined NOX/ROS/PKC Signaling Pathway and Metabolomic Analysis Reveals the Mechanism of TRAM34-Induced Endothelial Progenitor Cell Senescence. Stem Cells Dev 2021; 30:671-682. [PMID: 33906436 DOI: 10.1089/scd.2021.0062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
It has been shown that the KCa3.1 channel-specific blocker, TRAM34, is a promising antiatherosclerosis (AS) agent, but its side effects restrict its clinical application. Notably, its effect on endothelial progenitor cells (EPCs) is unclear. We aim to unravel the effect of TRAM34 on EPCs and identify the underlying mechanism. Rats were injected intraperitoneally with TRAM34, and EPCs were isolated from bone marrow. The gene and protein levels of corresponding factors were detected by real-time PCR, enzyme-linked immunosorbent assay, western blotting, and fluorescence-activated cell sorting. Liquid chromatography-tandem mass spectrometry (LC-MS) was applied to detect metabolite differences. We showed that when rats were treated with TRAM34 in vivo, colony formation and proliferation of early EPCs were reduced, but their senescence and apoptosis were enhanced. Moreover, TRAM34 enhanced NOX activity, promoted an increase in intracellular ROS levels, increased PKC expression, and subsequently promoted EPC senescence, which is unfavorable for EPC angiogenesis in vivo and in vitro. Combining these results with LC-MS data, we found that TRAM34 significantly promoted pyrimidine and purine metabolism, leading to cellular senescence. Furthermore, the NOX inhibitor, Setanaxib, enhanced antioxidant metabolic pathways, especially S-adenosylmethioninamine (SAM) metabolism, to exert an antisenescence effect. Finally, we confirmed that SAM alleviates TRAM34-induced cellular senescence, suggesting an efficient approach to improve the quality of endogenous EPCs. This study reveals the mechanism of TRAM34-induced EPC senescence, providing a solution for the extended application of KCa3.1 inhibitor in AS.
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Affiliation(s)
- Xiaodong Cui
- Department of Basic Medicine, Institute of Stem Cell and Regenerative Medicine, Qingdao University Medical College, Qingdao University, Qingdao, P.R. China.,School of Basic Medical Sciences, Weifang Medical University, Weifang, P.R. China
| | - Xiaoxia Li
- Department of Basic Medicine, Institute of Stem Cell and Regenerative Medicine, Qingdao University Medical College, Qingdao University, Qingdao, P.R. China
| | - Yanting He
- School of Basic Medical Sciences, Weifang Medical University, Weifang, P.R. China
| | - Jie Yu
- School of Basic Medical Sciences, Weifang Medical University, Weifang, P.R. China
| | - Jie Fu
- School of Basic Medical Sciences, Weifang Medical University, Weifang, P.R. China
| | - Bo Song
- School of Pharmacy, Weifang Medical University, Weifang, P.R. China
| | - Robert Chunhua Zhao
- Department of Basic Medicine, Institute of Stem Cell and Regenerative Medicine, Qingdao University Medical College, Qingdao University, Qingdao, P.R. China
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11
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Manfroni G, Ragonese F, Monarca L, Astolfi A, Mancinelli L, Iannitti RG, Bastioli F, Barreca ML, Cecchetti V, Fioretti B. New Insights on KCa3.1 Channel Modulation. Curr Pharm Des 2020; 26:2096-2101. [PMID: 32175839 DOI: 10.2174/1381612826666200316152645] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/11/2020] [Indexed: 11/22/2022]
Abstract
The human intermediate conductance calcium-activated potassium channel, KCa3.1, is involved in several pathophysiological conditions playing a critical role in cell secretory machinery and calcium signalling. The recent cryo-EM analysis provides new insights for understanding the modulation by both endogenous and pharmacological agents. A typical feature of this channel is the low open probability in saturating calcium concentrations and its modulation by potassium channel openers (KCOs), such as benzo imidazolone 1-EBIO, without changing calcium-dependent activation. In this paper, we proposed a model of KCOs action in the modulation of channel activity. The KCa3.1 channel has a very rich pharmacological profile with several classes of molecules that selectively interact with different binding sites of the channel. Among them, benzo imidazolones can be openers (positive modulators such as 1-EBIO, DC-EBIO) or blockers (negative modulators such as NS1619). Through computation modelling techniques, we identified the 1,4-benzothiazin-3-one as a promising scaffold to develop new KCa3.1 channel modulators. Further studies are needed to explore the potential use of 1-4 benzothiazine- 3-one in KCa3.1 modulation and its pharmacological application.
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Affiliation(s)
- Giuseppe Manfroni
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1-06123-Perugia (PG), Italy
| | - Francesco Ragonese
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.,Department of Experimental Medicine, Perugia Medical School, University of Perugia, Piazza Lucio Severi 1, 06132 Perugia, Italy
| | - Lorenzo Monarca
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.,Department of Experimental Medicine, Perugia Medical School, University of Perugia, Piazza Lucio Severi 1, 06132 Perugia, Italy
| | - Andrea Astolfi
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1-06123-Perugia (PG), Italy
| | - Loretta Mancinelli
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | | | | | - Maria L Barreca
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1-06123-Perugia (PG), Italy
| | - Violetta Cecchetti
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1-06123-Perugia (PG), Italy
| | - Bernard Fioretti
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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12
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Kloza M, Baranowska-Kuczko M, Toczek M, Kusaczuk M, Sadowska O, Kasacka I, Kozłowska H. Modulation of Cardiovascular Function in Primary Hypertension in Rat by SKA-31, an Activator of KCa2.x and KCa3.1 Channels. Int J Mol Sci 2019; 20:ijms20174118. [PMID: 31450834 PMCID: PMC6747311 DOI: 10.3390/ijms20174118] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/17/2019] [Accepted: 08/21/2019] [Indexed: 12/11/2022] Open
Abstract
The aim of this study was to investigate the hemodynamic effects of SKA-31, an activator of the small (KCa2.x) and intermediate (KCa3.1) conductance calcium-activated potassium channels, and to evaluate its influence on endothelium-derived hyperpolarization (EDH)-KCa2.3/KCa3.1 type relaxation in isolated endothelium-intact small mesenteric arteries (sMAs) from spontaneously hypertensive rats (SHRs). Functional in vivo and in vitro experiments were performed on SHRs or their normotensive controls, Wistar-Kyoto rats (WKY). SKA-31 (1, 3 and 10 mg/kg) caused a brief decrease in blood pressure and bradycardia in both SHR and WKY rats. In phenylephrine-pre-constricted sMAs of SHRs, SKA-31 (0.01–10 µM)-mediated relaxation was reduced and SKA-31 potentiated acetylcholine-evoked endothelium-dependent relaxation. Endothelium denudation and inhibition of nitric oxide synthase (eNOS) and cyclooxygenase (COX) by the respective inhibitors l-NAME or indomethacin, attenuated SKA-31-mediated vasorelaxation. The inhibition of KCa3.1, KCa2.3, KIR and Na+/K+-ATPase by TRAM-34, UCL1684, Ba2+ and ouabain, respectively, reduced the potency and efficacy of the EDH-response evoked by SKA-31. The mRNA expression of eNOS, prostacyclin synthase, KCa2.3, KCa3.1 and KIR were decreased, while Na+/K+-ATPase expression was increased. Collectively, SKA-31 promoted hypotension and vasodilatation, potentiated agonist-stimulated vasodilation, and maintained KCa2.3/KCa3.1-EDH-response in sMAs of SHR with downstream signaling that involved KIR and Na+/K+-ATPase channels. In view of the importance of the dysfunction of endothelium-mediated vasodilatation in the mechanism of hypertension, application of activators of KCa2.3/KCa3.1 channels such as SKA-31 seem to be a promising avenue in pharmacotherapy of hypertension.
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Affiliation(s)
- Monika Kloza
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland
| | - Marta Baranowska-Kuczko
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland
- Department of Clinical Pharmacy, Medical University of Białystok, 15-222 Białystok, Poland
| | - Marek Toczek
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland
| | - Magdalena Kusaczuk
- Department of Pharmaceutical Biochemistry, Medical University of Białystok, 15-222 Białystok, Poland
| | - Olga Sadowska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland
| | - Irena Kasacka
- Department of Histology and Cytophysiology, Medical University of Białystok, 15-222 Białystok, Poland
| | - Hanna Kozłowska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland.
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13
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Brown BM, Shim H, Christophersen P, Wulff H. Pharmacology of Small- and Intermediate-Conductance Calcium-Activated Potassium Channels. Annu Rev Pharmacol Toxicol 2019; 60:219-240. [PMID: 31337271 DOI: 10.1146/annurev-pharmtox-010919-023420] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The three small-conductance calcium-activated potassium (KCa2) channels and the related intermediate-conductance KCa3.1 channel are voltage-independent K+ channels that mediate calcium-induced membrane hyperpolarization. When intracellular calcium increases in the channel vicinity, it calcifies the flexible N lobe of the channel-bound calmodulin, which then swings over to the S4-S5 linker and opens the channel. KCa2 and KCa3.1 channels are highly druggable and offer multiple binding sites for venom peptides and small-molecule blockers as well as for positive- and negative-gating modulators. In this review, we briefly summarize the physiological role of KCa channels and then discuss the pharmacophores and the mechanism of action of the most commonly used peptidic and small-molecule KCa2 and KCa3.1 modulators. Finally, we describe the progress that has been made in advancing KCa3.1 blockers and KCa2.2 negative- and positive-gating modulators toward the clinic for neurological and cardiovascular diseases and discuss the remaining challenges.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology, University of California, Davis, California 95616, USA;
| | - Heesung Shim
- Department of Pharmacology, University of California, Davis, California 95616, USA;
| | | | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California 95616, USA;
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14
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Critical regulation of atherosclerosis by the KCa3.1 channel and the retargeting of this therapeutic target in in-stent neoatherosclerosis. J Mol Med (Berl) 2019; 97:1219-1229. [DOI: 10.1007/s00109-019-01814-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 05/07/2019] [Accepted: 06/18/2019] [Indexed: 01/09/2023]
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15
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Valero MS, Ramón-Gimenez M, Lozano-Gerona J, Delgado-Wicke P, Calmarza P, Oliván-Viguera A, López V, Garcia-Otín ÁL, Valero S, Pueyo E, Hamilton KL, Miura H, Köhler R. KCa3.1 Transgene Induction in Murine Intestinal Epithelium Causes Duodenal Chyme Accumulation and Impairs Duodenal Contractility. Int J Mol Sci 2019; 20:ijms20051193. [PMID: 30857243 PMCID: PMC6429421 DOI: 10.3390/ijms20051193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 12/12/2022] Open
Abstract
The epithelial intermediate-conductance calcium/calmodulin-regulated KCa3.1 channel is considered to be a regulator of intestine function by controlling chloride secretion and water/salt balance. Yet, little is known about the functional importance of KCa3.1 in the intestinal epithelium in vivo. Our objective was to determine the impact of epithelial-specific inducible overexpression of a KCa3.1 transgene (KCa3.1+) and of inducible suppression (KCa3.1−) on intestinal homeostasis and function in mice. KCa3.1 overexpression in the duodenal epithelium of doxycycline (DOX)-treated KCa3.1+ mice was 40-fold above the control levels. Overexpression caused an inflated duodenum and doubling of the chyme content. Histology showed conserved architecture of crypts, villi, and smooth muscle. Unaltered proliferating cell nuclear antigen (PCNA) immune reactivity and reduced amounts of terminal deoxynucleotide transferase mediated X-dUTP nick end labeling (TUNEL)-positive apoptotic cells in villi indicated lower epithelial turnover. Myography showed a reduction in the frequency of spontaneous propulsive muscle contractions with no change in amplitude. The amount of stool in the colon was increased and the frequency of colonic contractions was reduced in KCa3.1+ animals. Senicapoc treatment prevented the phenotype. Suppression of KCa3.1 in DOX-treated KCa3.1− mice caused no overt intestinal phenotype. In conclusion, inducible KCa3.1 overexpression alters intestinal functions by increasing the chyme content and reducing spontaneous contractions and epithelial apoptosis. Induction of epithelial KCa3.1 can play a mechanistic role in the process of adaptation of the intestine.
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Affiliation(s)
- Marta Sofía Valero
- Department of Pharmacology and Physiology, Universidad Zaragoza, 22002 Huesca, Spain.
- Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain.
| | | | - Javier Lozano-Gerona
- Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain.
- BESICoS group, Aragón Institute of Engineering Research, IIS-Aragón, University of Zaragoza, Zaragoza, Spain.
| | - Pablo Delgado-Wicke
- Department of Biology, Universidad Autónoma de Madrid (UAM), 28049 Madrid, Spain .
| | - Pilar Calmarza
- Clinical Biochemistry Service, Miguel Servet University, 50009 Zaragoza, Spain.
| | - Aida Oliván-Viguera
- BESICoS group, Aragón Institute of Engineering Research, IIS-Aragón, University of Zaragoza, Zaragoza, Spain.
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicina (CIBER-BBN), 50018 Zaragoza, Spain.
| | - Víctor López
- Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain.
- Universidad San Jorge, 50830, Villanueva de Gállego, Spain.
| | - Ángel-Luis Garcia-Otín
- Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain.
- BESICoS group, Aragón Institute of Engineering Research, IIS-Aragón, University of Zaragoza, Zaragoza, Spain.
| | | | - Esther Pueyo
- BESICoS group, Aragón Institute of Engineering Research, IIS-Aragón, University of Zaragoza, Zaragoza, Spain.
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicina (CIBER-BBN), 50018 Zaragoza, Spain.
| | - Kirk L Hamilton
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand.
| | - Hiroto Miura
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
| | - Ralf Köhler
- Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain.
- BESICoS group, Aragón Institute of Engineering Research, IIS-Aragón, University of Zaragoza, Zaragoza, Spain.
- Aragón Agency for Research and Development (ARAID), 50009 Zaragoza, Spain.
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Identification of Clotrimazole Derivatives as Specific Inhibitors of Arenavirus Fusion. J Virol 2019; 93:JVI.01744-18. [PMID: 30626681 DOI: 10.1128/jvi.01744-18] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/21/2018] [Indexed: 02/06/2023] Open
Abstract
Arenaviruses are a large family of emerging enveloped negative-strand RNA viruses that include several causative agents of viral hemorrhagic fevers. For cell entry, human-pathogenic arenaviruses use different cellular receptors and endocytic pathways that converge at the level of acidified late endosomes, where the viral envelope glycoprotein mediates membrane fusion. Inhibitors of arenavirus entry hold promise for therapeutic antiviral intervention and the identification of "druggable" targets is of high priority. Using a recombinant vesicular stomatitis virus pseudotype platform, we identified the clotrimazole-derivative TRAM-34, a highly selective antagonist of the calcium-activated potassium channel KCa3.1, as a specific entry inhibitor for arenaviruses. TRAM-34 specifically blocked entry of most arenaviruses, including hemorrhagic fever viruses, but not Lassa virus and other enveloped viruses. Anti-arenaviral activity was likewise observed with the parental compound clotrimazole and the derivative senicapoc, whereas structurally unrelated KCa3.1 inhibitors showed no antiviral effect. Deletion of KCa3.1 by CRISPR/Cas9 technology did not affect the antiarenaviral effect of TRAM-34, indicating that the observed antiviral effect of clotrimazoles was independent of the known pharmacological target. The drug affected neither virus-cell attachment, nor endocytosis, suggesting an effect on later entry steps. Employing a quantitative cell-cell fusion assay that bypasses endocytosis, we demonstrate that TRAM-34 specifically inhibits arenavirus-mediated membrane fusion. In sum, we uncover a novel antiarenaviral action of clotrimazoles that currently undergo in vivo evaluation in the context of other human diseases. Their favorable in vivo toxicity profiles and stability opens the possibility to repurpose clotrimazole derivatives for therapeutic intervention against human-pathogenic arenaviruses.IMPORTANCE Emerging human-pathogenic arenaviruses are causative agents of severe hemorrhagic fevers with high mortality and represent serious public health problems. The current lack of a licensed vaccine and the limited treatment options makes the development of novel antiarenaviral therapeutics an urgent need. Using a recombinant pseudotype platform, we uncovered that clotrimazole drugs, in particular TRAM-34, specifically inhibit cell entry of a range of arenaviruses, including important emerging human pathogens, with the exception of Lassa virus. The antiviral effect was independent of the known pharmacological drug target and involved inhibition of the unusual membrane fusion mechanism of arenaviruses. TRAM-34 and its derivatives currently undergo evaluation against a number of human diseases and show favorable toxicity profiles and high stability in vivo Our study provides the basis for further evaluation of clotrimazole derivatives as antiviral drug candidates. Their advanced stage of drug development will facilitate repurposing for therapeutic intervention against human-pathogenic arenaviruses.
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Kobayashi K, Kawano K, Yamashita K. A Convenient Synthesis of 2-(Alkyl(or Aryl)sulfanyl)-2H-1,4-benzothiazin-3(4H)-one Derivatives. HETEROCYCLES 2019. [DOI: 10.3987/com-18-s(f)1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Matsui M, Terasawa K, Kajikuri J, Kito H, Endo K, Jaikhan P, Suzuki T, Ohya S. Histone Deacetylases Enhance Ca 2+-Activated K⁺ Channel K Ca3.1 Expression in Murine Inflammatory CD4⁺ T Cells. Int J Mol Sci 2018; 19:ijms19102942. [PMID: 30262728 PMCID: PMC6213394 DOI: 10.3390/ijms19102942] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/19/2018] [Accepted: 09/25/2018] [Indexed: 12/11/2022] Open
Abstract
The up-regulated expression of the Ca2+-activated K+ channel KCa3.1 in inflammatory CD4+ T cells has been implicated in the pathogenesis of inflammatory bowel disease (IBD) through the enhanced production of inflammatory cytokines, such as interferon-γ (IFN-γ). However, the underlying mechanisms have not yet been elucidated. The objective of the present study is to clarify the involvement of histone deacetylases (HDACs) in the up-regulation of KCa3.1 in the CD4+ T cells of IBD model mice. The expression levels of KCa3.1 and its regulators, such as function-modifying molecules and transcription factors, were quantitated using a real-time polymerase chain reaction (PCR) assay, Western blotting, and depolarization responses, which were induced by the selective KCa3.1 blocker TRAM-34 (1 μM) and were measured using a voltage-sensitive fluorescent dye imaging system. The treatment with 1 μM vorinostat, a pan-HDAC inhibitor, for 24 h repressed the transcriptional expression of KCa3.1 in the splenic CD4+ T cells of IBD model mice. Accordingly, TRAM-34-induced depolarization responses were significantly reduced. HDAC2 and HDAC3 were significantly up-regulated in the CD4+ T cells of IBD model mice. The down-regulated expression of KCa3.1 was observed following treatments with the selective inhibitors of HDAC2 and HDAC3. The KCa3.1 K+ channel regulates inflammatory cytokine production in CD4+ T cells, mediating epigenetic modifications by HDAC2 and HDAC3.
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Affiliation(s)
- Miki Matsui
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
| | - Kyoko Terasawa
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Junko Kajikuri
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
| | - Hiroaki Kito
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
| | - Kyoko Endo
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
| | - Pattaporn Jaikhan
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 403-8334, Japan.
| | - Takayoshi Suzuki
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 403-8334, Japan.
| | - Susumu Ohya
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
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19
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Brown BM, Pressley B, Wulff H. KCa3.1 Channel Modulators as Potential Therapeutic Compounds for Glioblastoma. Curr Neuropharmacol 2018; 16:618-626. [PMID: 28676010 PMCID: PMC5997873 DOI: 10.2174/1570159x15666170630164226] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/31/2022] Open
Abstract
Background The intermediate-conductance Ca2+-activated K+ channel KCa3.1 is widely expressed in cells of the immune system such as T- and B-lymphocytes, mast cells, macrophages and microglia, but also found in dedifferentiated vascular smooth muscle cells, fibroblasts and many cancer cells including pancreatic, prostate, leukemia and glioblastoma. In all these cell types KCa3.1 plays an important role in cellular activation, migration and proliferation by regulating membrane potential and Ca2+ signaling. Methods and Results KCa3.1 therefore constitutes an attractive therapeutic target for diseases involving excessive proliferation or activation of one more of these cell types and researchers both in academia and in the pharmaceutical industry have developed several potent and selective small molecule inhibitors of KCa3.1. This article will briefly review the available compounds (TRAM-34, senicapoc, NS6180), their binding sites and mechanisms of action, and then discuss the potential usefulness of these compounds for the treatment of brain tumors based on their brain penetration and their efficacy in reducing microglia activation in animal models of ischemic stroke and Alzheimer’s disease. Conclusion Senicapoc, which has previously been in Phase III clinical trials, would be available for repurposing, and could be used to quickly translate findings made with other KCa3.1 blocking tool compounds into clinical trials.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
| | - Brandon Pressley
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
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20
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Lee CH, MacKinnon R. Activation mechanism of a human SK-calmodulin channel complex elucidated by cryo-EM structures. Science 2018; 360:508-513. [PMID: 29724949 DOI: 10.1126/science.aas9466] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/16/2018] [Indexed: 12/17/2022]
Abstract
Small-conductance Ca2+-activated K+ (SK) channels mediate neuron excitability and are associated with synaptic transmission and plasticity. They also regulate immune responses and the size of blood cells. Activation of SK channels requires calmodulin (CaM), but how CaM binds and opens SK channels has been unclear. Here we report cryo-electron microscopy (cryo-EM) structures of a human SK4-CaM channel complex in closed and activated states at 3.4- and 3.5-angstrom resolution, respectively. Four CaM molecules bind to one channel tetramer. Each lobe of CaM serves a distinct function: The C-lobe binds to the channel constitutively, whereas the N-lobe interacts with the S4-S5 linker in a Ca2+-dependent manner. The S4-S5 linker, which contains two distinct helices, undergoes conformational changes upon CaM binding to open the channel pore. These structures reveal the gating mechanism of SK channels and provide a basis for understanding SK channel pharmacology.
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Affiliation(s)
- Chia-Hsueh Lee
- Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University, Howard Hughes Medical Institute, 1230 York Avenue, New York, NY 10065, USA
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University, Howard Hughes Medical Institute, 1230 York Avenue, New York, NY 10065, USA.
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21
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Shenoy PA, Kuo A, Khan N, Gorham L, Nicholson JR, Corradini L, Vetter I, Smith MT. The Somatostatin Receptor-4 Agonist J-2156 Alleviates Mechanical Hypersensitivity in a Rat Model of Breast Cancer Induced Bone Pain. Front Pharmacol 2018; 9:495. [PMID: 29867498 PMCID: PMC5962878 DOI: 10.3389/fphar.2018.00495] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 04/25/2018] [Indexed: 12/12/2022] Open
Abstract
In the majority of patients with breast cancer in the advanced stages, skeletal metastases are common, which may cause excruciating pain. Currently available drug treatments for relief of breast cancer-induced bone pain (BCIBP) include non-steroidal anti-inflammatory drugs and strong opioid analgesics along with inhibitors of osteoclast activity such as bisphosphonates and monoclonal antibodies such as denosumab. However, these medications often lack efficacy and/or they may produce serious dose-limiting side effects. In the present study, we show that J-2156, a somatostatin receptor type 4 (SST4 receptor) selective agonist, reverses pain-like behaviors in a rat model of BCIBP induced by unilateral intra-tibial injection of Walker 256 breast cancer cells. Following intraperitoneal administration, the ED50 of J-2156 for the relief of mechanical allodynia and mechanical hyperalgesia in the ipsilateral hindpaws was 3.7 and 8.0 mg/kg, respectively. Importantly, the vast majority of somatosensory neurons in the dorsal root ganglia including small diameter C-fibers and medium-large diameter fibers, that play a crucial role in cancer pain hypersensitivities, expressed the SST4 receptor. J-2156 mediated pain relief in BCIBP-rats was confirmed by observations of a reduction in the levels of phosphorylated extracellular signal-regulated kinase (pERK), a protein essential for central sensitization and persistent pain, in the spinal dorsal horn. Our results demonstrate the potential of the SST4 receptor as a pharmacological target for relief of BCIBP and we anticipate the present work to be a starting point for further mechanism-based studies.
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Affiliation(s)
- Priyank A Shenoy
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Andy Kuo
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Nemat Khan
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Louise Gorham
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Janet R Nicholson
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Laura Corradini
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.,Faculty of Health and Behavioural Sciences, School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia
| | - Maree T Smith
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia.,Faculty of Health and Behavioural Sciences, School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia
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22
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Tanner MR, Beeton C. Differences in ion channel phenotype and function between humans and animal models. FRONT BIOSCI-LANDMRK 2018; 23:43-64. [PMID: 28930537 PMCID: PMC5626566 DOI: 10.2741/4581] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ion channels play crucial roles in regulating a broad range of physiological processes. They form a very large family of transmembrane proteins. Their diversity results from not only a large number of different genes encoding for ion channel subunits but also the ability of subunits to assemble into homo- or heteromultimers, the existence of splice variants, and the expression of different regulatory subunits. These characteristics and the existence of very selective modulators make ion channels very attractive targets for therapy in a wide variety of pathologies. Some ion channels are already being targeted in the clinic while many more are being evaluated as novel drug targets in both clinical and preclinical studies. Advancing ion channel modulators from the bench to the clinic requires their assessment for safety and efficacy in animal models. While extrapolating results from one species to another is tempting, doing such without careful evaluation of the ion channels in different species presents a risk as the translation is not always straightforward. Here, we discuss differences between species in terms of ion channels expressed in selected tissues, differing roles of ion channels in some cell types, variable response to pharmacological agents, and human channelopathies that cannot fully be replicated in animal models.
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Affiliation(s)
- Mark R Tanner
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston TX 77030, and Interdepartmental Graduate Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston TX 77030
| | - Christine Beeton
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston TX 77030, and Center for Drug Discovery and Biology of Inflammation Center, Baylor College of Medicine, Houston TX 77030,
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23
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Kobayashi K, Kawano K, Fujiwara D. One-Pot Synthesis of 3-Oxo-2H,4H-1,4-benzothiazine-2-carbonitrile Derivatives via Cyclization of Methyl {[2-(Cyanomethyl)sulfanyl]phenyl}carbamate. HETEROCYCLES 2018. [DOI: 10.3987/com-18-13966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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24
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Brown BM, Shim H, Zhang M, Yarov-Yarovoy V, Wulff H. Structural Determinants for the Selectivity of the Positive KCa3.1 Gating Modulator 5-Methylnaphtho[2,1- d]oxazol-2-amine (SKA-121). Mol Pharmacol 2017; 92:469-480. [PMID: 28760780 DOI: 10.1124/mol.117.109421] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/27/2017] [Indexed: 12/20/2022] Open
Abstract
Intermediate-conductance (KCa3.1) and small-conductance (KCa2) calcium-activated K+ channels are gated by calcium binding to calmodulin (CaM) molecules associated with the calmodulin-binding domain (CaM-BD) of these channels. The existing KCa activators, such as naphtho[1,2-d]thiazol-2-ylamine (SKA-31), 6,7-dichloro-1H-indole-2,3-dione 3-oxime (NS309), and 1-ethylbenzimidazolin-2-one (EBIO), activate both channel types with similar potencies. In a previous chemistry effort, we optimized the benzothiazole pharmacophore of SKA-31 toward KCa3.1 selectivity and identified 5-methylnaphtho[2,1-d]oxazol-2-amine (SKA-121), which exhibits 40-fold selectivity for KCa3.1 over KCa2.3. To understand why introduction of a single CH3 group in five-position of the benzothiazole/oxazole system could achieve such a gain in selectivity for KCa3.1 over KCa2.3, we first localized the binding site of the benzothiazoles/oxazoles to the CaM-BD/CaM interface and then used computational modeling software to generate models of the KCa3.1 and KCa2.3 CaM-BD/CaM complexes with SKA-121. Based on a combination of mutagenesis and structural modeling, we suggest that all benzothiazole/oxazole-type KCa activators bind relatively "deep" in the CaM-BD/CaM interface and hydrogen bond with E54 on CaM. In KCa3.1, SKA-121 forms an additional hydrogen bond network with R362. In contrast, NS309 sits more "forward" and directly hydrogen bonds with R362 in KCa3.1. Mutating R362 to serine, the corresponding residue in KCa2.3 reduces the potency of SKA-121 by 7-fold, suggesting that R362 is responsible for the generally greater potency of KCa activators on KCa3.1. The increase in SKA-121's KCa3.1 selectivity compared with its parent, SKA-31, seems to be due to better overall shape complementarity and hydrophobic interactions with S372 and M368 on KCa3.1 and M72 on CaM at the KCa3.1-CaM-BD/CaM interface.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology (B.M.B., H.S., H.W.), Department of Physiology and Membrane Biology (V.Y.-Y.), School of Medicine, and Department of Chemistry (H.S.), University of California, Davis, California; and Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (M.Z.)
| | - Heesung Shim
- Department of Pharmacology (B.M.B., H.S., H.W.), Department of Physiology and Membrane Biology (V.Y.-Y.), School of Medicine, and Department of Chemistry (H.S.), University of California, Davis, California; and Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (M.Z.)
| | - Miao Zhang
- Department of Pharmacology (B.M.B., H.S., H.W.), Department of Physiology and Membrane Biology (V.Y.-Y.), School of Medicine, and Department of Chemistry (H.S.), University of California, Davis, California; and Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (M.Z.)
| | - Vladimir Yarov-Yarovoy
- Department of Pharmacology (B.M.B., H.S., H.W.), Department of Physiology and Membrane Biology (V.Y.-Y.), School of Medicine, and Department of Chemistry (H.S.), University of California, Davis, California; and Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (M.Z.)
| | - Heike Wulff
- Department of Pharmacology (B.M.B., H.S., H.W.), Department of Physiology and Membrane Biology (V.Y.-Y.), School of Medicine, and Department of Chemistry (H.S.), University of California, Davis, California; and Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (M.Z.)
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Műzes G, Kiss AL, Tulassay Z, Sipos F. Cell-free DNA-induced alteration of autophagy response and TLR9-signaling: Their relation to amelioration of DSS-colitis. Comp Immunol Microbiol Infect Dis 2017; 52:48-57. [PMID: 28673462 DOI: 10.1016/j.cimid.2017.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/21/2017] [Accepted: 06/04/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND The influence of cell-free DNA (fDNA) administration on the TLR9-autophagy regulatory crosstalk within inflammatory circumstances remains unclear. AIMS To examine the immunobiologic effects of iv. fDNA injection on the TLR9-mediated autophagy response in murine DSS-colitis. METHODS Different types of modified fDNAs were administered to DSS-colitic mice. Disease and histological activities, spleen index were measured. Changes of the TLR9-associated and autophagy-related gene expression profiles of lamina proprial cells and splenocytes were assayed by quantitative real-time PCR, and validated by immunohistochemistries. Ultrastructural changes of the colon were examined by transmission electron microscopy (TEM). RESULTS A single intravenous injection of colitic fDNA (C-DNA) exhibited beneficial clinical and histological effects on DSS-colitis, compared to normal (N-DNA). C-DNA administration displayed a more prominent impact on the outcome of the TLR9-autophagy response than N-DNA. C-DNA resulted in a decreased spleen index in DSS-colitic mice. C-DNA treatment of normal mice resulted in a downregulation of Beclin1 and ATG16L1 mRNA and protein expression in the colon. These as well as LC3B were downregulated in the spleen. In contrast, the Beclin1, ATG16L1 and LC3B gene and protein expressions were upregulated in both the colon and the spleen by C-DNA injection. Moreover, C-DNA administration to DSS-colitic mice resulted in a remarkable increase of epithelial autophagic vacuoles representing an intensified macroautophagy. CONCLUSIONS The effect of intravenously administered fDNA on the TLR9-mediated autophagy response is expressly dependent on the origin of fDNA (i.e. inflammatory or not) and on the characteristics of the local immunobiologic milieu (i.e. inflammatory or not, as well).
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Affiliation(s)
- Györgyi Műzes
- 2nd Department of Internal Medicine, Semmelweis University, 1088 Budapest, Hungary.
| | - Anna L Kiss
- Department of Human Morphology and Developmental Biology, Semmelweis University, 1094 Budapest, Hungary
| | - Zsolt Tulassay
- 2nd Department of Internal Medicine, Semmelweis University, 1088 Budapest, Hungary; Molecular Medicine Research Unit, Hungarian Academy of Sciences, Budapest, 1051, Hungary
| | - Ferenc Sipos
- 2nd Department of Internal Medicine, Semmelweis University, 1088 Budapest, Hungary
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26
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Nguyen HM, Singh V, Pressly B, Jenkins DP, Wulff H, Yarov-Yarovoy V. Structural Insights into the Atomistic Mechanisms of Action of Small Molecule Inhibitors Targeting the KCa3.1 Channel Pore. Mol Pharmacol 2017; 91:392-402. [PMID: 28126850 PMCID: PMC5363711 DOI: 10.1124/mol.116.108068] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 01/19/2017] [Indexed: 12/13/2022] Open
Abstract
The intermediate-conductance Ca2+-activated K+ channel (KCa3.1) constitutes an attractive pharmacological target for immunosuppression, fibroproliferative disorders, atherosclerosis, and stroke. However, there currently is no available crystal structure of this medically relevant channel that could be used for structure-assisted drug design. Using the Rosetta molecular modeling suite we generated a molecular model of the KCa3.1 pore and tested the model by first confirming previously mapped binding sites and visualizing the mechanism of TRAM-34 (1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole), senicapoc (2,2-bis-(4-fluorophenyl)-2-phenylacetamide), and NS6180 (4-[[3-(trifluoromethyl)phenyl]methyl]-2H-1,4-benzothiazin-3(4H)-one) inhibition at the atomistic level. All three compounds block ion conduction directly by fully or partially occupying the site that would normally be occupied by K+ before it enters the selectivity filter. We then challenged the model to predict the receptor sites and mechanisms of action of the dihydropyridine nifedipine and an isosteric 4-phenyl-pyran. Rosetta predicted receptor sites for nifedipine in the fenestration region and for the 4-phenyl-pyran in the pore lumen, which could both be confirmed by site-directed mutagenesis and electrophysiology. While nifedipine is thus not a pore blocker and might be stabilizing the channel in a nonconducting conformation or interfere with gating, the 4-phenyl-pyran was found to be a classical pore blocker that directly inhibits ion conduction similar to the triarylmethanes TRAM-34 and senicapoc. The Rosetta KCa3.1 pore model explains the mechanism of action of several KCa3.1 blockers at the molecular level and could be used for structure-assisted drug design.
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Affiliation(s)
- Hai M Nguyen
- Department of Pharmacology (H.M.N, V.S., B.P., D.P.J., H.W.) and Department of Physiology and Membrane Biology (V. Y.-Y.), School of Medicine, University of California at Davis, Davis, California
| | - Vikrant Singh
- Department of Pharmacology (H.M.N, V.S., B.P., D.P.J., H.W.) and Department of Physiology and Membrane Biology (V. Y.-Y.), School of Medicine, University of California at Davis, Davis, California
| | - Brandon Pressly
- Department of Pharmacology (H.M.N, V.S., B.P., D.P.J., H.W.) and Department of Physiology and Membrane Biology (V. Y.-Y.), School of Medicine, University of California at Davis, Davis, California
| | - David Paul Jenkins
- Department of Pharmacology (H.M.N, V.S., B.P., D.P.J., H.W.) and Department of Physiology and Membrane Biology (V. Y.-Y.), School of Medicine, University of California at Davis, Davis, California
| | - Heike Wulff
- Department of Pharmacology (H.M.N, V.S., B.P., D.P.J., H.W.) and Department of Physiology and Membrane Biology (V. Y.-Y.), School of Medicine, University of California at Davis, Davis, California
| | - Vladimir Yarov-Yarovoy
- Department of Pharmacology (H.M.N, V.S., B.P., D.P.J., H.W.) and Department of Physiology and Membrane Biology (V. Y.-Y.), School of Medicine, University of California at Davis, Davis, California
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Staal RGW, Weinstein JR, Nattini M, Cajina M, Chandresana G, Möller T. Senicapoc: Repurposing a Drug to Target Microglia K Ca3.1 in Stroke. Neurochem Res 2017; 42:2639-2645. [PMID: 28364331 DOI: 10.1007/s11064-017-2223-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 12/14/2022]
Abstract
Stroke is the leading cause of serious long-term disability and the fifth leading cause of death in the United States. Treatment options for stroke are few in number and limited in efficacy. Neuroinflammation mediated by microglia and infiltrating peripheral immune cells is a major component of stroke pathophysiology. Interfering with the inflammation cascade after stroke holds the promise to modulate stroke outcome. The calcium activated potassium channel KCa3.1 is expressed selectively in the injured CNS by microglia. KCa3.1 function has been implicated in pro-inflammatory activation of microglia and there is recent literature suggesting that this channel is important in the pathophysiology of ischemia/reperfusion (stroke) related brain injury. Here we describe the potential of repurposing Senicapoc, a KCa3.1 inhibitor, to intervene in the inflammation cascade that follows ischemia/reperfusion.
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Affiliation(s)
- Roland G W Staal
- Alentis Pharma LLC, 72 Hillside Avenue, Metuchen, NJ, 08840, USA
| | - Jonathan R Weinstein
- Department of Neurology, School of Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Megan Nattini
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ, 07652, USA
| | - Manuel Cajina
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ, 07652, USA
| | - Gamini Chandresana
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ, 07652, USA
| | - Thomas Möller
- Abbvie, Foundational Neuroscience Center, Cambridge, MA, 02139, USA.
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28
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Nguyen HM, Blomster LV, Christophersen P, Wulff H. Potassium channel expression and function in microglia: Plasticity and possible species variations. Channels (Austin) 2017; 11:305-315. [PMID: 28277939 DOI: 10.1080/19336950.2017.1300738] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Potassium channels play important roles in microglia functions and thus constitute potential targets for the treatment of neurodegenerative diseases like Alzheimer, Parkinson and stroke. However, uncertainty still prevails as to which potassium channels are expressed and at what levels in different species, how the expression pattern changes upon activation with M1 or M2 polarizing stimuli compared with more complex exposure paradigms, and - most importantly - how these findings relate to the in vivo situation. In this mini-review we discuss the functional potassium channel expression pattern in cultured neonatal mouse microglia in the light of data obtained previously from animal disease models and immunohistochemical studies and compare it with a recent study of adult human microglia isolated from epilepsy patients. Overall, microglial potassium channel expression is very plastic and possibly shows species differences and therefore should be studied carefully in each disease setting and respective animal models.
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Affiliation(s)
- Hai M Nguyen
- a Department of Pharmacology , University of California , Davis, Davis , CA , USA
| | | | | | - Heike Wulff
- a Department of Pharmacology , University of California , Davis, Davis , CA , USA
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29
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Rivolta I, Binda A, Molteni L, Rizzi L, Bresciani E, Possenti R, Fehrentz JA, Verdié P, Martinez J, Omeljaniuk RJ, Locatelli V, Torsello A. JMV5656, A Novel Derivative of TLQP-21, Triggers the Activation of a Calcium-Dependent Potassium Outward Current in Microglial Cells. Front Cell Neurosci 2017; 11:41. [PMID: 28280458 PMCID: PMC5322282 DOI: 10.3389/fncel.2017.00041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 02/08/2017] [Indexed: 01/13/2023] Open
Abstract
TLQP-21 (TLQPPASSRRRHFHHALPPAR) is a multifunctional peptide that is involved in the control of physiological functions, including feeding, reproduction, stress responsiveness, and general homeostasis. Despite the huge interest in TLQP-21 biological activity, very little is known about its intracellular mechanisms of action. In microglial cells, TLQP-21 stimulates increases of intracellular Ca2+ that may activate functions, including proliferation, migration, phagocytosis and production of inflammatory molecules. Our aim was to investigate whether JMV5656 (RRRHFHHALPPAR), a novel short analogue of TLQP-21, stimulates intracellular Ca2+ in the N9 microglia cells, and whether this Ca2+ elevation is coupled with the activation Ca2+-sensitive K+ channels. TLQP-21 and JMV5656 induced a sharp, dose-dependent increment in intracellular calcium. In 77% of cells, JMV5656 also caused an increase in the total outward currents, which was blunted by TEA (tetraethyl ammonium chloride), a non-selective blocker of voltage-dependent and Ca2+-activated potassium (K+) channels. Moreover, the effects of ion channel blockers charybdotoxin and iberiotoxin, suggested that multiple calcium-activated K+ channel types drove the outward current stimulated by JMV5656. Additionally, inhibition of JMV5656-stimulated outward currents by NS6180 (4-[[3-(trifluoromethyl)phenyl]methyl]-2H-1,4 benzothiazin-3(4H)-one) and TRAM-34 (triarylmethane-34), indicated that KCa3.1 channels are involved in this JMV5656 mechanisms of action. In summary, we demonstrate that, in N9 microglia cells, the interaction of JMV5656 with the TLQP-21 receptors induced an increase in intracellular Ca2+, and, following extracellular Ca2+ entry, the opening of KCa3.1 channels.
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Affiliation(s)
- Ilaria Rivolta
- Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy
| | - Anna Binda
- Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy
| | - Laura Molteni
- Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy
| | - Laura Rizzi
- Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy
| | - Elena Bresciani
- Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy
| | - Roberta Possenti
- Department of Medicine of Systems, University of Rome "Tor Vergata" Rome, Italy
| | - Jean-Alain Fehrentz
- CNRS, Institut des Biomolécules Max Mousseron UMR5247, École Nationale Supérieure de Chimie de Montpellier - University of Montpellier Montpellier, France
| | - Pascal Verdié
- CNRS, Institut des Biomolécules Max Mousseron UMR5247, École Nationale Supérieure de Chimie de Montpellier - University of Montpellier Montpellier, France
| | - Jean Martinez
- CNRS, Institut des Biomolécules Max Mousseron UMR5247, École Nationale Supérieure de Chimie de Montpellier - University of Montpellier Montpellier, France
| | | | - Vittorio Locatelli
- Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy
| | - Antonio Torsello
- Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy
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Khalili H, Malik S, Ananthakrishnan AN, Garber JJ, Higuchi LM, Joshi A, Peloquin J, Richter JM, Stewart KO, Curhan GC, Awasthi A, Yajnik V, Chan AT. Identification and Characterization of a Novel Association between Dietary Potassium and Risk of Crohn's Disease and Ulcerative Colitis. Front Immunol 2016; 7:554. [PMID: 28003811 PMCID: PMC5141241 DOI: 10.3389/fimmu.2016.00554] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 11/18/2016] [Indexed: 12/19/2022] Open
Abstract
Background Recent animal studies have identified that dietary salt intake may modify the risk and progression of autoimmune disorders through modulation of the IL-23/TH17 pathway, which is critical in the pathogenesis of ulcerative colitis (UC) and Crohn’s disease (CD). Methods We conducted a prospective study of U.S. women enrolled in the Nurses’ Health Study (NHS) and NHSII who provided detailed and validated information on diet and lifestyle beginning in 1984 in NHS and 1991 in NHSII. We confirmed incident cases of UC and CD reported through 2010 in NHS and 2011 in NHSII. We used Cox proportional hazards models to calculate hazard ratios and 95% confidence intervals. In a case–control study nested within these cohorts, we evaluated the interaction between single nucleotide polymorphisms (SNPs) in genes involved in TH17 pathway and dietary potassium on risk of CD and UC. In a cohort of healthy volunteers, we also assessed the effect of supplemental potassium on development of naïve and memory T cells, differentiated with TGFβ1 or TH17 conditions. Results Among a total of 194,711 women over a follow-up of 3,220,247 person-years, we documented 273 cases of CD and 335 cases of UC. Dietary intake of potassium (Ptrend = 0.005) but not sodium (Ptrend = 0.44) was inversely associated with risk of CD. Although, both dietary potassium and sodium were not significantly associated with risk of UC, there was a suggestion of an inverse association with dietary potassium (Ptrend = 0.08). The association of potassium with risk of CD and UC appeared to be modified by loci involved in the TH17 pathway that have previously been associated with susceptibility to CD, particularly SNP rs7657746 (IL21) (Pinteraction = 0.004 and 0.01, respectively). In vitro, potassium enhanced the expression of Foxp3 in both naïve and memory CD4+ T cells via activating Smad2/3 and inhibiting Smad7 in TH17 cells. Conclusion Dietary potassium is inversely associated with risk of CD with both in vitro and gene–environment interaction data suggesting a potential role for potassium in regulating immune tolerance through its effect on Tregs and TH17 pathway.
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Affiliation(s)
- Hamed Khalili
- Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Clinical and Translational Epidemiology Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Sakshi Malik
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster , Faridabad , India
| | - Ashwin N Ananthakrishnan
- Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Clinical and Translational Epidemiology Unit, Massachusetts General Hospital, Boston, MA, USA
| | - John J Garber
- Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School , Boston, MA , USA
| | - Leslie M Higuchi
- Division of Gastroenterology and Nutrition, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
| | - Amit Joshi
- Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Clinical and Translational Epidemiology Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Joanna Peloquin
- Division of Gastroenterology and Hepatology, Johns Hopkins School of Medicine , Baltimore, MD , USA
| | - James M Richter
- Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School , Boston, MA , USA
| | - Kathleen O Stewart
- Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School , Boston, MA , USA
| | - Gary C Curhan
- Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA
| | - Amit Awasthi
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster , Faridabad , India
| | - Vijay Yajnik
- Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School , Boston, MA , USA
| | - Andrew T Chan
- Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Clinical and Translational Epidemiology Unit, Massachusetts General Hospital, Boston, MA, USA; Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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KCa3.1 (IK) modulates pancreatic cancer cell migration, invasion and proliferation: anomalous effects on TRAM-34. Pflugers Arch 2016; 468:1865-1875. [DOI: 10.1007/s00424-016-1891-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/05/2016] [Accepted: 10/06/2016] [Indexed: 12/30/2022]
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32
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Blomster LV, Strøbaek D, Hougaard C, Klein J, Pinborg LH, Mikkelsen JD, Christophersen P. Quantification of the functional expression of the Ca 2+ -activated K + channel K Ca 3.1 on microglia from adult human neocortical tissue. Glia 2016; 64:2065-2078. [PMID: 27470924 DOI: 10.1002/glia.23040] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 07/11/2016] [Indexed: 12/11/2022]
Abstract
The KCa 3.1 channel (KCNN4) is an important modulator of microglia responses in rodents, but no information exists on functional expression on microglia from human adults. We isolated and cultured microglia (max 1% astrocytes, no neurons or oligodendrocytes) from neocortex surgically removed from epilepsy patients and employed electrophysiological whole-cell measurements and selective pharmacological tools to elucidate functional expression of KCa 3.1. The channel expression was demonstrated as a significant increase in the voltage-independent current by NS309, a KCa 3.1/KCa 2 activator, followed by full inhibition upon co-application with NS6180, a highly selective KCa 3.1 inhibitor. A major fraction (79%) of unstimulated human microglia expressed KCa 3.1, and the difference in current between full activation and inhibition (ΔKCa 3.1) was estimated at 292 ± 48 pA at -40 mV (n = 75), which equals at least 585 channels per cell. Serial KCa 3.1 activation/inhibition significantly hyperpolarized/depolarized the membrane potential. The isolated human microglia were potently activated by lipopolysaccharide (LPS) shown as a prominent increase in TNF-α production. However, incubation with LPS neither changed the KCa 3.1 current nor the fraction of KCa 3.1 expressing cells. In contrast, the anti-inflammatory cytokine IL-4 slightly increased the KCa 3.1 current per cell, but as the membrane area also increased, there was no significant change in channel density. A large fraction of the microglia also expressed a voltage-dependent current sensitive to the KCa 1.1 modulators NS1619 and Paxilline and an inward-rectifying current with the characteristics of a Kir channel. The high functional expression of KCa 3.1 in microglia from epilepsy patients accentuates the need for further investigations of its role in neuropathological processes. GLIA 2016;64:2065-2078.
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Affiliation(s)
- Linda V Blomster
- Saniona A/S, Baltorpvej 154, 2750, Ballerup, Denmark.,Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | | | | | - Jessica Klein
- Saniona A/S, Baltorpvej 154, 2750, Ballerup, Denmark
| | - Lars H Pinborg
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Epilepsy Clinic, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jens D Mikkelsen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
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Modafinil improves monocrotaline-induced pulmonary hypertension rat model. Pediatr Res 2016; 80:119-27. [PMID: 26959484 DOI: 10.1038/pr.2016.38] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/16/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND Pulmonary arterial hypertension (PAH) progressively leads to increases in pulmonary vasoconstriction. Modafinil plays a role in vasorelaxation and blocking KCa3.1 channel with a result of elevating intracellular cyclic adenosine monophosphate (cAMP) levels. The purpose of this study is to evaluate the effects on modafinil in monocrotaline (MCT)-induced PAH rat. METHODS The rats were separated into three groups: the control group, the monocrotaline (M) group (MCT 60 mg/kg), and the modafinil (MD) group (MCT 60 mg/kg + modafinil). RESULTS Reduced right ventricular pressure (RVP) was observed in the MD group. Right ventricular hypertrophy was improved in the MD group. Reduced number of intra-acinar pulmonary arteries and medial wall thickness were noted in the MD group. After the administration of modafinil, protein expressions of endothelin-1 (ET-1), endothelin receptor A (ERA) and KCa3.1 channel were significantly reduced. Modafinil suppressed pulmonary artery smooth muscle cell (PASMC) proliferation via cAMP and KCa3.1 channel. Additionally, we confirmed protein expressions such as Bcl-2-associated X, vascular endothelial growth factor, tumor necrosis factor-α, and interleukin-6 were reduced in the MD group. CONCLUSION Modafinil improved PAH by vasorelaxation and a decrease in medial thickening via ET-1, ERA, and KCa3.1 down regulation. This is a meaningful study of a modafinil in PAH model.
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35
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Magalhães D, Cabral JM, Soares-da-Silva P, Magro F. Role of epithelial ion transports in inflammatory bowel disease. Am J Physiol Gastrointest Liver Physiol 2016; 310:G460-76. [PMID: 26744474 DOI: 10.1152/ajpgi.00369.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/02/2016] [Indexed: 02/06/2023]
Abstract
Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with a complex pathogenesis. Diarrhea is a highly prevalent and often debilitating symptom of IBD patients that results, at least in part, from an intestinal hydroelectrolytic imbalance. Evidence suggests that reduced electrolyte absorption is more relevant than increased secretion to this disequilibrium. This systematic review analyses and integrates the current evidence on the roles of epithelial Na(+)-K(+)-ATPase (NKA), Na(+)/H(+) exchangers (NHEs), epithelial Na(+) channels (ENaC), and K(+) channels (KC) in IBD-associated diarrhea. NKA is the key driving force of the transepithelial ionic transport and its activity is decreased in IBD. In addition, the downregulation of apical NHE and ENaC and the upregulation of apical large-conductance KC all contribute to the IBD-associated diarrhea by lowering sodium absorption and/or increasing potassium secretion.
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Affiliation(s)
- Diogo Magalhães
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - José Miguel Cabral
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Patrício Soares-da-Silva
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Fernando Magro
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
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36
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Turner RW, Asmara H, Engbers JDT, Miclat J, Rizwan AP, Sahu G, Zamponi GW. Assessing the role of IKCa channels in generating the sAHP of CA1 hippocampal pyramidal cells. Channels (Austin) 2016; 10:313-9. [PMID: 26950800 PMCID: PMC4954577 DOI: 10.1080/19336950.2016.1161988] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Our previous work reported that KCa3.1 (IKCa) channels are expressed in CA1 hippocampal pyramidal cells and contribute to the slow afterhyperpolarization that regulates spike accommodation in these cells. The current report presents data from single cell RT-PCR that further reveals mRNA in CA1 cells that corresponds to the sequence of an IKCa channel from transmembrane segments 5 through 6 including the pore region, revealing the established binding sites for 4 different IKCa channel blockers. A comparison of methods to internally apply the IKCa channel blocker TRAM-34 shows that including the drug in an electrode from the onset of an experiment is unviable given the speed of drug action upon gaining access for whole-cell recordings. Together the data firmly establish IKCa channel expression in CA1 neurons and clarify methodological requirements to obtain a block of IKCa channel activity through internal application of TRAM-34.
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Affiliation(s)
- Ray W Turner
- a Hotchkiss Brain Institute, University of Calgary , Calgary , AB , Canada
| | - Hadhimulya Asmara
- a Hotchkiss Brain Institute, University of Calgary , Calgary , AB , Canada
| | - Jordan D T Engbers
- a Hotchkiss Brain Institute, University of Calgary , Calgary , AB , Canada
| | - Jason Miclat
- a Hotchkiss Brain Institute, University of Calgary , Calgary , AB , Canada
| | - Arsalan P Rizwan
- a Hotchkiss Brain Institute, University of Calgary , Calgary , AB , Canada
| | - Giriraj Sahu
- a Hotchkiss Brain Institute, University of Calgary , Calgary , AB , Canada
| | - Gerald W Zamponi
- a Hotchkiss Brain Institute, University of Calgary , Calgary , AB , Canada
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Abstract
Potassium ion (K(+)) channels play an important role in the modulation of calcium ion (Ca(2+)) signaling via control of the membrane potential. In T-lymphocytes, the voltage-gated K(+) channel, KV1.3, and the intermediate-conductance Ca(2+)-activated K(+) channel, KCa3.1, predominantly contribute to K(+) conductance, and are responsible for cell proliferation, differentiation, apoptosis and infiltration. Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, afflicts more than 0.1% of the population worldwide. In the chemically-induced IBD model mouse, an increase in KCa3.1 activity was observed in mesenteric lymph node CD4(+) T-lymphocytes, concomitant with an upregulation of KCa3.1 and a positive KCa3.1 regulator, NDPK-B. Pharmacological blockade of the KCa3.1 K(+) channel by TRAM-34 and/or ICA17043 elicited 1) a significant decrease in IBD severity, as assessed by diarrhea, visible fecal blood, inflammation and crypt damage of the colon; and 2) restoration of the expression levels of KCa3.1 and Th1 cytokines in CD4(+) T-lymphocytes in the IBD model. Recent studies have indicated the impact of K2P5.1 upregulation in T lymphocytes on the pathogenesis of autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. The K2P5.1 K(+) channel is therefore highlighted as a potent therapeutic target in managing the pathogenesis of autoimmune diseases. Alternatively, pre-mRNA splicing of ion channels is associated with the development and progression of various diseases, including autoimmune diseases. Therefore, mRNA-splicing mechanisms underlying the transcriptional regulation of K2P5.1 K(+) channels may be a new strategic therapeutic target for autoimmune and inflammatory diseases.
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Affiliation(s)
- Susumu Ohya
- Department of Pharmacology, Kyoto Pharmaceutical University
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RamaKrishnan AM, Sankaranarayanan K. Understanding autoimmunity: The ion channel perspective. Autoimmun Rev 2016; 15:585-620. [PMID: 26854401 DOI: 10.1016/j.autrev.2016.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 01/29/2016] [Indexed: 12/11/2022]
Abstract
Ion channels are integral membrane proteins that orchestrate the passage of ions across the cell membrane and thus regulate various key physiological processes of the living system. The stringently regulated expression and function of these channels hold a pivotal role in the development and execution of various cellular functions. Malfunction of these channels results in debilitating diseases collectively termed channelopathies. In this review, we highlight the role of these proteins in the immune system with special emphasis on the development of autoimmunity. The role of ion channels in various autoimmune diseases is also listed out. This comprehensive review summarizes the ion channels that could be used as molecular targets in the development of new therapeutics against autoimmune disorders.
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Affiliation(s)
| | - Kavitha Sankaranarayanan
- AU-KBC Research Centre, Madras Institute of Technology, Anna University, Chrompet, Chennai 600 044, India.
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Zundler S, Caioni M, Müller M, Strauch U, Kunst C, Woelfel G. K+ Channel Inhibition Differentially Regulates Migration of Intestinal Epithelial Cells in Inflamed vs. Non-Inflamed Conditions in a PI3K/Akt-Mediated Manner. PLoS One 2016; 11:e0147736. [PMID: 26824610 PMCID: PMC4732808 DOI: 10.1371/journal.pone.0147736] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 01/07/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Potassium channels have been shown to determine wound healing in different tissues, but their role in intestinal epithelial restitution--the rapid closure of superficial wounds by intestinal epithelial cells (IEC)--remains unclear. METHODS In this study, the regulation of IEC migration by potassium channel modulation was explored with and without additional epidermal growth factor (EGF) under baseline and interferon-γ (IFN-γ)-pretreated conditions in scratch assays and Boyden chamber assays using the intestinal epithelial cell lines IEC-18 and HT-29. To identify possibly involved subcellular pathways, Western Blot (WB)-analysis of ERK and Akt phosphorylation was conducted and PI3K and ERK inhibitors were used in scratch assays. Furthermore, mRNA-levels of the potassium channel KCNN4 were determined in IEC from patients suffering from inflammatory bowel diseases (IBD). RESULTS Inhibition of Ca(2+)-dependent potassium channels significantly increased intestinal epithelial restitution, which could not be further promoted by additional EGF. In contrast, inhibition of KCNN4 after pretreatment with IFN-γ led to decreased or unaffected migration. This effect was abolished by EGF. Changes in Akt, but not in ERK phosphorylation strongly correlated with these findings and PI3K but not ERK inhibition abrogated the effect of KCNN4 inhibition. Levels of KCNN4 mRNA were higher in samples from IBD patients compared with controls. CONCLUSIONS Taken together, we demonstrate that inhibition of KCNN4 differentially regulates IEC migration in IFN-γ-pretreated vs. non pretreated conditions. Moreover, our data propose that the PI3K signaling cascade is responsible for this differential regulation. Therefore, we present a cellular model that contributes new aspects to epithelial barrier dysfunction in chronic intestinal inflammation, resulting in propagation of inflammation and symptoms like ulcers or diarrhea.
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Affiliation(s)
- Sebastian Zundler
- Department of Internal Medicine I, Regensburg University Medical Center, Regensburg, Germany
- Department of Medicine 1, University of Erlangen-Nuremberg, Kussmaul Campus for Medical Research & Translational Research Center, Erlangen, Germany
| | - Massimiliano Caioni
- Department of Internal Medicine I, Regensburg University Medical Center, Regensburg, Germany
| | - Martina Müller
- Department of Internal Medicine I, Regensburg University Medical Center, Regensburg, Germany
| | - Ulrike Strauch
- Department of Internal Medicine I, Regensburg University Medical Center, Regensburg, Germany
| | - Claudia Kunst
- Department of Internal Medicine I, Regensburg University Medical Center, Regensburg, Germany
| | - Gisela Woelfel
- Department of Internal Medicine I, Regensburg University Medical Center, Regensburg, Germany
- * E-mail:
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King B, Rizwan AP, Asmara H, Heath NC, Engbers JDT, Dykstra S, Bartoletti TM, Hameed S, Zamponi GW, Turner RW. IKCa channels are a critical determinant of the slow AHP in CA1 pyramidal neurons. Cell Rep 2016; 11:175-82. [PMID: 25865881 DOI: 10.1016/j.celrep.2015.03.026] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/30/2015] [Accepted: 03/10/2015] [Indexed: 12/23/2022] Open
Abstract
Control over the frequency and pattern of neuronal spike discharge depends on Ca2+-gated K+ channels that reduce cell excitability by hyperpolarizing the membrane potential. The Ca2+-dependent slow afterhyperpolarization (sAHP) is one of the most prominent inhibitory responses in the brain, with sAHP amplitude linked to a host of circuit and behavioral functions, yet the channel that underlies the sAHP has defied identification for decades. Here, we show that intermediate-conductance Ca2+-dependent K+ (IKCa) channels underlie the sAHP generated by trains of synaptic input or postsynaptic stimuli in CA1 hippocampal pyramidal cells. These findings are significant in providing a molecular identity for the sAHP of central neurons that will identify pharmacological tools capable of potentially modifying the several behavioral or disease states associated with the sAHP.
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Köhler R, Oliván-Viguera A, Wulff H. Endothelial Small- and Intermediate-Conductance K Channels and Endothelium-Dependent Hyperpolarization as Drug Targets in Cardiovascular Disease. ADVANCES IN PHARMACOLOGY 2016; 77:65-104. [DOI: 10.1016/bs.apha.2016.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
Ion channels and transporters mediate the transport of charged ions across hydrophobic lipid membranes. In immune cells, divalent cations such as calcium, magnesium, and zinc have important roles as second messengers to regulate intracellular signaling pathways. By contrast, monovalent cations such as sodium and potassium mainly regulate the membrane potential, which indirectly controls the influx of calcium and immune cell signaling. Studies investigating human patients with mutations in ion channels and transporters, analysis of gene-targeted mice, or pharmacological experiments with ion channel inhibitors have revealed important roles of ionic signals in lymphocyte development and in innate and adaptive immune responses. We here review the mechanisms underlying the function of ion channels and transporters in lymphocytes and innate immune cells and discuss their roles in lymphocyte development, adaptive and innate immune responses, and autoimmunity, as well as recent efforts to develop pharmacological inhibitors of ion channels for immunomodulatory therapy.
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Affiliation(s)
- Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY 10016
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, California 95616
| | - Edward Y. Skolnik
- Division of Nephrology, New York University School of Medicine, New York, NY 10016
- Department of Molecular Pathogenesis, New York University School of Medicine, New York, NY 10016
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
- The Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016
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43
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Chen YJ, Wallace BK, Yuen N, Jenkins DP, Wulff H, O'Donnell ME. Blood-brain barrier KCa3.1 channels: evidence for a role in brain Na uptake and edema in ischemic stroke. Stroke 2014; 46:237-44. [PMID: 25477223 DOI: 10.1161/strokeaha.114.007445] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE KCa3.1, a calcium-activated potassium channel, regulates ion and fluid secretion in the lung and gastrointestinal tract. It is also expressed on vascular endothelium where it participates in blood pressure regulation. However, the expression and physiological role of KCa3.1 in blood-brain barrier (BBB) endothelium has not been investigated. BBB endothelial cells transport Na(+) and Cl(-) from the blood into the brain transcellularly through the co-operation of multiple cotransporters, exchangers, pumps, and channels. In the early stages of cerebral ischemia, when the BBB is intact, edema formation occurs by processes involving increased BBB transcellular Na(+) transport. This study evaluated whether KCa3.1 is expressed on and participates in BBB ion transport. METHODS The expression of KCa3.1 on cultured cerebral microvascular endothelial cells, isolated microvessels, and brain sections was evaluated by Western blot and immunohistochemistry. Activity of KCa3.1 on cerebral microvascular endothelial cells was examined by K(+) flux assays and patch-clamp. Magnetic resonance spectroscopy and MRI were used to measure brain Na(+) uptake and edema formation in rats with focal ischemic stroke after TRAM-34 treatment. RESULTS KCa3.1 current and channel protein were identified on bovine cerebral microvascular endothelial cells and freshly isolated rat microvessels. In situ KCa3.1 expression on BBB endothelium was confirmed in rat and human brain sections. TRAM-34 treatment significantly reduced Na(+) uptake, and cytotoxic edema in the ischemic brain. CONCLUSIONS BBB endothelial cells exhibit KCa3.1 protein and activity and pharmacological blockade of KCa3.1 seems to provide an effective therapeutic approach for reducing cerebral edema formation in the first 3 hours of ischemic stroke.
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Affiliation(s)
- Yi-Je Chen
- From the Department of Pharmacology (Y.-J.C., D.P.J., H.W.) and Department of Physiology and Membrane Biology (B.K.W., N.Y., M.E.O.), University of California, Davis.
| | - Breanna K Wallace
- From the Department of Pharmacology (Y.-J.C., D.P.J., H.W.) and Department of Physiology and Membrane Biology (B.K.W., N.Y., M.E.O.), University of California, Davis
| | - Natalie Yuen
- From the Department of Pharmacology (Y.-J.C., D.P.J., H.W.) and Department of Physiology and Membrane Biology (B.K.W., N.Y., M.E.O.), University of California, Davis
| | - David P Jenkins
- From the Department of Pharmacology (Y.-J.C., D.P.J., H.W.) and Department of Physiology and Membrane Biology (B.K.W., N.Y., M.E.O.), University of California, Davis
| | - Heike Wulff
- From the Department of Pharmacology (Y.-J.C., D.P.J., H.W.) and Department of Physiology and Membrane Biology (B.K.W., N.Y., M.E.O.), University of California, Davis
| | - Martha E O'Donnell
- From the Department of Pharmacology (Y.-J.C., D.P.J., H.W.) and Department of Physiology and Membrane Biology (B.K.W., N.Y., M.E.O.), University of California, Davis
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44
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Oliván-Viguera A, Valero MS, Coleman N, Brown BM, Laría C, Murillo MD, Gálvez JA, Díaz-de-Villegas MD, Wulff H, Badorrey R, Köhler R. A novel pan-negative-gating modulator of KCa2/3 channels, fluoro-di-benzoate, RA-2, inhibits endothelium-derived hyperpolarization-type relaxation in coronary artery and produces bradycardia in vivo. Mol Pharmacol 2014; 87:338-48. [PMID: 25468883 DOI: 10.1124/mol.114.095745] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Small/intermediate conductance KCa channels (KCa2/3) are Ca(2+)/calmodulin regulated K(+) channels that produce membrane hyperpolarization and shape neurologic, epithelial, cardiovascular, and immunologic functions. Moreover, they emerged as therapeutic targets to treat cardiovascular disease, chronic inflammation, and some cancers. Here, we aimed to generate a new pharmacophore for negative-gating modulation of KCa2/3 channels. We synthesized a series of mono- and dibenzoates and identified three dibenzoates [1,3-phenylenebis(methylene) bis(3-fluoro-4-hydroxybenzoate) (RA-2), 1,2-phenylenebis(methylene) bis(3-fluoro-4-hydroxybenzoate), and 1,4-phenylenebis(methylene) bis(3-fluoro-4-hydroxybenzoate)] with inhibitory efficacy as determined by patch clamp. Among them, RA-2 was the most drug-like and inhibited human KCa3.1 with an IC50 of 17 nM and all three human KCa2 subtypes with similar potencies. RA-2 at 100 nM right-shifted the KCa3.1 concentration-response curve for Ca(2+) activation. The positive-gating modulator naphtho[1,2-d]thiazol-2-ylamine (SKA-31) reversed channel inhibition at nanomolar RA-2 concentrations. RA-2 had no considerable blocking effects on distantly related large-conductance KCa1.1, Kv1.2/1.3, Kv7.4, hERG, or inwardly rectifying K(+) channels. In isometric myography on porcine coronary arteries, RA-2 inhibited bradykinin-induced endothelium-derived hyperpolarization (EDH)-type relaxation in U46619-precontracted rings. Blood pressure telemetry in mice showed that intraperitoneal application of RA-2 (≤100 mg/kg) did not increase blood pressure or cause gross behavioral deficits. However, RA-2 decreased heart rate by ≈145 beats per minute, which was not seen in KCa3.1(-/-) mice. In conclusion, we identified the KCa2/3-negative-gating modulator, RA-2, as a new pharmacophore with nanomolar potency. RA-2 may be of use to generate structurally new types of negative-gating modulators that could help to define the physiologic and pathomechanistic roles of KCa2/3 in the vasculature, central nervous system, and during inflammation in vivo.
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Affiliation(s)
- Aida Oliván-Viguera
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - Marta Sofía Valero
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - Nicole Coleman
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - Brandon M Brown
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - Celia Laría
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - María Divina Murillo
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - José A Gálvez
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - María D Díaz-de-Villegas
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - Heike Wulff
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - Ramón Badorrey
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.)
| | - Ralf Köhler
- Aragon Institute of Health Sciences, Zaragoza, Spain (A.O.-V., R.K.); GIMACES, Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V., C.L.); Department of Pharmacology, School of Medicine, University of California Davis, Davis, California (N.C., B.M.B, H.W.); Departamento de Farmacología y Fisiología, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain (M.D.M.); Departamento de Catálisis y Procesos Catalíticos, Instituto de Síntesis Química y Catálisis Homogénea, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, Zaragoza, Spain (M.D.D.-V., J.A.G., R.B.); and Fundación Agencia Aragonesa para la Investigación y Desarrollo (R.K.).
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Expression of T-cell KV1.3 potassium channel correlates with pro-inflammatory cytokines and disease activity in ulcerative colitis. J Crohns Colitis 2014; 8:1378-91. [PMID: 24793818 PMCID: PMC4216648 DOI: 10.1016/j.crohns.2014.04.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/18/2014] [Accepted: 04/07/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND AND AIMS Potassium channels, KV1.3 and KCa3.1, have been suggested to control T-cell activation, proliferation, and cytokine production and may thus constitute targets for anti-inflammatory therapy. Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by excessive T-cell infiltration and cytokine production. It is unknown if KV1.3 and KCa3.1 in the inflamed mucosa are markers of active UC. We hypothesized that KV1.3 and KCa3.1 correlate with disease activity and cytokine production in patients with UC. METHODS Mucosal biopsies were collected from patients with active UC (n=33) and controls (n=15). Protein and mRNA expression of KV1.3 and KCa3.1, immune cell markers, and pro-inflammatory cytokines were determined by quantitative-real-time-polymerase-chain-reaction (qPCR) and immunofluorescence, and correlated with clinical parameters of inflammation. In-vitro cytokine production was measured in human CD3(+) T-cells after pharmacological blockade of KV1.3 and KCa3.1. RESULTS Active UC KV1.3 mRNA expression was increased 5-fold compared to controls. Immunofluorescence analyses revealed that KV1.3 protein was present in inflamed mucosa in 57% of CD4(+) and 23% of CD8(+) T-cells. KV1.3 was virtually absent on infiltrating macrophages. KV1.3 mRNA expression correlated significantly with mRNA expression of pro-inflammatory cytokines TNF-α (R(2)=0.61) and IL-17A (R(2)=0.51), the mayo endoscopic subscore (R(2)=0.13), and histological inflammation (R(2)=0.23). In-vitro blockade of T-cell KV1.3 and KCa3.1 decreased production of IFN-γ, TNF-α, and IL-17A. CONCLUSIONS High levels of KV1.3 in CD4 and CD8 positive T-cells infiltrates are associated with production of pro-inflammatory IL-17A and TNF-α in active UC. KV1.3 may serve as a marker of disease activity and pharmacological blockade might constitute a novel immunosuppressive strategy.
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Ohya S, Fukuyo Y, Kito H, Shibaoka R, Matsui M, Niguma H, Maeda Y, Yamamura H, Fujii M, Kimura K, Imaizumi Y. Upregulation of KCa3.1 K(+) channel in mesenteric lymph node CD4(+) T lymphocytes from a mouse model of dextran sodium sulfate-induced inflammatory bowel disease. Am J Physiol Gastrointest Liver Physiol 2014; 306:G873-85. [PMID: 24674776 DOI: 10.1152/ajpgi.00156.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The intermediate-conductance Ca(2+)-activated K(+) channel KCa3.1/KCNN4 plays an important role in the modulation of Ca(2+) signaling through the control of the membrane potential in T lymphocytes. Here, we study the involvement of KCa3.1 in the enlargement of the mesenteric lymph nodes (MLNs) in a mouse model of inflammatory bowel disease (IBD). The mouse model of IBD was prepared by exposing male C57BL/6J mice to 5% dextran sulfate sodium for 7 days. Inflammation-induced changes in KCa3.1 activity and the expressions of KCa3.1 and its regulators in MLN CD4(+) T lymphocytes were monitored by real-time PCR, Western blot, voltage-sensitive dye imaging, patch-clamp, and flow cytometric analyses. Concomitant with an upregulation of KCa3.1a and nucleoside diphosphate kinase B (NDPK-B), a positive KCa3.1 regulator, an increase in KCa3.1 activity was observed in MLN CD4(+) T lymphocytes in the IBD model. Pharmacological blockade of KCa3.1 elicited the following results: 1) a significant decrease in IBD disease severity, as assessed by diarrhea, visible fecal blood, inflammation, and crypt damage of the colon and MLN enlargement compared with control mice, and 2) the restoration of the expression levels of KCa3.1a, NDPK-B, and Th1 cytokines in IBD model MLN CD4(+) T lymphocytes. These findings suggest that the increase in KCa3.1 activity induced by the upregulation of KCa3.1a and NDPK-B may be involved in the pathogenesis of IBD by mediating the enhancement of the proliferative response in MLN CD4(+) T lymphocyte and, therefore, that the pharmacological blockade of KCa3.1 may decrease the risk of IBD.
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Affiliation(s)
- Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto, Japan; Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan;
| | - Yuka Fukuyo
- Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan
| | - Hiroaki Kito
- Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan
| | - Rina Shibaoka
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Miki Matsui
- Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan
| | - Hiroki Niguma
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yasuhiro Maeda
- Department of Hospital Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan; and
| | - Hisao Yamamura
- Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan
| | - Masanori Fujii
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Kazunori Kimura
- Department of Hospital Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan; and Department of Clinical Pharmacy, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Yuji Imaizumi
- Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan
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Neuronal expression of the intermediate conductance calcium-activated potassium channel KCa3.1 in the mammalian central nervous system. Pflugers Arch 2014; 467:311-28. [PMID: 24797146 DOI: 10.1007/s00424-014-1523-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 04/14/2014] [Accepted: 04/15/2014] [Indexed: 01/09/2023]
Abstract
The expression pattern and functional roles for calcium-activated potassium channels of the KCa2.x family and KCa1.1 have been extensively examined in central neurons. Recent work indicates that intermediate conductance calcium-activated potassium channels (KCa3.1) are also expressed in central neurons of the cerebellum and spinal cord. The current study used immunocytochemistry and GFP linked to KCNN4 promoter activity in a transgenic mouse to determine the expression pattern of KCa3.1 channels in rat or mouse neocortex, hippocampus, thalamus, and cerebellum. KCa3.1 immunolabel and GFP expression were closely matched and detected in both excitatory and inhibitory cells of all regions examined. KCa3.1 immunolabel was localized primarily to the somatic region of excitatory cells in cortical structures but at the soma and over longer segments of dendrites of cells in deep cerebellar nuclei. More extensive labeling was apparent for inhibitory cells at the somatic and dendritic level with no detectable label associated with axon tracts or regions of intense synaptic innervation. The data indicate that KCa3.1 channels are expressed in the CNS with a differential pattern of distribution between cells, suggesting important functional roles for these calcium-activated potassium channels in regulating the excitability of central neurons.
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The Ca²⁺-activated K⁺ channel KCa3.1 as a potential new target for the prevention of allograft vasculopathy. PLoS One 2013; 8:e81006. [PMID: 24312257 PMCID: PMC3843675 DOI: 10.1371/journal.pone.0081006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 10/09/2013] [Indexed: 12/13/2022] Open
Abstract
Allograft vasculopathy (AV) remains one of the major challenges to the long-term functioning of solid organ transplants. Although its exact pathogenesis remains unclear, AV is characterized by both fibromuscular proliferation and infiltration of CD4+ memory T cells. We here tested whether two experimental immunosuppressants targeting K+ channels might be useful for preventing AV. PAP-1 inhibits the voltage-gated Kv1.3 channel, which is overexpressed on CCR7− memory T cells and we therefore hypothesize that it should suppress the memory T cell component of AV. Based on its previous efficacy in restenosis and kidney fibrosis we expected that the KCa3.1 blocker TRAM-34 would primarily affect smooth muscle and fibroblast proliferation and thus reduce intimal hyperplasia. Using immunohistochemistry we demonstrated the presence of Kv1.3 on infiltrating T cells and of KCa3.1 on lymphocytes as well as on proliferating neointimal smooth muscle cells in human vasculopathy samples and in a rat aorta transplant model developing chronic AV. Treatment of PVG rats receiving orthotopically transplanted aortas from ACI rats with TRAM-34 dose-dependently reduced aortic luminal occlusion, intimal hyperplasia, mononuclear cell infiltration and collagen deposition 120 days after transplantation. The Kv1.3 blocker PAP-1 in contrast did not reduce intima hyperplasia despite drastically reducing plasma IFN-γ levels and inhibiting lymphocyte infiltration. Our findings suggest that KCa3.1 channels play an important role in the pathogenesis of chronic AV and constitute an attractive target for the prevention of arteriopathy.
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Jenkins DP, Yu W, Brown BM, Løjkner LD, Wulff H. Development of a QPatch automated electrophysiology assay for identifying KCa3.1 inhibitors and activators. Assay Drug Dev Technol 2013; 11:551-60. [PMID: 24351043 PMCID: PMC3870577 DOI: 10.1089/adt.2013.543] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The intermediate-conductance Ca(2+)-activated K(+) channel KCa3.1 (also known as KCNN4, IK1, or the Gárdos channel) plays an important role in the activation of T and B cells, mast cells, macrophages, and microglia by regulating membrane potential, cellular volume, and calcium signaling. KCa3.1 is further involved in the proliferation of dedifferentiated vascular smooth muscle cells and fibroblast and endothelium-derived hyperpolarization responses in the vascular endothelium. Accordingly, KCa3.1 inhibitors are therapeutically interesting as immunosuppressants and for the treatment of a wide range of fibroproliferative disorders, whereas KCa3.1 activators constitute a potential new class of endothelial function preserving antihypertensives. Here, we report the development of QPatch assays for both KCa3.1 inhibitors and activators. During assay optimization, the Ca(2+) sensitivity of KCa3.1 was studied using varying intracellular Ca(2+) concentrations. A free Ca(2+) concentration of 1 μM was chosen to optimally test inhibitors. To identify activators, which generally act as positive gating modulators, a lower Ca(2+) concentration (∼200 nM) was used. The QPatch results were benchmarked against manual patch-clamp electrophysiology by determining the potency of several commonly used KCa3.1 inhibitors (TRAM-34, NS6180, ChTX) and activators (EBIO, riluzole, SKA-31). Collectively, our results demonstrate that the QPatch provides a comparable but much faster approach to study compound interactions with KCa3.1 channels in a robust and reliable assay.
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Affiliation(s)
| | - Weifeng Yu
- Sophion Bioscience, Inc., North Brunswick, New Jersey
| | - Brandon M. Brown
- Department of Pharmacology, University of California, Davis, California
| | | | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California
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Koshy S, Wu D, Hu X, Tajhya RB, Huq R, Khan FS, Pennington MW, Wulff H, Yotnda P, Beeton C. Blocking KCa3.1 channels increases tumor cell killing by a subpopulation of human natural killer lymphocytes. PLoS One 2013; 8:e76740. [PMID: 24146918 PMCID: PMC3795664 DOI: 10.1371/journal.pone.0076740] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 08/29/2013] [Indexed: 11/24/2022] Open
Abstract
Natural killer (NK) cells are large granular lymphocytes that participate in both innate and adaptive immune responses against tumors and pathogens. They are also involved in other conditions, including organ rejection, graft-versus-host disease, recurrent spontaneous abortions, and autoimmune diseases such as multiple sclerosis. We demonstrate that human NK cells express the potassium channels Kv1.3 and KCa3.1. Expression of these channels does not vary with expression levels of maturation markers but varies between adherent and non-adherent NK cell subpopulations. Upon activation by mitogens or tumor cells, adherent NK (A-NK) cells preferentially up-regulate KCa3.1 and non-adherent (NA-NK) cells preferentially up-regulate Kv1.3. Consistent with this different phenotype, A-NK and NA-NK do not display the same sensitivity to the selective KCa3.1 blockers TRAM-34 and NS6180 and to the selective Kv1.3 blockers ShK-186 and PAP-1 in functional assays. Kv1.3 block inhibits the proliferation and degranulation of NA-NK cells with minimal effects on A-NK cells. In contrast, blocking KCa3.1 increases the degranulation and cytotoxicity of A-NK cells, but not of NA-NK cells. TRAM-34, however, does not affect their ability to form conjugates with target tumor cells, to migrate, or to express chemokine receptors. TRAM-34 and NS6180 also increase the proliferation of both A-NK and NA-NK cells. This results in a TRAM-34-induced increased ability of A-NK cells to reduce in vivo tumor growth. Taken together, our results suggest that targeting KCa3.1 on NK cells with selective blockers may be beneficial in cancer immunotherapy.
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Affiliation(s)
- Shyny Koshy
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Danli Wu
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas, United States of America
| | - Xueyou Hu
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Rajeev B. Tajhya
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Redwan Huq
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Fatima S. Khan
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | | | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California, United States of America
| | - Patricia Yotnda
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas, United States of America
| | - Christine Beeton
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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