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More NE, Mandlik R, Zine S, Gawali VS, Godad AP. Exploring the therapeutic opportunities of potassium channels for the treatment of rheumatoid arthritis. Front Pharmacol 2024; 15:1286069. [PMID: 38783950 PMCID: PMC11111972 DOI: 10.3389/fphar.2024.1286069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/18/2024] [Indexed: 05/25/2024] Open
Abstract
Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects the synovial joint, which leads to inflammation, loss of function, joint destruction, and disability. The disease biology of RA involves complex interactions between genetic and environmental factors and is strongly associated with various immune cells, and each of the cell types contributes differently to disease pathogenesis. Several immunomodulatory molecules, such as cytokines, are secreted from the immune cells and intervene in the pathogenesis of RA. In immune cells, membrane proteins such as ion channels and transporters mediate the transport of charged ions to regulate intracellular signaling pathways. Ion channels control the membrane potential and effector functions such as cytotoxic activity. Moreover, clinical studies investigating patients with mutations and alterations in ion channels and transporters revealed their importance in effective immune responses. Recent studies have shown that voltage-gated potassium channels and calcium-activated potassium channels and their subtypes are involved in the regulation of immune cells and RA. Due to the role of these channels in the pathogenesis of RA and from multiple pieces of clinical evidence, they can be considered therapeutic targets for the treatment of RA. Here, we describe the role of voltage-gated and calcium-activated potassium channels and their subtypes in RA and their pharmacological application as drug targets.
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Affiliation(s)
| | - Rahul Mandlik
- Medical Affairs, Shalina Healthcare DMCC, Dubai, United Arab Emirates
| | - Sandip Zine
- SVKM’s Dr. Bhanuben Nanavati College of Pharmacy, Mumbai, India
| | | | - Angel Pavalu Godad
- SVKM’s Dr. Bhanuben Nanavati College of Pharmacy, Mumbai, India
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Mumbai, India
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2
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Kianifard T, Saluja M, Sarmukaddam S, Venugopalan A, Chopra A. Adjunct role of potassium-rich vegetarian diet and a novel potassium food supplement to improve pain in chronic rheumatoid arthritis on supervised standard care: a randomised controlled study. BMJ Nutr Prev Health 2024; 7:14-25. [PMID: 38966106 PMCID: PMC11221283 DOI: 10.1136/bmjnph-2023-000674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 11/27/2023] [Indexed: 07/06/2024] Open
Abstract
Introduction An earlier food survey showed dietary potassium deficiency in rheumatoid arthritis (RA). Objective To evaluate an adjunct role of oral potassium to reduce joint pain in RA. Methods 172 consenting eligible symptomatic patients (median duration 6.5 years) on standard care were randomised into an assessor blind, parallel efficacy, controlled, prospective, multiarm single-centre study (80% power, drug trial design) of 16 weeks duration-arm A (potassium-rich vegetarian diet), arm B (arm A plus novel potassium food supplement) and arm C (control, regular diet). Standard efficacy (American College of Rheumatology recommendation) and safety and diet intake (3-day recall) were assessed at monthly intervals (protocol). Standard soft-ware package (SPSS V.20) was used for statistical analysis; analysis of variance), Mann-Whitney statistic and χ2 test.; significant p<0.05, two sided). Study arms were found matched at baseline. Background RA medication remained stable. Preset target for increased potassium intake (India standards) were mostly achieved and participants remained normokalemic. Results 155 patients (90.1%) completed the study and several showed improvement (maximum improved measures in arm B). Potassium intervention was safe and well tolerated. Adverse events were mild; none caused patient withdrawal. On comparison, the mean change in pain visual analogue scale (-2.23, 95% CI -2.99 to -1.48) at week 16 (primary efficacy) from baseline was significantly superior in arm B (per protocol analysis). A high daily potassium intake (5-7.5 g, arm B) was significantly associated with low pain (study completion); OR 2.5 (univariate analysis), likelihood ratio 2.9 (logistic regression). Compliance (intervention), diet record and analysis, RA medication and absence of placebo were potential confounders. Conclusion High oral potassium intake, based on a suitable vegetarian diet and food supplement, reduced joint pain and improved RA. It was a safe adjunct to standard care, Further validation studies are required. Trial registration CTRI/2022/03/040726; Clinical Trial Registry of India.
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Affiliation(s)
- Toktam Kianifard
- Rheumatology, Center for Rheumatic Diseases, Pune, Maharashtra, India
| | - Manjit Saluja
- Rheumatology, Center for Rheumatic Diseases, Pune, Maharashtra, India
| | | | | | - Arvind Chopra
- Center for Rheumatic Diseases, Pune, Maharashtra, India
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3
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Sonkodi B, Csorba A, Marsovszky L, Balog A, Kopper B, Nagy ZZ, Resch MD. Evidence of Disruption in Neural Regeneration in Dry Eye Secondary to Rheumatoid Arthritis. Int J Mol Sci 2023; 24:ijms24087514. [PMID: 37108693 PMCID: PMC10140938 DOI: 10.3390/ijms24087514] [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: 04/07/2023] [Accepted: 04/17/2023] [Indexed: 04/29/2023] Open
Abstract
The purpose of our study was to analyze abnormal neural regeneration activity in the cornea through means of confocal microscopy in rheumatoid arthritis patients with concomitant dry eye disease. We examined 40 rheumatoid arthritis patients with variable severity and 44 volunteer age- and gender-matched healthy control subjects. We found that all examined parameters were significantly lower (p < 0.05) in rheumatoid arthritis patients as opposed to the control samples: namely, the number of fibers, the total length of the nerves, the number of branch points on the main fibers and the total nerve-fiber area. We examined further variables, such as age, sex and the duration of rheumatoid arthritis. Interestingly, we could not find a correlation between the above variables and abnormal neural structural changes in the cornea. We interpreted these findings via implementing our hypotheses. Correspondingly, one neuroimmunological link between dry eye and rheumatoid arthritis could be through the chronic Piezo2 channelopathy-induced K2P-TASK1 signaling axis. This could accelerate neuroimmune-induced sensitization on the spinal level in this autoimmune disease, with Langerhans-cell activation in the cornea and theorized downregulated Piezo1 channels in these cells. Even more importantly, suggested principal primary-damage-associated corneal keratocyte activation could be accompanied by upregulation of Piezo1. Both activation processes on the periphery would skew the plasticity of the Th17/Treg ratio, resulting in Th17/Treg imbalance in dry eye, secondary to rheumatoid arthritis. Hence, chronic somatosensory-terminal Piezo2 channelopathy-induced impaired Piezo2-Piezo1 crosstalk could result in a mixed picture of disrupted functional regeneration but upregulated morphological regeneration activity of these somatosensory axons in the cornea, providing the demonstrated abnormal neural corneal morphology.
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Affiliation(s)
- Balázs Sonkodi
- Department of Health Sciences and Sport Medicine, Hungarian University of Sports Science, 1123 Budapest, Hungary
| | - Anita Csorba
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
| | - László Marsovszky
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
| | - Attila Balog
- Department of Rheumatology and Immunology, Faculty of Medicine, Albert Szent-Györgyi Health Center, University of Szeged, 6725 Szeged, Hungary
| | - Bence Kopper
- Faculty of Kinesiology, Hungarian University of Sports Science, 1123 Budapest, Hungary
| | - Zoltán Zsolt Nagy
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
| | - Miklós D Resch
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
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4
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White IR, Kleinstein SE, Praet C, Chamberlain C, McHale D, Maia JM, Xie P, Goldstein DB, Urban TJ, Shea PR. A genome-wide screen for variants influencing certolizumab pegol response in a moderate to severe rheumatoid arthritis population. PLoS One 2022; 17:e0261165. [PMID: 35413058 PMCID: PMC9004786 DOI: 10.1371/journal.pone.0261165] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 11/24/2021] [Indexed: 12/14/2022] Open
Abstract
Certolizumab pegol (CZP) is a PEGylated Fc-free tumor necrosis factor (TNF) inhibitor antibody approved for use in the treatment of rheumatoid arthritis (RA), Crohn’s disease, psoriatic arthritis, axial spondyloarthritis and psoriasis. In a clinical trial of patients with severe RA, CZP improved disease symptoms in approximately half of patients. However, variability in CZP efficacy remains a problem for clinicians, thus, the aim of this study was to identify genetic variants predictive of CZP response. We performed a genome-wide association study (GWAS) of 302 RA patients treated with CZP in the REALISTIC trial to identify common single nucleotide polymorphisms (SNPs) associated with treatment response. Whole-exome sequencing was also performed for 74 CZP extreme responders and non-responders within the same population, as well as 1546 population controls. No common SNPs or rare functional variants were significantly associated with CZP response, though a non-significant enrichment in the RA-implicated KCNK5 gene was observed. Two SNPs near spondin-1 and semaphorin-4G approached genome-wide significance. The results of the current study did not provide an unambiguous predictor of CZP response.
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Affiliation(s)
- Ian R. White
- Experimental Medicine and Diagnostics, UCB Celltech, Slough, United Kingdom
| | - Sarah E. Kleinstein
- Institute for Genomic Medicine, Columbia University, New York, New York, United States of America
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | | | - Chris Chamberlain
- Experimental Medicine and Diagnostics, UCB Celltech, Slough, United Kingdom
| | - Duncan McHale
- Experimental Medicine and Diagnostics, UCB Celltech, Slough, United Kingdom
| | - Jessica M. Maia
- Institute for Genomic Medicine, Columbia University, New York, New York, United States of America
| | - Pingxing Xie
- Institute for Genomic Medicine, Columbia University, New York, New York, United States of America
- Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - David B. Goldstein
- Institute for Genomic Medicine, Columbia University, New York, New York, United States of America
| | - Thomas J. Urban
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Patrick R. Shea
- Institute for Genomic Medicine, Columbia University, New York, New York, United States of America
- * E-mail:
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5
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K 2P18.1 translates T cell receptor signals into thymic regulatory T cell development. Cell Res 2022; 32:72-88. [PMID: 34702947 PMCID: PMC8547300 DOI: 10.1038/s41422-021-00580-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 08/25/2021] [Indexed: 02/07/2023] Open
Abstract
It remains largely unclear how thymocytes translate relative differences in T cell receptor (TCR) signal strength into distinct developmental programs that drive the cell fate decisions towards conventional (Tconv) or regulatory T cells (Treg). Following TCR activation, intracellular calcium (Ca2+) is the most important second messenger, for which the potassium channel K2P18.1 is a relevant regulator. Here, we identify K2P18.1 as a central translator of the TCR signal into the thymus-derived Treg (tTreg) selection process. TCR signal was coupled to NF-κB-mediated K2P18.1 upregulation in tTreg progenitors. K2P18.1 provided the driving force for sustained Ca2+ influx that facilitated NF-κB- and NFAT-dependent expression of FoxP3, the master transcription factor for Treg development and function. Loss of K2P18.1 ion-current function induced a mild lymphoproliferative phenotype in mice, with reduced Treg numbers that led to aggravated experimental autoimmune encephalomyelitis, while a gain-of-function mutation in K2P18.1 resulted in increased Treg numbers in mice. Our findings in human thymus, recent thymic emigrants and multiple sclerosis patients with a dominant-negative missense K2P18.1 variant that is associated with poor clinical outcomes indicate that K2P18.1 also plays a role in human Treg development. Pharmacological modulation of K2P18.1 specifically modulated Treg numbers in vitro and in vivo. Finally, we identified nitroxoline as a K2P18.1 activator that led to rapid and reversible Treg increase in patients with urinary tract infections. Conclusively, our findings reveal how K2P18.1 translates TCR signals into thymic T cell fate decisions and Treg development, and provide a basis for the therapeutic utilization of Treg in several human disorders.
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6
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Choi SW, Woo J, Park KS, Ko J, Jeon YK, Choi SW, Yoo HY, Kho I, Kim TJ, Kim SJ. Higher expression of KCNK10 (TREK-2) K + channels and their functional upregulation by lipopolysaccharide treatment in mouse peritoneal B1a cells. Pflugers Arch 2021; 473:659-671. [PMID: 33586023 DOI: 10.1007/s00424-021-02526-1] [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: 07/14/2020] [Revised: 01/10/2021] [Accepted: 01/28/2021] [Indexed: 11/24/2022]
Abstract
Innate-like CD5+ B1a cells localized in serous cavities are activated by innate stimuli, such as lipopolysaccharide (LPS), leading to T cell-independent antibody responses. Although ion channels play crucial roles in the homeostasis and activation of immune cells, the electrophysiological properties of B1a cells have not been investigated to date. Previously, in the mouse B cell lymphoma cells, we found that the voltage-independent two-pore-domain potassium (K2P) channels generate a negative membrane potential and drive Ca2+ influx. Here, we newly compared the expression and activities of K2P channels in mouse splenic follicular B (FoB), marginal zone B (MZB), and peritoneal B1a cells. Next-generation sequencing analysis showed higher levels of transcripts for TREK-2 and TWIK-2 in B1a cells than those in FoB or MZB cells. Electrophysiological analysis, using patch clamp technique, revealed higher activity of TREK-2 with the characteristic large unitary conductance (~ 250 pS) in B1a than that in FoB or MZB cells. TREK-2 activity was further increased by LPS treatment (>2 h), which was more prominent in B1a than that in MZB or FoB cells. The cytosolic Ca2+ concentration of B cells was decreased by high-K+-induced depolarization (ΔRKCl (%)), suggesting the basal Ca2+ influx to be driven by negative membrane potential. The LPS treatment significantly increased the ΔRKCl (%) in B1a, though not in FoB and MZB cells. Our study was the first to compare the K2P channels in mouse primary B cell subsets, elucidating the functional upregulation of TREK-2 and augmentation of Ca2+ influx by the stimulation of Toll-like receptor 4 in B1a cells.
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Affiliation(s)
- Si Won Choi
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Joohan Woo
- Department of Physiology and Ion Channel Disease Research Center, Dongguk University College of Medicine, Seoul, Republic of Korea
| | - Kyung Sun Park
- Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Republic of Korea
| | - Juyeon Ko
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Young Keul Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Seong Woo Choi
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Physiology and Ion Channel Disease Research Center, Dongguk University College of Medicine, Seoul, Republic of Korea.,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hae Young Yoo
- Department of Nursing, Chung-Ang University, Seoul, Republic of Korea
| | - Inseong Kho
- Department of Immunology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Tae Jin Kim
- Department of Immunology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Republic of Korea. .,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
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7
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Fernández-Orth J, Rolfes L, Gola L, Bittner S, Andronic J, Sukhorukov VL, Sisario D, Landgraf P, Dieterich DC, Cerina M, Smalla KH, Kähne T, Budde T, Kovac S, Ruck T, Sauer M, Meuth SG. A role for TASK2 channels in the human immunological synapse. Eur J Immunol 2020; 51:342-353. [PMID: 33169379 DOI: 10.1002/eji.201948269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/30/2020] [Accepted: 11/05/2019] [Indexed: 12/29/2022]
Abstract
The immunological synapse is a transient junction that occurs when the plasma membrane of a T cell comes in close contact with an APC after recognizing a peptide from the antigen-MHC. The interaction starts when CRAC channels embedded in the T cell membrane open, flowing calcium ions into the cell. To counterbalance the ion influx and subsequent depolarization, Kv 1.3 and KCa3.1 channels are recruited to the immunological synapse, increasing the extracellular K+ concentration. These processes are crucial as they initiate gene expression that drives T cell activation and proliferation. The T cell-specific function of the K2P channel family member TASK2 channels and their role in autoimmune processes remains unclear. Using mass spectrometry analysis together with epifluorescence and super-resolution single-molecule localization microscopy, we identified TASK2 channels as novel players recruited to the immunological synapse upon stimulation. TASK2 localizes at the immunological synapse, upon stimulation with CD3 antibodies, likely interacting with these molecules. Our findings suggest that, together with Kv 1.3 and KCa3.1 channels, TASK2 channels contribute to the proper functioning of the immunological synapse, and represent an interesting treatment target for T cell-mediated autoimmune disorders.
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Affiliation(s)
| | - Leoni Rolfes
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Lukas Gola
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University Medical Center, Johannes Gutenberg-University, Mainz, Germany
| | - Joseph Andronic
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Vladimir L Sukhorukov
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Dmitri Sisario
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Peter Landgraf
- Neural Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto-von-Guericke-University, Magdeburg, Germany
| | - Daniela C Dieterich
- Neural Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto-von-Guericke-University, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Manuela Cerina
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Karl-Heinz Smalla
- Special Lab Molecular Biological Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Thilo Kähne
- Institute of Experimental Internal Medicine, Medical Faculty, Otto-von-Guericke-University, Magdeburg, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Stjepana Kovac
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Tobias Ruck
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Sven G Meuth
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
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8
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Herrmann AM, Cerina M, Bittner S, Meuth SG, Budde T. Intracellular fluoride influences TASK mediated currents in human T cells. J Immunol Methods 2020; 487:112875. [PMID: 33031794 DOI: 10.1016/j.jim.2020.112875] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 08/14/2020] [Accepted: 10/01/2020] [Indexed: 10/23/2022]
Abstract
The expression of Kv1.3 and KCa channels in human T cells is essential for maintaining cell activation, proliferation and migration during an inflammatory response. Recently, an additional residual current, sensitive to anandamide and A293, compounds specifically inhibiting currents mediated by TASK channels, was observed after complete pharmacological blockade of Kv1.3 and KCa channels. This finding was not consistently observed throughout different studies and, an in-depth review of the different recording conditions used for the electrophysiological analysis of K+ currents in T cells revealed fluoride as major anionic component of the pipette intracellular solutions in the initial studies. While fluoride is frequently used to stabilize electrophysiological recordings, it is known as G-protein activator and to influence the intracellular Ca2+ concentration, which are mechanisms known to modulate TASK channel functioning. Therefore, we systemically addressed different fluoride- and chloride-based pipette solutions in whole-cell patch-clamp experiments in human T cells and used specific blockers to identify membrane currents carried by TASK and Kv1.3 channels. We found that fluoride increased the decay time constant of K+ outward currents, reduced the degree of the sustained current component and diminished the effect of the specific TASK channels blocker A293. These findings indicate that the use of fluoride-based pipette solutions may hinder the identification of a functional TASK channel component in electrophysiological experiments.
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Affiliation(s)
- Alexander M Herrmann
- Department of Neurology with Institute of Translational Neurology, Münster University Hospital, Münster, Germany.
| | - Manuela Cerina
- Department of Neurology with Institute of Translational Neurology, Münster University Hospital, Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University of Mainz, Mainz, Germany
| | - Sven G Meuth
- Department of Neurology with Institute of Translational Neurology, Münster University Hospital, Münster, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische-Wilhems Universität Münster, Münster, Germany.
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9
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Endo K, Kito H, Tanaka R, Kajikuri J, Tanaka S, Elboray EE, Suzuki T, Ohya S. Possible Contribution of Inflammation-Associated Hypoxia to Increased K 2P5.1 K + Channel Expression in CD4 + T cells of the Mouse Model for Inflammatory Bowel Disease. Int J Mol Sci 2019; 21:ijms21010038. [PMID: 31861667 PMCID: PMC6981474 DOI: 10.3390/ijms21010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 12/10/2019] [Accepted: 12/17/2019] [Indexed: 01/03/2023] Open
Abstract
Previous studies have reported the up-regulation of the two-pore domain K+ channel K2P5.1 in the CD4+ T cells of patients with multiple sclerosis (MS) and rheumatoid arthritis (RA), as well as in a mouse model of inflammatory bowel disease (IBD). However, the mechanisms underlying this up-regulation remain unclear. Inflammation-associated hypoxia is involved in the pathogenesis of autoimmune diseases, such as IBD, MS, and RA, and T cells are exposed to a hypoxic environment during their recruitment from inflamed tissues to secondary lymphoid tissues. We herein investigated whether inflammation-associated hypoxia is attributable to the increased expression and activity of K2P5.1 in the splenic CD4+ T cells of chemically-induced IBD model mice. Significant increases in hypoxia-inducible factor (HIF)-1α transcripts and proteins were found in the splenic CD4+ T cells of the IBD model. In the activated splenic CD4+ T cells, hypoxia (1.5% O2) increased K2P5.1 expression and activity, whereas a treatment with the HIF inhibitor FM19G11 but not the selective HIF-2 inhibitor exerted the opposite effect. Hypoxia-exposed K2P5.1 up-regulation was also detected in stimulated thymocytes and the mouse T-cell line. The class III histone deacetylase sirtuin-1 (SIRT1) is a downstream molecule of HIF-1α signaling. We examined the effects of the SIRT1 inhibitor NCO-01 on K2P5.1 transcription in activated CD4+ T cells, and we found no significant effects on the K2P5.1 transcription. No acute compensatory responses of K2P3.1–K2P5.1 up-regulation were found in the CD4+ T cells of the IBD model and the hypoxia-exposed T cells. Collectively, these results suggest a mechanism for K2P5.1 up-regulation via HIF-1 in the CD4+ T cells of the IBD model.
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Affiliation(s)
- Kyoko Endo
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan; (K.E.); (R.T.); (S.T.)
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan; (H.K.); (J.K.)
| | - Hiroaki Kito
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan; (H.K.); (J.K.)
| | - Ryo Tanaka
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan; (K.E.); (R.T.); (S.T.)
| | - Junko Kajikuri
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan; (H.K.); (J.K.)
| | - Satoshi Tanaka
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan; (K.E.); (R.T.); (S.T.)
| | - Elghareeb E. Elboray
- Department of Complex Molecular Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan; (E.E.E.); (T.S.)
- Faculty of Science, South Valley University, Qena 83523, Egypt
| | - Takayoshi Suzuki
- Department of Complex Molecular Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan; (E.E.E.); (T.S.)
| | - Susumu Ohya
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan; (H.K.); (J.K.)
- Correspondence: ; Tel.: +81-52-853-8149
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10
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Eichinger P, Herrmann AM, Ruck T, Herty M, Gola L, Kovac S, Budde T, Meuth SG, Hundehege P. Human T cells in silico: Modelling dynamic intracellular calcium and its influence on cellular electrophysiology. J Immunol Methods 2018; 461:78-84. [PMID: 30158076 DOI: 10.1016/j.jim.2018.06.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 01/01/2023]
Abstract
A network of ion currents influences basic cellular T cell functions. After T cell receptor activation, changes in highly regulated calcium levels play a central role in triggering effector functions and cell differentiation. A dysregulation of these processes might be involved in the pathogenesis of several diseases. We present a mathematical model based on the NEURON simulation environment that computes dynamic calcium levels in combination with the current output of diverse ion channels (KV1.3, KCa3.1, K2P channels (TASK1-3, TRESK), VRAC, TRPM7, CRAC). In line with experimental data, the simulation shows a strong increase in intracellular calcium after T cell receptor stimulation before reaching a new, elevated calcium plateau in the T cell's activated state. Deactivation of single ion channel modules, mimicking the application of channel blockers, reveals that two types of potassium channels are the main regulators of intracellular calcium level: calcium-dependent potassium (KCa3.1) and two-pore-domain potassium (K2P) channels.
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Affiliation(s)
- Paul Eichinger
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München TUM, Ismaninger Straße 22, 81675 Munich, Germany
| | - Alexander M Herrmann
- Department of Neurology with Institute of Translational Neurology, Albert-Schweitzer-Campus 1, Building A1, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Tobias Ruck
- Department of Neurology with Institute of Translational Neurology, Albert-Schweitzer-Campus 1, Building A1, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Michael Herty
- RWTH Aachen University, Mathematics (Continuous optimization), Templergraben 55, 52056 Aachen, Germany
| | - Lukas Gola
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München TUM, Ismaninger Straße 22, 81675 Munich, Germany
| | - Stjepana Kovac
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München TUM, Ismaninger Straße 22, 81675 Munich, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Robert-Koch-Str. 27a, 48149 Münster, Germany
| | - Sven G Meuth
- Department of Neurology with Institute of Translational Neurology, Albert-Schweitzer-Campus 1, Building A1, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Petra Hundehege
- Department of Neurology with Institute of Translational Neurology, Albert-Schweitzer-Campus 1, Building A1, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
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11
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Phosphatidylinositol (4,5)-bisphosphate dynamically regulates the K 2P background K + channel TASK-2. Sci Rep 2017; 7:45407. [PMID: 28358046 PMCID: PMC5371824 DOI: 10.1038/srep45407] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 02/23/2017] [Indexed: 12/22/2022] Open
Abstract
Two-pore domain K2P K+ channels responsible for the background K+ conductance and the resting membrane potential, are also finely regulated by a variety of chemical, physical and physiological stimuli. Hormones and transmitters acting through Gq protein-coupled receptors (GqPCRs) modulate the activity of various K2P channels but the signalling involved has remained elusive, in particular whether dynamic regulation by membrane PI(4,5)P2, common among other classes of K+ channels, affects K2P channels is controversial. Here we show that K2P K+ channel TASK-2 requires PI(4,5)P2 for activity, a dependence that accounts for its run down in the absence of intracellular ATP and its full recovery by addition of exogenous PI(4,5)P2, its inhibition by low concentrations of polycation PI scavengers, and inhibition by PI(4,5)P2 depletion from the membrane. Comprehensive mutagenesis suggests that PI(4,5)P2 interaction with TASK-2 takes place at C-terminus where three basic aminoacids are identified as being part of a putative binding site.
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12
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Fernández-Orth J, Ehling P, Ruck T, Pankratz S, Hofmann MS, Landgraf P, Dieterich DC, Smalla KH, Kähne T, Seebohm G, Budde T, Wiendl H, Bittner S, Meuth SG. 14-3-3 Proteins regulate K 2P 5.1 surface expression on T lymphocytes. Traffic 2016; 18:29-43. [PMID: 27743426 DOI: 10.1111/tra.12455] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 10/12/2016] [Accepted: 10/12/2016] [Indexed: 01/10/2023]
Abstract
K2P 5.1 channels (also called TASK-2 or Kcnk5) have already been shown to be relevant in the pathophysiology of autoimmune disease because they are known to be upregulated on peripheral and central T lymphocytes of multiple sclerosis (MS) patients. Moreover, overexpression of K2P 5.1 channels in vitro provokes enhanced T-cell effector functions. However, the molecular mechanisms regulating intracellular K2P 5.1 channel trafficking are unknown so far. Thus, the aim of the study is to elucidate the trafficking of K2P 5.1 channels on T lymphocytes. Using mass spectrometry analysis, we have identified 14-3-3 proteins as novel binding partners of K2P 5.1 channels. We show that a non-classical 14-3-3 consensus motif (R-X-X-pT/S-x) at the channel's C-terminus allows the binding between K2P 5.1 and 14-3-3. The mutant K2P 5.1/S266A diminishes the protein-protein interaction and reduces the amplitude of membrane currents. Application of a non-peptidic 14-3-3 inhibitor (BV02) significantly reduces the number of wild-type channels in the plasma membrane, whereas the drug has no effect on the trafficking of the mutated channel. Furthermore, blocker application reduces T-cell effector functions. Taken together, we demonstrate that 14-3-3 interacts with K2P 5.1 and plays an important role in channel trafficking.
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Affiliation(s)
| | - Petra Ehling
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Tobias Ruck
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Susann Pankratz
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | | | - Peter Landgraf
- Neural Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto von-Guericke-University, Magdeburg, Germany
| | - Daniela C Dieterich
- Neural Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto von-Guericke-University, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Otto von-Guericke-University, Magdeburg, Germany
| | - Karl-Heinz Smalla
- Special Lab Molecular Biological Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Thilo Kähne
- Institute of Experimental Internal Medicine, Medical Faculty, Otto-von-Guericke-University, Magdeburg, Germany
| | - Guiscard Seebohm
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Thomas Budde
- Institute for Physiology I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Heinz Wiendl
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University Medical Center, Johannes Gutenberg-University, Mainz, Germany
| | - Sven G Meuth
- Department of Neurology, Westfälische Wilhelms-Universität, Münster, Germany
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13
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Tagishi K, Shimizu A, Endo K, Kito H, Niwa S, Fujii M, Ohya S. Defective splicing of the background K+ channel K2P5.1 by the pre-mRNA splicing inhibitor, pladienolide B in lectin-activated mouse splenic CD4+ T cells. J Pharmacol Sci 2016; 132:205-209. [DOI: 10.1016/j.jphs.2016.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 10/20/2016] [Accepted: 10/23/2016] [Indexed: 11/24/2022] Open
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14
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Ehling P, Meuth P, Eichinger P, Herrmann AM, Bittner S, Pawlowski M, Pankratz S, Herty M, Budde T, Meuth SG. Human T cells in silico: Modelling their electrophysiological behaviour in health and disease. J Theor Biol 2016; 404:236-250. [PMID: 27288542 DOI: 10.1016/j.jtbi.2016.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/27/2016] [Accepted: 06/01/2016] [Indexed: 01/27/2023]
Abstract
Although various types of ion channels are known to have an impact on human T cell effector functions, their exact mechanisms of influence are still poorly understood. The patch clamp technique is a well-established method for the investigation of ion channels in neurons and T cells. However, small cell sizes and limited selectivity of pharmacological blockers restrict the value of this experimental approach. Building a realistic T cell computer model therefore can help to overcome these kinds of limitations as well as reduce the overall experimental effort. The computer model introduced here was fed off ion channel parameters from literature and new experimental data. It is capable of simulating the electrophysiological behaviour of resting and activated human CD4(+) T cells under basal conditions and during extracellular acidification. The latter allows for the very first time to assess the electrophysiological consequences of tissue acidosis accompanying most forms of inflammation.
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Affiliation(s)
- Petra Ehling
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany.
| | - Patrick Meuth
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Paul Eichinger
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany; Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München TUM, Ismaninger Strasse 22, 81675 Munich, Germany
| | - Alexander M Herrmann
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Matthias Pawlowski
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany; Wellcome Trust and MRC Cambridge Stem Cell Institute, and Anne McLaren Laboratory for Regenerative Medicine, University of Cambridge, West Forvie Building, Forvie Site, Robinson Way, Cambridge, UK
| | - Susann Pankratz
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Michael Herty
- RWTH Aachen University, Mathematics (Continuous optimization), Templergraben 55, 52056 Aachen, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Robert-Koch-Str. 27a, 48149 Münster, Germany
| | - Sven G Meuth
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
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15
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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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16
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Nakakura S, Matsui M, Sato A, Ishii M, Endo K, Muragishi S, Murase M, Kito H, Niguma H, Kurokawa N, Fujii M, Araki M, Araki K, Ohya S. Pathophysiological significance of the two-pore domain K(+) channel K2P5.1 in splenic CD4(+)CD25(-) T cell subset from a chemically-induced murine inflammatory bowel disease model. Front Physiol 2015; 6:299. [PMID: 26578971 PMCID: PMC4621418 DOI: 10.3389/fphys.2015.00299] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/09/2015] [Indexed: 01/17/2023] Open
Abstract
The alkaline pH-activated, two-pore domain K(+) channel K2P5.1 (also known as TASK2/KCNK5) plays an important role in maintaining the resting membrane potential, and contributes to the control of Ca(2+) signaling in several types of cells. Recent studies highlighted the potential role of the K2P5.1 K(+) channel in the pathogenesis of autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. The aim of the present study was to elucidate the pathological significance of the K2P5.1 K(+) channel in inflammatory bowel disease (IBD). The degrees of colitis, colonic epithelial damage, and colonic inflammation were quantified in the dextran sulfate sodium-induced mouse IBD model by macroscopic and histological scoring systems. The expression and functional activity of K2P5.1 in splenic CD4(+) T cells were measured using real-time PCR, Western blot, and fluorescence imaging assays. A significant increase was observed in the expression of K2P5.1 in the splenic CD4(+) T cells of the IBD model. Concomitant with this increase, the hyperpolarization response induced by extracellular alkaline pH was significantly larger in the IBD model with the corresponding intracellular Ca(2+) rises. The expression of K2P5.1 was higher in CD4(+)CD25(-) T cells than in CD4(+)CD25(+) regulatory T cells. The knockout of K2P5.1 in mice significantly suppressed the disease responses implicated in the IBD model. Alternations in intracellular Ca(2+) signaling following the dysregulated expression of K2P5.1 were associated with the disease pathogenesis of IBD. The results of the present study suggest that the K2P5.1 K(+) channel in CD4(+)CD25(-) T cell subset is a potential therapeutic target and biomarker for IBD.
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Affiliation(s)
- Sawa Nakakura
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Miki Matsui
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Aya Sato
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Mizuki Ishii
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Kyoko Endo
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Sayaka Muragishi
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Miki Murase
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Hiroaki Kito
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Hiroki Niguma
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Natsumi Kurokawa
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Masanori Fujii
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Masatake Araki
- Institute of Resource Development and Analysis, Kumamoto University Kumamoto, Japan
| | - Kimi Araki
- Institute of Resource Development and Analysis, Kumamoto University Kumamoto, Japan
| | - Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
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17
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Endo K, Kurokawa N, Kito H, Nakakura S, Fujii M, Ohya S. Molecular identification of the dominant-negative, splicing isoform of the two-pore domain K(+) channel K(2P)5.1 in lymphoid cells and enhancement of its expression by splicing inhibition. Biochem Pharmacol 2015; 98:440-52. [PMID: 26475531 DOI: 10.1016/j.bcp.2015.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/01/2015] [Indexed: 12/20/2022]
Abstract
The two-pore domain background K(+) channel K2P5.1 is expected as a possible therapeutic target for autoimmune and inflammatory disorders and cancers because it plays an important role in maintaining the resting membrane potential and regulation of Ca(2+) signaling in T lymphocytes and cancer cells. However, the lack of selective K2P5.1 blockers has led to difficulties conducting experimental studies on this K(+) channel. We identified a novel splicing isoform of K2P5.1, K2P5.1B from the mammalian spleen, which lacked the N-terminus of full-length K2P5.1A. A co-immunoprecipitation assay using mice spleen lysates revealed an interaction between K2P5.1A and K2P5.1B in the cytoplasmic C-terminal domain. In a heterologous HEK293 expression system, K2P5.1B inhibited the trafficking of K2P5.1A to the plasma membrane. The alkaline pHe-induced hyperpolarizing response was significantly suppressed in K2P5.1B-transfected human leukemia K562 cells. Enhancement in cell proliferation by the overexpression of K2P5.1A in K562 was significantly prevented by the transfection of K2P5.1B. The spliceosome inhibitor pladienolide B significantly enhanced the relative expression of K2P5.1B in K562, resulting in decreases in the activity of K2P5.1A. K2P5.1B suppresses the function of the K2P5.1 K(+) channel in a dominant-negative manner, suggesting that the mRNA splicing mechanisms underlying the transcriptional regulation of K2P5.1B may be a new therapeutic strategy for autoimmune and inflammatory disorders and cancers.
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Affiliation(s)
- Kyoko Endo
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Natsumi Kurokawa
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Hiroaki Kito
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Sawa Nakakura
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Masanori Fujii
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
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18
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Bittner S, Bobak N, Hofmann MS, Schuhmann MK, Ruck T, Göbel K, Brück W, Wiendl H, Meuth SG. Murine K2P5.1 Deficiency Has No Impact on Autoimmune Neuroinflammation due to Compensatory K2P3.1- and KV1.3-Dependent Mechanisms. Int J Mol Sci 2015. [PMID: 26213925 PMCID: PMC4581175 DOI: 10.3390/ijms160816880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lymphocytes express potassium channels that regulate physiological cell functions, such as activation, proliferation and migration. Expression levels of K2P5.1 (TASK2; KCNK5) channels belonging to the family of two-pore domain potassium channels have previously been correlated to the activity of autoreactive T lymphocytes in patients with multiple sclerosis and rheumatoid arthritis. In humans, K2P5.1 channels are upregulated upon T cell stimulation and influence T cell effector functions. However, a further clinical translation of targeting K2P5.1 is currently hampered by a lack of highly selective inhibitors, making it necessary to evaluate the impact of KCNK5 in established preclinical animal disease models. We here demonstrate that K2P5.1 knockout (K2P5.1−/−) mice display no significant alterations concerning T cell cytokine production, proliferation rates, surface marker molecules or signaling pathways. In an experimental model of autoimmune neuroinflammation, K2P5.1−/− mice show a comparable disease course to wild-type animals and no major changes in the peripheral immune system or CNS compartment. A compensatory upregulation of the potassium channels K2P3.1 and KV1.3 seems to counterbalance the deletion of K2P5.1. As an alternative model mimicking autoimmune neuroinflammation, experimental autoimmune encephalomyelitis in the common marmoset has been proposed, especially for testing the efficacy of new potential drugs. Initial experiments show that K2P5.1 is functionally expressed on marmoset T lymphocytes, opening up the possibility for assessing future K2P5.1-targeting drugs.
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Affiliation(s)
- Stefan Bittner
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, Münster 48149, Germany.
| | - Nicole Bobak
- LabEx ICST, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université de Nice-Sophia Antipolis, Valbonne 06560, France.
| | - Majella-Sophie Hofmann
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, Münster 48149, Germany.
| | | | - Tobias Ruck
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, Münster 48149, Germany.
| | - Kerstin Göbel
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, Münster 48149, Germany.
| | - Wolfgang Brück
- Department of Neuropathology, University Medical Center, Georg August University, Göttingen 37073, Germany.
| | - Heinz Wiendl
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, Münster 48149, Germany.
| | - Sven G Meuth
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, Münster 48149, Germany.
- Department of Physiology I-Neuropathophysiology, University of Münster, Münster 48149, Germany .
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19
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Placing ion channels into a signaling network of T cells: from maturing thymocytes to healthy T lymphocytes or leukemic T lymphoblasts. BIOMED RESEARCH INTERNATIONAL 2015; 2015:750203. [PMID: 25866806 PMCID: PMC4383400 DOI: 10.1155/2015/750203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/19/2014] [Indexed: 12/20/2022]
Abstract
T leukemogenesis is a multistep process, where the genetic errors during T cell maturation cause the healthy progenitor to convert into the leukemic precursor that lost its ability to differentiate but possesses high potential for proliferation, self-renewal, and migration. A new misdirecting "leukemogenic" signaling network appears, composed by three types of participants which are encoded by (1) genes implicated in determined stages of T cell development but deregulated by translocations or mutations, (2) genes which normally do not participate in T cell development but are upregulated, and (3) nondifferentially expressed genes which become highly interconnected with genes expressed differentially. It appears that each of three groups may contain genes coding ion channels. In T cells, ion channels are implicated in regulation of cell cycle progression, differentiation, activation, migration, and cell death. In the present review we are going to reveal a relationship between different genetic defects, which drive the T cell neoplasias, with calcium signaling and ion channels. We suggest that changes in regulation of various ion channels in different types of the T leukemias may provide the intracellular ion microenvironment favorable to maintain self-renewal capacity, arrest differentiation, induce proliferation, and enhance motility.
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20
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Jukkola P, Gu C. Regulation of neurovascular coupling in autoimmunity to water and ion channels. Autoimmun Rev 2015; 14:258-67. [PMID: 25462580 PMCID: PMC4303502 DOI: 10.1016/j.autrev.2014.11.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 11/15/2014] [Indexed: 12/27/2022]
Abstract
Much progress has been made in understanding autoimmune channelopathies, but the underlying pathogenic mechanisms are not always clear due to broad expression of some channel proteins. Recent studies show that autoimmune conditions that interfere with neurovascular coupling in the central nervous system (CNS) can lead to neurodegeneration. Cerebral blood flow that meets neuronal activity and metabolic demand is tightly regulated by local neural activity. This process of reciprocal regulation involves coordinated actions of a number of cell types, including neurons, glia, and vascular cells. In particular, astrocytic endfeet cover more than 90% of brain capillaries to assist blood-brain barrier (BBB) function, and wrap around synapses and nodes of Ranvier to communicate with neuronal activity. In this review, we highlight four types of channel proteins that are expressed in astrocytes, regarding their structures, biophysical properties, expression and distribution patterns, and related diseases including autoimmune disorders. Water channel aquaporin 4 (AQP4) and inwardly rectifying potassium (Kir4.1) channels are concentrated in astrocytic endfeet, whereas some voltage-gated Ca(2+) and two-pore domain K(+) channels are expressed throughout the cell body of reactive astrocytes. More channel proteins are found in astrocytes under normal and abnormal conditions. This research field will contribute to a better understanding of pathogenic mechanisms underlying autoimmune disorders.
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Affiliation(s)
- Peter Jukkola
- Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Chen Gu
- Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA.
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21
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Ehling P, Cerina M, Budde T, Meuth SG, Bittner S. The CNS under pathophysiologic attack--examining the role of K₂p channels. Pflugers Arch 2014; 467:959-72. [PMID: 25482672 DOI: 10.1007/s00424-014-1664-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/17/2014] [Accepted: 11/28/2014] [Indexed: 10/24/2022]
Abstract
Members of the two-pore domain K(+) channel (K2P) family are increasingly recognized as being potential targets for therapeutic drugs and could play a role in the diagnosis and treatment of neurologic disorders. Their broad and diverse expression pattern in pleiotropic cell types, importance in cellular function, unique biophysical properties, and sensitivity toward pathophysiologic parameters represent the basis for their involvement in disorders of the central nervous system (CNS). This review will focus on multiple sclerosis (MS) and stroke, as there is growing evidence for the involvement of K2P channels in these two major CNS disorders. In MS, TASK1-3 channels are expressed on T lymphocytes and are part of a signaling network regulating Ca(2+)- dependent pathways that are mandatory for T cell activation, differentiation, and effector functions. In addition, TASK1 channels are involved in neurodegeneration, resulting in autoimmune attack of CNS cells. On the blood-brain barrier, TREK1 channels regulate immune cell trafficking under autoinflammatory conditions. Cerebral ischemia shares some pathophysiologic similarities with MS, including hypoxia and extracellular acidosis. On a cellular level, K2P channels can have both proapoptotic and antiapoptotic effects, either promoting neurodegeneration or protecting neurons from ischemic cell death. TASK1 and TREK1 channels have a neuroprotective effect on stroke development, whereas TASK2 channels have a detrimental effect on neuronal survival under ischemic conditions. Future research in preclinical models is needed to provide a more detailed understanding of the contribution of K2P channel family members to neurologic disorders, before translation to the clinic is an option.
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Affiliation(s)
- Petra Ehling
- Department of Neurology, University of Münster, Münster, Germany,
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22
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Göb E, Bittner S, Bobak N, Kraft P, Göbel K, Langhauser F, Homola GA, Brede M, Budde T, Meuth SG, Kleinschnitz C. The two-pore domain potassium channel KCNK5 deteriorates outcome in ischemic neurodegeneration. Pflugers Arch 2014; 467:973-87. [PMID: 25315980 DOI: 10.1007/s00424-014-1626-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 09/29/2014] [Accepted: 10/01/2014] [Indexed: 01/05/2023]
Abstract
Potassium channels can fulfill both beneficial and detrimental roles in neuronal damage during ischemic stroke. Earlier studies have characterized a neuroprotective role of the two-pore domain potassium channels KCNK2 (TREK1) and KCNK3 (TASK1). Protective neuronal hyperpolarization and prevention of intracellular Ca(2+) overload and glutamate excitotoxicity were suggested to be the underlying mechanisms. We here identify an unexpected role for the related KCNK5 channel in a mouse model of transient middle cerebral artery occlusion (tMCAO). KCNK5 is strongly upregulated on neurons upon cerebral ischemia, where it is most likely involved in the induction of neuronal apoptosis. Hypoxic conditions elevated neuronal expression levels of KCNK5 in acute brain slices and primary isolated neuronal cell cultures. In agreement, KCNK5 knockout mice had significantly reduced infarct volumes and improved neurologic function 24 h after 60 min of tMCAO and this protective effect was preserved at later stages of infarct development. KCNK5 deficiency resulted in a significantly reduced number of apoptotic neurons, a downregulation of pro-apoptotic and upregulation of anti-apoptotic factors. Results of adoptive transfer experiments of wild-type and Kcnk5 (-/-) immune cells into Rag1 (-/-) mice prior to tMCAO exclude a major role of KCNK5 in poststroke inflammatory reactions. In summary, KCNK5 expression is induced on neurons under ischemic conditions where it most likely exerts pro-apoptotic effects. Hence, pharmacological blockade of KCNK5 might have therapeutic potential in preventing ischemic neurodegeneration.
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Affiliation(s)
- Eva Göb
- Department of Neurology, University Clinics Würzburg, Würzburg, Germany
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Xiao F, Zhang HY, Liu YJ, Zhao D, Shan YX, Jiang YF. Higher frequency of peripheral blood interleukin 21 positive follicular helper T cells in patients with ankylosing spondylitis. J Rheumatol 2013; 40:2029-37. [PMID: 24187103 DOI: 10.3899/jrheum.130125] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The role of follicular Th (TFH) cells remains unclear in the pathogenesis of ankylosing spondylitis (AS). Our study examined the frequency of different subsets of circulating CXCR5+CD4+ T cells in patients with AS before and after receiving therapy. METHODS Percentages of peripheral blood inducible costimulator (ICOS)+, programmed death 1 (PD-1)+, and interleukin 21 (IL-21)+ CXCR5+CD4+ T cells in 26 patients with AS and 12 healthy controls (HC) were examined by flow cytometry, and the disease activity of individual patients was measured by Bath AS Disease Activity Index (BASDAI). The concentrations of serum IL-21, IgG, IgA, IgM, and C-reactive protein (CRP) were examined and the values of erythrocyte sedimentation rate (ESR) were measured. The potential association among these measures was analyzed. RESULTS In comparison with that in HC, significantly increased percentages of CXCR5+CD4+, CXCR5+CD4+PD-1+, and CXCR5+CD4+IL-21+, but not CXCR5+CD4+ICOS+ and PD-1+ICOS+CXCR5+CD4+ T cells, and elevated concentrations of serum IL-21 were detected in patients with AS (p = 0.001, p = 0.012, p < 0.001, p = 0.233, p = 0.216, p < 0.001, respectively). Treatment with meloxicam, thalidomide, and etanercept for 1 month significantly reduced percentages of IL-21+CXCR5+CD4+ T cells and concentrations of serum IL-21 (p < 0.001, p < 0.001, respectively), accompanied by significantly minimized disease activity in drug responders, but not in the drug nonresponders. Further, percentages of IL-21+CXCR5+CD4+ T cells were positively correlated with BASDAI in patients (r = 0.6, p = 0.0012) and in the drug-responders 1 month after treatment (r = 0.68, p = 0.005), while the percentages of PD-1+CXCR5+CD4+ T cells were negatively correlated with BASDAI (r = -0.58, p = 0.0018). CONCLUSION These data suggest that IL-21+CXCR5+CD4+ T cells may be associated with development of AS and that the frequency of IL-21+CXCR5+CD4+ T cells may be a biomarker for evaluation of disease activity and drug responses in patients with AS, particularly in drug-responding patients.
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Affiliation(s)
- Fei Xiao
- From the Key Laboratory of Zoonosis Research, Ministry of Education, the Second Part of First Hospital, Jilin University, Changchun, 130032, China
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Bittner S, Meuth SG. Targeting ion channels for the treatment of autoimmune neuroinflammation. Ther Adv Neurol Disord 2013; 6:322-36. [PMID: 23997817 DOI: 10.1177/1756285613487782] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Pharmacological targeting of ion channels has long been recognized as an attractive strategy for the treatment of various diseases. Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system with a prominent neurodegenerative component. A multitude of different cell types are involved in the complex pathophysiology of this disorder, including cells of the immune system (e.g. T and B lymphocytes and microglia), the neurovascular unit (e.g. endothelial cells and astrocytes) and the central nervous system (e.g. astrocytes and neurons). The pleiotropic expression and function of ion channels gives rise to the attractive opportunity of targeting different players and pathophysiological aspects of MS by the modulation of ion channel function in a cell-type and context-specific manner. We discuss the emerging knowledge about ion channels in the context of autoimmune neuroinflammation. While some pharmacological targets are at the edge of clinical translation, others have only recently been discovered and are still under investigation. Special focus is given to those candidates that could be attractive novel targets for future therapeutic approaches in neuroimmune autoinflammation.
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Affiliation(s)
- Stefan Bittner
- Department of Neurology, University of Münster, Münster, Germany
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Andronic J, Bobak N, Bittner S, Ehling P, Kleinschnitz C, Herrmann AM, Zimmermann H, Sauer M, Wiendl H, Budde T, Meuth SG, Sukhorukov VL. Identification of two-pore domain potassium channels as potent modulators of osmotic volume regulation in human T lymphocytes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:699-707. [PMID: 23041580 DOI: 10.1016/j.bbamem.2012.09.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 09/21/2012] [Accepted: 09/27/2012] [Indexed: 11/17/2022]
Abstract
Many functions of T lymphocytes are closely related to cell volume homeostasis and regulation, which utilize a complex network of membrane channels for anions and cations. Among the various potassium channels, the voltage-gated K(V)1.3 is well known to contribute greatly to the osmoregulation and particularly to the potassium release during the regulatory volume decrease (RVD) of T cells faced with hypotonic environment. Here we address a putative role of the newly identified two-pore domain (K(2P)) channels in the RVD of human CD4(+) T lymphocytes, using a series of potent well known channel blockers. In the present study, the pharmacological profiles of RVD inhibition revealed K(2P)5.1 and K(2P)18.1 as the most important K(2P) channels involved in the RVD of both naïve and stimulated T cells. The impact of chemical inhibition of K(2P)5.1 and K(2P)18.1 on the RVD was comparable to that of K(V)1.3. K(2P)9.1 also notably contributed to the RVD of T cells but the extent of this contribution and its dependence on the activation status could not be unambiguously resolved. In summary, our data provide first evidence that the RVD-related potassium efflux from human T lymphocytes relies on K(2P) channels.
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Affiliation(s)
- Joseph Andronic
- University of Wuerzburg, Lehrstuhl für Biotechnologie und Biophysik, Biozentrum, Am Hubland, 97074 Wuerzburg, Germany
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