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Szekér P, Bodó T, Klima K, Csóti Á, Hanh NN, Murányi J, Hajdara A, Szántó TG, Panyi G, Megyeri M, Péterfi Z, Farkas S, Gyöngyösi N, Hornyák P. KcsA-Kv1.x chimeras with complete ligand-binding sites provide improved predictivity for screening selective Kv1.x blockers. J Biol Chem 2024; 300:107155. [PMID: 38479597 PMCID: PMC11002876 DOI: 10.1016/j.jbc.2024.107155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/12/2024] [Accepted: 03/06/2024] [Indexed: 04/08/2024] Open
Abstract
Despite significant advances in the development of therapeutic interventions targeting autoimmune diseases and chronic inflammatory conditions, lack of effective treatment still poses a high unmet need. Modulating chronically activated T cells through the blockade of the Kv1.3 potassium channel is a promising therapeutic approach; however, developing selective Kv1.3 inhibitors is still an arduous task. Phage display-based high throughput peptide library screening is a rapid and robust approach to develop promising drug candidates; however, it requires solid-phase immobilization of target proteins with their binding site preserved. Historically, the KcsA bacterial channel chimera harboring only the turret region of the human Kv1.3 channel was used for screening campaigns. Nevertheless, literature data suggest that binding to this type of chimera does not correlate well with blocking potency on the native Kv1.3 channels. Therefore, we designed and successfully produced advanced KcsA-Kv1.3, KcsA-Kv1.1, and KcsA-Kv1.2 chimeric proteins in which both the turret and part of the filter regions of the human Kv1.x channels were transferred. These T+F (turret-filter) chimeras showed superior peptide ligand-binding predictivity compared to their T-only versions in novel phage ELISA assays. Phage ELISA binding and competition results supported with electrophysiological data confirmed that the filter region of KcsA-Kv1.x is essential for establishing adequate relative affinity order among selected peptide toxins (Vm24 toxin, Hongotoxin-1, Kaliotoxin-1, Maurotoxin, Stichodactyla toxin) and consequently obtaining more reliable selectivity data. These new findings provide a better screening tool for future drug development efforts and offer insight into the target-ligand interactions of these therapeutically relevant ion channels.
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Affiliation(s)
| | | | | | | | | | | | | | - Tibor Gábor Szántó
- Faculty of Medicine, Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary
| | - György Panyi
- Faculty of Medicine, Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary
| | | | | | | | - Norbert Gyöngyösi
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary
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Jusztus V, Medyouni G, Bagosi A, Lampé R, Panyi G, Matolay O, Maka E, Krasznai ZT, Vörös O, Hajdu P. Activity of Potassium Channels in CD8 + T Lymphocytes: Diagnostic and Prognostic Biomarker in Ovarian Cancer? Int J Mol Sci 2024; 25:1949. [PMID: 38396628 PMCID: PMC10888402 DOI: 10.3390/ijms25041949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/31/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
CD8+ T cells play a role in the suppression of tumor growth and immunotherapy. Ion channels control the Ca2+-dependent function of CD8+ lymphocytes such as cytokine/granzyme production and tumor killing. Kv1.3 and KCa3.1 K+ channels stabilize the negative membrane potential of T cells to maintain Ca2+ influx through CRAC channels. We assessed the expression of Kv1.3, KCa3.1 and CRAC in CD8+ cells from ovarian cancer (OC) patients (n = 7). We found that the expression level of Kv1.3 was higher in patients with malignant tumors than in control or benign tumor groups while the KCa3.1 activity was lower in the malignant tumor group as compared to the others. We demonstrated that the Ca2+ response in malignant tumor patients is higher compared to control groups. We propose that altered Kv1.3 and KCa3.1 expression in CD8+ cells in OC could be a reporter and may serve as a biomarker in diagnostics and that increased Ca2+ response through CRAC may contribute to the impaired CD8+ function.
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Affiliation(s)
- Vivien Jusztus
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (V.J.); (G.M.); (A.B.); (G.P.); (O.V.)
| | - Ghofrane Medyouni
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (V.J.); (G.M.); (A.B.); (G.P.); (O.V.)
| | - Adrienn Bagosi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (V.J.); (G.M.); (A.B.); (G.P.); (O.V.)
| | - Rudolf Lampé
- Department of Gynecology and Obstetrics, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (R.L.); (O.M.); (E.M.); (Z.T.K.)
| | - György Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (V.J.); (G.M.); (A.B.); (G.P.); (O.V.)
| | - Orsolya Matolay
- Department of Gynecology and Obstetrics, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (R.L.); (O.M.); (E.M.); (Z.T.K.)
| | - Eszter Maka
- Department of Gynecology and Obstetrics, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (R.L.); (O.M.); (E.M.); (Z.T.K.)
| | - Zoárd Tibor Krasznai
- Department of Gynecology and Obstetrics, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (R.L.); (O.M.); (E.M.); (Z.T.K.)
| | - Orsolya Vörös
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (V.J.); (G.M.); (A.B.); (G.P.); (O.V.)
| | - Péter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary; (V.J.); (G.M.); (A.B.); (G.P.); (O.V.)
- Division of Dental Biochemistry, Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
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Yuan X, Han S, Manyande A, Gao F, Wang J, Zhang W, Tian X. Spinal voltage-gated potassium channel Kv1.3 contributes to neuropathic pain via the promotion of microglial M1 polarization and activation of the NLRP3 inflammasome. Eur J Pain 2023; 27:289-302. [PMID: 36440534 DOI: 10.1002/ejp.2059] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/06/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUD Studies have shown that the activation of microglia is the main mechanism of neuropathic pain. Kv1.3 channel is a novel therapeutic target for treating neuroinflammatory disorders due to its crucial role in subsets of microglial cells. As such, it may be involved in the processes of neuropathic pain, however, whether Kv1.3 plays a role in neuroinflammation following peripheral nerve injury is unclear. METHOD The spared nerve injury model (SNI) was used to establish neuropathic pain. Western blot and immunofluorescence were used to examine the effect of Kv1.3 in the SNI rats. PAP-1, a Kv1.3 specific blocker was administered to alleviate neuropathic pain in the SNI rats. RESULTS Neuropathic pain and allodynia occurred after SNI, the levels of M1 (CD68, iNos) and M2 (CD206, Arg-1) phenotypes were up-regulated in the spinal cord, and the protein levels of NLRP3, caspase-1 and IL-1β were also increased. Pharmacological blocking of Kv1.3 with PAP-1 alleviated hyperpathia induced by SNI. Meanwhile, intrathecal injection of PAP-1 reduced M1 polarization and decreased NLRP3, caspase-1 and IL-1β expressions of protein levels. CONCLUSION Our research indicates that the Kv1.3 channel in the spinal cord contributes to neuropathic pain by promoting microglial M1 polarization and activating the NLRP3 inflammasome.
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Affiliation(s)
- Xiaoman Yuan
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
| | - Siyi Han
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
| | - Anne Manyande
- School of Human and Social Sciences, University of West London, London, UK
| | - Feng Gao
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
| | - Jie Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Wen Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
| | - Xuebi Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
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Selvakumar P, Fernández-Mariño AI, Khanra N, He C, Paquette AJ, Wang B, Huang R, Smider VV, Rice WJ, Swartz KJ, Meyerson JR. Structures of the T cell potassium channel Kv1.3 with immunoglobulin modulators. Nat Commun 2022; 13:3854. [PMID: 35788586 PMCID: PMC9253088 DOI: 10.1038/s41467-022-31285-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 06/07/2022] [Indexed: 11/09/2022] Open
Abstract
The Kv1.3 potassium channel is expressed abundantly on activated T cells and mediates the cellular immune response. This role has made the channel a target for therapeutic immunomodulation to block its activity and suppress T cell activation. Here, we report structures of human Kv1.3 alone, with a nanobody inhibitor, and with an antibody-toxin fusion blocker. Rather than block the channel directly, four copies of the nanobody bind the tetramer's voltage sensing domains and the pore domain to induce an inactive pore conformation. In contrast, the antibody-toxin fusion docks its toxin domain at the extracellular mouth of the channel to insert a critical lysine into the pore. The lysine stabilizes an active conformation of the pore yet blocks ion permeation. This study visualizes Kv1.3 pore dynamics, defines two distinct mechanisms to suppress Kv1.3 channel activity with exogenous inhibitors, and provides a framework to aid development of emerging T cell immunotherapies.
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Affiliation(s)
- Purushotham Selvakumar
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - Ana I Fernández-Mariño
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Nandish Khanra
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - Changhao He
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - Alice J Paquette
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY, USA
| | - Bing Wang
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY, USA
| | - Ruiqi Huang
- Applied Biomedical Science Institute, San Diego, CA, USA
- Minotaur Therapeutics, San Diego, CA, USA
| | - Vaughn V Smider
- Applied Biomedical Science Institute, San Diego, CA, USA
- Minotaur Therapeutics, San Diego, CA, USA
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - William J Rice
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY, USA
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Joel R Meyerson
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA.
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Sebestyén V, Nagy É, Mocsár G, Volkó J, Szilágyi O, Kenesei Á, Panyi G, Tóth K, Hajdu P, Vámosi G. Role of C-Terminal Domain and Membrane Potential in the Mobility of Kv1.3 Channels in Immune Synapse Forming T Cells. Int J Mol Sci 2022; 23:ijms23063313. [PMID: 35328733 PMCID: PMC8952507 DOI: 10.3390/ijms23063313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 02/01/2023] Open
Abstract
Voltage-gated Kv1.3 potassium channels are essential for maintaining negative membrane potential during T-cell activation. They interact with membrane-associated guanylate kinases (MAGUK-s) via their C-terminus and with TCR/CD3, leading to enrichment at the immunological synapse (IS). Molecular interactions and mobility may impact each other and the function of these proteins. We aimed to identify molecular determinants of Kv1.3 mobility, applying fluorescence correlation spectroscopy on human Jurkat T-cells expressing WT, C-terminally truncated (ΔC), and non-conducting mutants of mGFP-Kv1.3. ΔC cannot interact with MAGUK-s and is not enriched at the IS, whereas cells expressing the non-conducting mutant are depolarized. Here, we found that in standalone cells, mobility of ΔC increased relative to the WT, likely due to abrogation of interactions, whereas mobility of the non-conducting mutant decreased, similar to our previous observations on other membrane proteins in depolarized cells. At the IS formed with Raji B-cells, mobility of WT and non-conducting channels, unlike ΔC, was lower than outside the IS. The Kv1.3 variants possessing an intact C-terminus had lower mobility in standalone cells than in IS-engaged cells. This may be related to the observed segregation of F-actin into a ring-like structure at the periphery of the IS, leaving much of the cell almost void of F-actin. Upon depolarizing treatment, mobility of WT and ΔC channels decreased both in standalone and IS-engaged cells, contrary to non-conducting channels, which themselves caused depolarization. Our results support that Kv1.3 is enriched at the IS via its C-terminal region regardless of conductivity, and that depolarization decreases channel mobility.
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Affiliation(s)
- Veronika Sebestyén
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Éva Nagy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Gábor Mocsár
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Julianna Volkó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Orsolya Szilágyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Ádám Kenesei
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - György Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Katalin Tóth
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
- Division Biophysics of Macromolecules, German Cancer Research Center, D-69120 Heidelberg, Germany
| | - Péter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
- Department of Biophysics and Cell Biology, Faculty of Dentistry, University of Debrecen, H-4032 Debrecen, Hungary
- Correspondence: (P.H.); (G.V.)
| | - György Vámosi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
- Correspondence: (P.H.); (G.V.)
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Phan HTL, Kim HJ, Jo S, Kim WK, Namkung W, Nam JH. Anti-Inflammatory Effect of Licochalcone A via Regulation of ORAI1 and K + Channels in T-Lymphocytes. Int J Mol Sci 2021; 22:ijms221910847. [PMID: 34639190 PMCID: PMC8509259 DOI: 10.3390/ijms221910847] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/02/2021] [Accepted: 10/04/2021] [Indexed: 02/07/2023] Open
Abstract
Calcium signaling plays a vital role in the regulation of various cellular processes, including activation, proliferation, and differentiation of T-lymphocytes, which is mediated by ORAI1 and potassium (K+) channels. These channels have also been identified as highly attractive therapeutic targets for immune-related diseases. Licochalcone A is a licorice-derived chalconoid known for its multifaceted beneficial effects in pharmacological treatments, including its anti-inflammatory, anti-asthmatic, antioxidant, antimicrobial, and antitumorigenic properties. However, its anti-inflammatory effects involving ion channels in lymphocytes remain unclear. Thus, the present study aimed to investigate whether licochalcone A inhibits ORAI1 and K+ channels in T-lymphocytes. Our results indicated that licochalcone A suppressed all three channels (ORAI1, Kv1.3, and KCa3.1) in a concentration-dependent matter, with IC50 values of 2.97 ± 1.217 µM, 0.83 ± 1.222 µM, and 11.21 ± 1.07 µM, respectively. Of note, licochalcone A exerted its suppressive effects on the IL-2 secretion and proliferation in CD3 and CD28 antibody-induced T-cells. These results indicate that the use of licochalcone A may provide an effective treatment strategy for inflammation-related immune diseases.
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Affiliation(s)
- Hong T. L. Phan
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Korea; (H.J.K.); (W.K.K.)
| | - Hyun J. Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Korea; (H.J.K.); (W.K.K.)
| | - Sungwoo Jo
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, 85 Songdogwahak-ro, Incheon 21983, Korea;
| | - Woo K. Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Korea; (H.J.K.); (W.K.K.)
- Department of Internal Medicine Graduate School of Medicine, Dongguk University, 27 Dongguk-ro, Goyang 10326, Korea
| | - Wan Namkung
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, 85 Songdogwahak-ro, Incheon 21983, Korea;
- Correspondence: (W.N.); (J.H.N.)
| | - Joo H. Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Korea; (H.J.K.); (W.K.K.)
- Correspondence: (W.N.); (J.H.N.)
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Smallwood TB, Navarro S, Cristofori-Armstrong B, Watkins TS, Tungatt K, Ryan RYM, Haigh OL, Lutzky VP, Mulvenna JP, Rosengren KJ, Loukas A, Miles JJ, Clark RJ. Synthetic hookworm-derived peptides are potent modulators of primary human immune cell function that protect against experimental colitis in vivo. J Biol Chem 2021; 297:100834. [PMID: 34051231 PMCID: PMC8239465 DOI: 10.1016/j.jbc.2021.100834] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
The prevalence of autoimmune diseases is on the rise globally. Currently, autoimmunity presents in over 100 different forms and affects around 9% of the world's population. Current treatments available for autoimmune diseases are inadequate, expensive, and tend to focus on symptom management rather than cure. Clinical trials have shown that live helminthic therapy can decrease chronic inflammation associated with inflammatory bowel disease and other gastrointestinal autoimmune inflammatory conditions. As an alternative and better controlled approach to live infection, we have identified and characterized two peptides, Acan1 and Nak1, from the excretory/secretory component of parasitic hookworms for their therapeutic activity on experimental colitis. We synthesized Acan1 and Nak1 peptides from the Ancylostoma caninum and Necator americanus hookworms and assessed their structures and protective properties in human cell-based assays and in a mouse model of acute colitis. Acan1 and Nak1 displayed anticolitic properties via significantly reducing weight loss and colon atrophy, edema, ulceration, and necrosis in 2,4,6-trinitrobenzene sulfonic acid-exposed mice. These hookworm peptides prevented mucosal loss of goblet cells and preserved intestinal architecture. Acan1 upregulated genes responsible for the repair and restitution of ulcerated epithelium, whereas Nak1 downregulated genes responsible for epithelial cell migration and apoptotic cell signaling within the colon. These peptides were nontoxic and displayed key immunomodulatory functions in human peripheral blood mononuclear cells by suppressing CD4+ T cell proliferation and inhibiting IL-2 and TNF production. We conclude that Acan1 and Nak1 warrant further development as therapeutics for the treatment of autoimmunity, particularly gastrointestinal inflammatory conditions.
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Affiliation(s)
- Taylor B Smallwood
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, QLD, Australia
| | - Severine Navarro
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Woolworths Centre for Child Nutrition Research, Institute of Health and Biomedical Innovation, Queensland University of Technology, QLD, Australia
| | - Ben Cristofori-Armstrong
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, QLD, Australia
| | - Thomas S Watkins
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia
| | - Katie Tungatt
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, QLD, Australia
| | - Rachael Y M Ryan
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia
| | - Oscar L Haigh
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Viviana P Lutzky
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Jason P Mulvenna
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - K Johan Rosengren
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, QLD, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia
| | - John J Miles
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, QLD, Australia; Institute of Infection and Immunity, Cardiff University School of Medicine, University Hospital, Cardiff, Wales, United Kingdom.
| | - Richard J Clark
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, QLD, Australia.
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Capera J, Pérez-Verdaguer M, Peruzzo R, Navarro-Pérez M, Martínez-Pinna J, Alberola-Die A, Morales A, Leanza L, Szabó I, Felipe A. A novel mitochondrial Kv1.3-caveolin axis controls cell survival and apoptosis. eLife 2021; 10:e69099. [PMID: 34196606 PMCID: PMC8248986 DOI: 10.7554/elife.69099] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 06/22/2021] [Indexed: 12/16/2022] Open
Abstract
The voltage-gated potassium channel Kv1.3 plays an apparent dual physiological role by participating in activation and proliferation of leukocytes as well as promoting apoptosis in several types of tumor cells. Therefore, Kv1.3 is considered a potential pharmacological target for immunodeficiency and cancer. Different cellular locations of Kv1.3, at the plasma membrane or the mitochondria, could be responsible for such duality. While plasma membrane Kv1.3 facilitates proliferation, the mitochondrial channel modulates apoptotic signaling. Several molecular determinants of Kv1.3 drive the channel to the cell surface, but no information is available about its mitochondrial targeting. Caveolins, which are able to modulate cell survival, participate in the plasma membrane targeting of Kv1.3. The channel, via a caveolin-binding domain (CDB), associates with caveolin 1 (Cav1), which localizes Kv1.3 to lipid raft membrane microdomains. The aim of our study was to understand the role of such interactions not only for channel targeting but also for cell survival in mammalian cells. By using a caveolin association-deficient channel (Kv1.3 CDBless), we demonstrate here that while the Kv1.3-Cav1 interaction is responsible for the channel localization in the plasma membrane, a lack of such interaction accumulates Kv1.3 in the mitochondria. Kv1.3 CDBless severely affects mitochondrial physiology and cell survival, indicating that a functional link of Kv1.3 with Cav1 within the mitochondria modulates the pro-apoptotic effects of the channel. Therefore, the balance exerted by these two complementary mechanisms fine-tune the physiological role of Kv1.3 during cell survival or apoptosis. Our data highlight an unexpected role for the mitochondrial caveolin-Kv1.3 axis during cell survival and apoptosis.
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Affiliation(s)
- Jesusa Capera
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de BarcelonaBarcelonaSpain
| | - Mireia Pérez-Verdaguer
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de BarcelonaBarcelonaSpain
| | | | - María Navarro-Pérez
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de BarcelonaBarcelonaSpain
| | - Juan Martínez-Pinna
- Dept de Fisiología, Genética y Microbiología, Universidad de AlicanteAlicanteSpain
| | - Armando Alberola-Die
- Dept de Fisiología, Genética y Microbiología, Universidad de AlicanteAlicanteSpain
| | - Andrés Morales
- Dept de Fisiología, Genética y Microbiología, Universidad de AlicanteAlicanteSpain
| | - Luigi Leanza
- Department of Biology, University of PadovaPadovaItaly
| | - Ildiko Szabó
- Department of Biology, University of PadovaPadovaItaly
| | - Antonio Felipe
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de BarcelonaBarcelonaSpain
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9
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Macias A, de la Cruz A, Peraza DA, de Benito-Bueno A, Gonzalez T, Valenzuela C. K V1.5-K Vβ1.3 Recycling Is PKC-Dependent. Int J Mol Sci 2021; 22:ijms22031336. [PMID: 33572906 PMCID: PMC7866247 DOI: 10.3390/ijms22031336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/12/2021] [Accepted: 01/26/2021] [Indexed: 11/26/2022] Open
Abstract
KV1.5 channel function is modified by different regulatory subunits. KVβ1.3 subunits assemble with KV1.5 channels and induce a fast and incomplete inactivation. Inhibition of PKC abolishes the KVβ1.3-induced fast inactivation, decreases the amplitude of the current KV1.5–KVβ1.3 and modifies their pharmacology likely due to changes in the traffic of KV1.5–KVβ1.3 channels in a PKC-dependent manner. In order to analyze this hypothesis, HEK293 cells were transfected with KV1.5–KVβ1.3 channels, and currents were recorded by whole-cell configuration of the patch-clamp technique. The presence of KV1.5 in the membrane was analyzed by biotinylation techniques, live cell imaging and confocal microscopy approaches. PKC inhibition resulted in a decrease of 33 ± 7% of channels in the cell surface due to reduced recycling to the plasma membrane, as was confirmed by confocal microscopy. Live cell imaging indicated that PKC inhibition almost abolished the recycling of the KV1.5–KVβ1.3 channels, generating an accumulation of channels into the cytoplasm. All these results suggest that the trafficking regulation of KV1.5–KVβ1.3 channels is dependent on phosphorylation by PKC and, therefore, they could represent a clinically relevant issue, mainly in those diseases that exhibit modifications in PKC activity.
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Affiliation(s)
- Alvaro Macias
- Instituto de Investigaciones Biomédicas Madrid CSIC-UAM. C/Arturo Duperier 4, 28029 Madrid, Spain; (A.d.l.C.); (D.A.P.); (A.d.B.-B.); (T.G.)
- CIBER Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Correspondence: (A.M.); (C.V.); Tel.: +34-91-453-1200 (A.M.); +34-91-585-4493 (C.V.)
| | - Alicia de la Cruz
- Instituto de Investigaciones Biomédicas Madrid CSIC-UAM. C/Arturo Duperier 4, 28029 Madrid, Spain; (A.d.l.C.); (D.A.P.); (A.d.B.-B.); (T.G.)
| | - Diego A. Peraza
- Instituto de Investigaciones Biomédicas Madrid CSIC-UAM. C/Arturo Duperier 4, 28029 Madrid, Spain; (A.d.l.C.); (D.A.P.); (A.d.B.-B.); (T.G.)
- CIBER Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Angela de Benito-Bueno
- Instituto de Investigaciones Biomédicas Madrid CSIC-UAM. C/Arturo Duperier 4, 28029 Madrid, Spain; (A.d.l.C.); (D.A.P.); (A.d.B.-B.); (T.G.)
- CIBER Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Teresa Gonzalez
- Instituto de Investigaciones Biomédicas Madrid CSIC-UAM. C/Arturo Duperier 4, 28029 Madrid, Spain; (A.d.l.C.); (D.A.P.); (A.d.B.-B.); (T.G.)
- CIBER Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Department of Biochemistry, School of Medicine, Universidad Autónoma de Madrid, 28029 Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital Universitario La Paz (IdiPAZ), 28029 Madrid, Spain
| | - Carmen Valenzuela
- Instituto de Investigaciones Biomédicas Madrid CSIC-UAM. C/Arturo Duperier 4, 28029 Madrid, Spain; (A.d.l.C.); (D.A.P.); (A.d.B.-B.); (T.G.)
- CIBER Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Correspondence: (A.M.); (C.V.); Tel.: +34-91-453-1200 (A.M.); +34-91-585-4493 (C.V.)
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10
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Xie Z, Zhao Y, Yang W, Li W, Wu Y, Chen Z. Methotrexate, a small molecular scaffold targeting Kv1.3 channel extracellular pore region. Biochem Biophys Res Commun 2020; 532:265-270. [PMID: 32863001 DOI: 10.1016/j.bbrc.2020.08.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/14/2020] [Accepted: 08/18/2020] [Indexed: 11/18/2022]
Abstract
Methotrexate (MTX) has been widely used for the treatment of many types of autoimmune diseases, such as rheumatoid arthritis, psoriasis and dermatomyositis. However, its pharmacological mechanism is still unclear completely. In this study, we found that MTX is a potent and selective inhibitor of the Kv1.3 channel, a class of potassium channels highly associated with autoimmune diseases. Electrophysiological experiments showed that MTX inhibited human Kv1.3 channel with an IC50 of 41.5 ± 24.9 nM, and 1 μM MTX inhibited 32.6 ± 1.3% and 25.6 ± 2.2% of human Kv1.1 and Kv1.2 channel currents, respectively. These data implied the unique selectivity of MTX towards the Kv1.3 channel. Excitingly, using channel activation and chimeric experiments, we found that MTX bound to the outer pore region of Kv1.3 channel. Mutagenesis experiments in the Kv.3 channel extracellular pore region further showed that the Dsp371, Thr373 and His399 residues of outer pore region of Kv1.3 channel played important roles in MTX inhibiting activities. In conclusion, MTX inhibited Kv1.3 channel by targeting extracellular pore region, which is different form all the report small molecules, such as PAP-1 and 4-AP, but similar with many natural animal toxin peptides, such as ChTX, ShK and BmKTX. To the best of our knowledge, MTX is the first small molecular scaffold targeting the Kv1.3 channel extracellular pore region, suggesting its potential applications for designing novel Kv1.3 lead drugs and treating Kv1.3 channel-associated autoimmune diseases.
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Affiliation(s)
- Zili Xie
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yonghui Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Weishan Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China.
| | - Zongyun Chen
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China.
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11
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Solé L, Sastre D, Colomer-Molera M, Vallejo-Gracia A, Roig SR, Pérez-Verdaguer M, Lillo P, Tamkun MM, Felipe A. Functional Consequences of the Variable Stoichiometry of the Kv1.3-KCNE4 Complex. Cells 2020; 9:cells9051128. [PMID: 32370164 PMCID: PMC7290415 DOI: 10.3390/cells9051128] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 04/25/2020] [Accepted: 04/30/2020] [Indexed: 12/16/2022] Open
Abstract
The voltage-gated potassium channel Kv1.3 plays a crucial role during the immune response. The channel forms oligomeric complexes by associating with several modulatory subunits. KCNE4, one of the five members of the KCNE family, binds to Kv1.3, altering channel activity and membrane expression. The association of KCNEs with Kv channels is the subject of numerous studies, and the stoichiometry of such associations has led to an ongoing debate. The number of KCNE4 subunits that can interact and modulate Kv1.3 is unknown. KCNE4 transfers important elements to the Kv1.3 channelosome that negatively regulate channel function, thereby fine-tuning leukocyte physiology. The aim of this study was to determine the stoichiometry of the functional Kv1.3-KCNE4 complex. We demonstrate that as many as four KCNE4 subunits can bind to the same Kv1.3 channel, indicating a variable Kv1.3-KCNE4 stoichiometry. While increasing the number of KCNE4 subunits steadily slowed the activation of the channel and decreased the abundance of Kv1.3 at the cell surface, the presence of a single KCNE4 peptide was sufficient for the cooperative enhancement of the inactivating function of the channel. This variable architecture, which depends on KCNE4 availability, differentially affects Kv1.3 function. Therefore, our data indicate that the physiological remodeling of KCNE4 triggers functional consequences for Kv1.3, thus affecting cell physiology.
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Affiliation(s)
- Laura Solé
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (L.S.); (D.S.); (M.C.-M.); (A.V.-G.); (S.R.R.); (M.P.-V.)
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA;
| | - Daniel Sastre
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (L.S.); (D.S.); (M.C.-M.); (A.V.-G.); (S.R.R.); (M.P.-V.)
| | - Magalí Colomer-Molera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (L.S.); (D.S.); (M.C.-M.); (A.V.-G.); (S.R.R.); (M.P.-V.)
| | - Albert Vallejo-Gracia
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (L.S.); (D.S.); (M.C.-M.); (A.V.-G.); (S.R.R.); (M.P.-V.)
- Virology and Immunology, Gladstone Institutes, University of California San Francisco, San Francisco, CA 94158, USA
| | - Sara R. Roig
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (L.S.); (D.S.); (M.C.-M.); (A.V.-G.); (S.R.R.); (M.P.-V.)
- Imaging Core Facility, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
| | - Mireia Pérez-Verdaguer
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (L.S.); (D.S.); (M.C.-M.); (A.V.-G.); (S.R.R.); (M.P.-V.)
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Pilar Lillo
- Instituto de Química Física Rocasolano, CSIC, 28006 Madrid, Spain;
| | - Michael M. Tamkun
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA;
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (L.S.); (D.S.); (M.C.-M.); (A.V.-G.); (S.R.R.); (M.P.-V.)
- Correspondence: ; Tel.: +34-934034616; Fax: +34-934021559
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12
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Zhao R, Dai H, Mendelman N, Chill JH, Goldstein SAN. Tethered peptide neurotoxins display two blocking mechanisms in the K + channel pore as do their untethered analogs. Sci Adv 2020; 6:eaaz3439. [PMID: 32181366 PMCID: PMC7056315 DOI: 10.1126/sciadv.aaz3439] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
We show here that membrane-tethered toxins facilitate the biophysical study of the roles of toxin residues in K+ channel blockade to reveal two blocking mechanisms in the K+ channel pore. The structure of the sea anemone type I (SAK1) toxin HmK is determined by NMR. T-HmK residues are scanned by point mutation to map the toxin surface, and seven residues are identified to be critical to occlusion of the KcsA channel pore. T-HmK-Lys22 is shown to interact with K+ ions traversing the KcsA pore from the cytoplasm conferring voltage dependence on the toxin off rate, a classic mechanism that we observe as well with HmK in solution and for Kv1.3 channels. In contrast, two related SAK1 toxins, Hui1 and ShK, block KcsA and Kv1.3, respectively, via an arginine rather than the canonical lysine, when tethered and as free peptides.
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Affiliation(s)
- Ruiming Zhao
- Departments of Pediatrics and Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Hui Dai
- Departments of Pediatrics and Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Netanel Mendelman
- Department of Chemistry, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Jordan H. Chill
- Department of Chemistry, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Steve A. N. Goldstein
- Departments of Pediatrics and Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
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13
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Papp F, Hajdu P, Tajti G, Toth A, Nagy E, Fazekas Z, Kovacs S, Vámosi G, Varga Z, Panyi G. Periodic Membrane Potential and Ca 2+ Oscillations in T Cells Forming an Immune Synapse. Int J Mol Sci 2020; 21:ijms21051568. [PMID: 32106594 PMCID: PMC7084896 DOI: 10.3390/ijms21051568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/17/2020] [Accepted: 02/19/2020] [Indexed: 11/25/2022] Open
Abstract
The immunological synapse (IS) is a specialized contact area formed between a T cell and an antigen presenting cell (APC). Besides molecules directly involved in antigen recognition such as the TCR/CD3 complex, ion channels important in the membrane potential and intracellular free Ca2+ concentration control of T cells are also recruited into the IS. These are the voltage-gated Kv1.3 and Ca2+-activated KCa3.1 K+ channels and the calcium release-activated Ca2+ channel (CRAC). However, the consequence of this recruitment on membrane potential and Ca2+ level control is not known. Here we demonstrate that the membrane potential (MP) of murine T cells conjugated with APCs in an IS shows characteristic oscillations. We found that depolarization of the membrane by current injection or by increased extracellular K+ concentration produced membrane potential oscillations (MPO) significantly more frequently in conjugated T cells than in lone T cells. Furthermore, oscillation of the free intracellular Ca2+ concentration could also be observed more frequently in cells forming an IS than in lone cells. We suggest that in the IS the special arrangement of channels and the constrained space between the interacting cells creates a favorable environment for these oscillations, which may enhance the signaling process leading to T cell activation.
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Affiliation(s)
- Ferenc Papp
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (F.P.); (G.T.); (A.T.); (E.N.); (Z.F.); (G.V.); (Z.V.)
| | - Peter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Dentistry, University of Debrecen, H-4032 Debrecen, Hungary;
| | - Gabor Tajti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (F.P.); (G.T.); (A.T.); (E.N.); (Z.F.); (G.V.); (Z.V.)
| | - Agnes Toth
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (F.P.); (G.T.); (A.T.); (E.N.); (Z.F.); (G.V.); (Z.V.)
| | - Eva Nagy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (F.P.); (G.T.); (A.T.); (E.N.); (Z.F.); (G.V.); (Z.V.)
| | - Zsolt Fazekas
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (F.P.); (G.T.); (A.T.); (E.N.); (Z.F.); (G.V.); (Z.V.)
| | - Sandor Kovacs
- Institute of Sectoral Economics and Methodology, Faculty of Economics and Business, Department of Statistics and Research Methodology, University of Debrecen, 4032 Debrecen, Hungary;
| | - György Vámosi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (F.P.); (G.T.); (A.T.); (E.N.); (Z.F.); (G.V.); (Z.V.)
| | - Zoltan Varga
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (F.P.); (G.T.); (A.T.); (E.N.); (Z.F.); (G.V.); (Z.V.)
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (F.P.); (G.T.); (A.T.); (E.N.); (Z.F.); (G.V.); (Z.V.)
- Correspondence: ; Tel.: +36-52-258-603
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14
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Saito K, Abe N, Toyama H, Ejima Y, Yamauchi M, Mushiake H, Kazama I. Second-Generation Histamine H1 Receptor Antagonists Suppress Delayed Rectifier K +-Channel Currents in Murine Thymocytes. Biomed Res Int 2019; 2019:6261951. [PMID: 31183371 PMCID: PMC6515180 DOI: 10.1155/2019/6261951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/31/2019] [Accepted: 04/18/2019] [Indexed: 01/31/2023]
Abstract
BACKGROUND/AIMS Voltage-dependent potassium channels (Kv1.3) are predominantly expressed in lymphocyte plasma membranes. These channels are critical for the activation and proliferation of lymphocytes. Since second-generation antihistamines are lipophilic and exert immunomodulatory effects, they are thought to affect the lymphocyte Kv1.3-channel currents. METHODS Using the patch-clamp whole-cell recording technique in murine thymocytes, we tested the effects of second-generation antihistamines, such as cetirizine, fexofenadine, azelastine, and terfenadine, on the channel currents and the membrane capacitance. RESULTS These drugs suppressed the peak and the pulse-end currents of the channels, although the effects of azelastine and terfenadine on the peak currents were more marked than those of cetirizine and fexofenadine. Both azelastine and terfenadine significantly lowered the membrane capacitance. Since these drugs did not affect the process of endocytosis in lymphocytes, they were thought to have interacted directly with the plasma membranes. CONCLUSIONS Our study revealed for the first time that second-generation antihistamines, including cetirizine, fexofenadine, azelastine, and terfenadine, exert suppressive effects on lymphocyte Kv1.3-channels. The efficacy of these drugs may be related to their immunomodulatory mechanisms that reduce the synthesis of inflammatory cytokine.
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Affiliation(s)
- Kazutomo Saito
- Department of Anesthesiology, Tohoku University Hospital, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan
| | - Nozomu Abe
- Department of Anesthesiology, Tohoku University Hospital, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan
| | - Hiroaki Toyama
- Department of Anesthesiology, Tohoku University Hospital, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan
| | - Yutaka Ejima
- Department of Anesthesiology, Tohoku University Hospital, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan
| | - Masanori Yamauchi
- Department of Anesthesiology, Tohoku University Hospital, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan
| | - Hajime Mushiake
- Department of Physiology, Tohoku University Graduate School of Medicine, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan
| | - Itsuro Kazama
- Department of Physiology, Tohoku University Graduate School of Medicine, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan
- Miyagi University, School of Nursing, Gakuen, Taiwa-cho, Kurokawa-gun, Miyagi, Japan
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15
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Zhao Y, Xie Z, Feng J, Li W, Cao Z, Wu Y. Pharmacological characterization of human beta-defensins 3 and 4 on potassium channels: Evidence of diversity in beta-defensin-potassium channel interactions. Peptides 2018; 108:14-18. [PMID: 30121363 DOI: 10.1016/j.peptides.2018.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/12/2018] [Accepted: 08/13/2018] [Indexed: 12/28/2022]
Abstract
Recent reports have identified defensins as a new type of potassium channel inhibitors; differential binding mechanisms of human β-defensins hBD1 and hBD2 point to complex interactions between human β-defensins and potassium channels. We investigated the inhibitory effects of human defensins hBD3 and hBD4 on potassium channels. The data indicate that hBD3 is a voltage-gated channel subfamily A member 3 (Kv1.3) inhibitor with an IC50 value of 187.6 ± 25.7 nM; 1 μM hBD4 inhibited 34.0 ± 0.2% of Kv1.3 channel currents. Moreover, 1 μM hBD3 inhibited 50.6 ± 3.6% of Kv1.2 channel currents and had smaller effects on Kv1.1, SKCa3, and IKCa channel currents; these effects differed from the Kv1.3 channel-specific inhibitors hBD1 and hBD2. Similar to the pharmacological profiles of hBD1 and hBD2, hBD4 had lower inhibitory effects on Kv1.1, Kv1.2, SKCa3, and IKCa channels. Subsequent mutagenesis and channel activation experiments confirmed that hBD3 binds in a manner similar to that of hBD1, interacting with the outer pore region of the Kv1.3 channel without affecting Kv1.3 channel activation. Thus, the data indicate that the human β-defensin family is a novel group of potassium channel inhibitors with diverse types of human β-defensin-potassium channel interactions.
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Affiliation(s)
- Yonghui Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zili Xie
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jing Feng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; Biodrug Research Center, Wuhan University, Wuhan 430072, China
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; Biodrug Research Center, Wuhan University, Wuhan 430072, China
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; Biodrug Research Center, Wuhan University, Wuhan 430072, China.
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Lengyel M, Czirják G, Enyedi P. TRESK background potassium channel is not gated at the helix bundle crossing near the cytoplasmic end of the pore. PLoS One 2018; 13:e0197622. [PMID: 29763475 PMCID: PMC5953468 DOI: 10.1371/journal.pone.0197622] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/05/2018] [Indexed: 12/20/2022] Open
Abstract
Two-pore domain K+ channels (K2P) are responsible for background K+ currents and regulate the resting membrane potential and cellular excitability. Their activity is controlled by a large variety of physicochemical factors and intracellular signaling pathways. The majority of these effects converge on the intracellular C-terminus of the channels, resulting in the modification of the gating at the selectivity filter. Another gating mechanism, the activation gate at the helix bundle crossing is also well documented in other K+ channel families, however, it remains uncertain whether this type of gating is functional in K2P channels. The regulation of TWIK-related spinal cord K+ channel (TRESK) is different from the other K2P channels. Regulatory factors acting via the C-terminus are not known, instead channel activity is modified by the phosphorylation/dephosphorylation of the unusually long intracellular loop between the 2nd and 3rd transmembrane segments. These unique structural elements of the regulation lead us to examine channel gating at the bundle crossing region. Ba2+ was applied to the intracellular side of excised membrane patches and the characteristics of the channel block were determined. We compared the kinetics of the development of Ba2+ block when the channels were phosphorylated (inhibited) or dephosphorylated (activated) and also in different mutants mimicking the two functional states. Neither the phosphorylation/dephosphorylation nor the point mutations influenced the development of Ba2+ block, suggesting that the conformational changes of the bundle crossing region do not contribute to the phosphorylation-dependent gating of TRESK.
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Affiliation(s)
- Miklós Lengyel
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Gábor Czirják
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Péter Enyedi
- Department of Physiology, Semmelweis University, Budapest, Hungary
- * E-mail:
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Tyutyaev P, Grissmer S. Characterization of the σ-Pore in Mutant hKv1.3 Potassium Channels. Cell Physiol Biochem 2018; 46:1112-1121. [PMID: 29669325 DOI: 10.1159/000488840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 02/27/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The replacement of the amino acid valine at position 388 (Shaker position 438) in hKv1.3 channels or at the homologue position 370 in hKv1.2 channels resulted in a channel with two different ion conducting pathways: One pathway was the central, potassium-selective α-pore, that was sensitive to block by peptide toxins (CTX or KTX in the hKv1.3_V388C channel and CTX or MTX in the hKv1.2_V370C channel). The other pathway (σ-pore) was behind the central α-pore creating an inward current at potentials more negative than -100 mV, a potential range where the central α-pore was closed. In addition, current through the σ-pore could not be reduced by CTX, KTX or MTX in the hKv1.3_V388C or the hKv1.2_V370C channel, respectively. METHODS For a more detailed characterization of the σ-pore, we created a trimer consisting of three hKv1.3_V388C α-subunits linked together and characterized current through this trimeric hKv1.3_V388C channel. Additionally, we determined which amino acids line the σ-pore in the tetrameric hKv1.3_V388C channel by replacing single amino acids in the tetrameric hKv1.3_V388C mutant channel that could be involved in σ-pore formation. RESULTS Overexpression of the trimeric hKv1.3_V388C channel in COS-7 cells yielded typical σ-pore currents at potentials more negative than -100 mV similar to what was observed for the tetrameric hKv1.3_V388C channel. Electrophysiological properties of the trimeric and tetrameric channel were similar: currents could be observed at potentials more negative than -100 mV, were not carried by protons or chloride ions, and could not be reduced by peptide toxins (CTX, MTX) or TEA. The σ-pore was mostly permeable to Na+ and Li+. In addition, in our site-directed mutagenesis experiments, we created a number of new double mutant channels in the tetrameric hKv1.3_V388C background channel. Two of these tetrameric double mutant channels (hKv1.3_V388C_T392Y and hKv1.3_V388C_Y395W) did not show currents through the σ-pore. CONCLUSIONS From our experiments with the trimeric hKv1.3_V388C channel we conclude that the σ-pore exists in hKv1.3_V388C channels independently of the α-pore. From our site-directed mutagenesis experiments in the tetrameric hKv1.3_V388C channel we conclude that amino acid position 392 and 395 (Shaker position 442 and 445) line the σ-pore.
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Diesch AK, Grissmer S. Kinetic Aspects of Verapamil Binding (On-Rate) on Wild-Type and Six hKv1.3 Mutant Channels. Cell Physiol Biochem 2017; 44:172-184. [PMID: 29131061 DOI: 10.1159/000484625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/14/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The human-voltage gated Kv1.3 channel (hKv1.3) is expressed in T- and B lymphocytes. Verapamil is able to block hKv1.3 channels. We characterized the effect of verapamil on currents through hKv1.3 channels paying special attention to the on-rate (kon) of verapamil. By comparing on-rates obtained in wild-type (wt) and mutant channels a binding pocket for verapamil and impacts of different amino acid residues should be investigated. METHODS Using the whole-cell patch clamp technique the action of verapamil on currents through wild-type and six hKv1.3 mutant channels in the open state was investigated by measuring the time course of the open channel block in order to calculate kon of verapamil. RESULTS The on-rate of verapamil to block current through hKv1.3_T419C mutant channels is similar to that obtained for hKv1.3_wt channels whereas the on-rate of verapamil to block currents through hKv1.3_L417C and hKv1.3_L418C mutant channels was ∼ 3 times slower compared to in wt channels. The on-rate of verapamil to block currents through hKv1.3_L346C and the double mutant hKv1.3_L346C_L418C channel was ∼ 2 times slower compared to that obtained in the wt channel. The hKv1.3_I420C mutant channel reduced the on-rate of verapamil to block currents ∼ 6 fold. CONCLUSIONS We conclude that position 420 in hKv1.3 channels maximally interferes with verapamil reaching its binding site to block the channel. Positions 417 and 418 in hKv1.3 channels partially hinder verapamil reaching its binding site to block the channel whereas position 419 may not interfere with verapamil at all. Mutant hKv1.3_L346C and hKv1.3_L346C_L418C mutant channels might indirectly influence the ability of verapamil reaching its binding site to block current.
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Yan LJ, Yang HT, Duan HY, Wu JT, Fan XW, Wang SL, Qiu CG. Analysis on the relationship and mechanism of high blood pressure and vascular aging on the condition that the gender and age matches. Eur Rev Med Pharmacol Sci 2017; 21:84-87. [PMID: 28745785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
OBJECTIVE The relationship between hypertension and the mechanism of the expression of T-lymphocyte Kv1.3 channels in vascular aging has been analyzed in this study based on the gender and age matches' principle. PATIENTS AND METHODS Thirty patients have been consecutively chosen with vascular aging caused by hypertension (group A), while 30 cases of high blood pressure not merged with vascular aging (group B) were chosen, and 30 cases of healthy volunteers (group C), conforming to gender and age 1:1 and the closest matching principle, were studied. The aim of this study was to separate the peripheral blood mononuclear cells and give intervention of 0.2 nmol/L ANGII to CD4 + T-lymphocytes, and store them in the incubator 48 h. The difference of Kv1.3 channel current of CD4 + T-lymphocyte, mRNA, angiotensin receptor (AT1R) protein mRNA, and IFN-γ density has also been compared. RESULTS The membrane capacitance, peak current, and current density of group A, are higher than those of the other two groups, and the differences have statistical significance (p<0.05). After adding ANGII intervention to group A, the expression levels of T-lymphocyte Kv1.3 potassium channels mRNA, AT1R mRNA, and IFN-γ are significantly increased, so that the difference has statistical significance p<0.05, while the other two groups have no significant change (p>0.05). The levels of Kv1.3 potassium channels, AT1R mRNA, and IFN-γ of group A before and after the intervention are significantly higher than those of the other two groups, and the differences are statistically significant (p<0.05). CONCLUSIONS Vascular aging caused by hypertension may be linked to the increase of Kv1.3 potassium channel activity of T-lymphocyte, while ANGII can improve the high expression of Kv1.3 potassium channel and AT1R, to stimulate lymph cells to secrete IFN-γ.
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Affiliation(s)
- L-J Yan
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
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Leanza L, Romio M, Becker KA, Azzolini M, Trentin L, Managò A, Venturini E, Zaccagnino A, Mattarei A, Carraretto L, Urbani A, Kadow S, Biasutto L, Martini V, Severin F, Peruzzo R, Trimarco V, Egberts JH, Hauser C, Visentin A, Semenzato G, Kalthoff H, Zoratti M, Gulbins E, Paradisi C, Szabo I. Direct Pharmacological Targeting of a Mitochondrial Ion Channel Selectively Kills Tumor Cells In Vivo. Cancer Cell 2017; 31:516-531.e10. [PMID: 28399409 DOI: 10.1016/j.ccell.2017.03.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 02/03/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Abstract
The potassium channel Kv1.3 is highly expressed in the mitochondria of various cancerous cells. Here we show that direct inhibition of Kv1.3 using two mitochondria-targeted inhibitors alters mitochondrial function and leads to reactive oxygen species (ROS)-mediated death of even chemoresistant cells independently of p53 status. These inhibitors killed 98% of ex vivo primary chronic B-lymphocytic leukemia tumor cells while sparing healthy B cells. In orthotopic mouse models of melanoma and pancreatic ductal adenocarcinoma, the compounds reduced tumor size by more than 90% and 60%, respectively, while sparing immune and cardiac functions. Our work provides direct evidence that specific pharmacological targeting of a mitochondrial potassium channel can lead to ROS-mediated selective apoptosis of cancer cells in vivo, without causing significant side effects.
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Affiliation(s)
- Luigi Leanza
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Matteo Romio
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy
| | - Katrin Anne Becker
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Michele Azzolini
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Livio Trentin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Antonella Managò
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Elisa Venturini
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Angela Zaccagnino
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Andrea Mattarei
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy
| | - Luca Carraretto
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Andrea Urbani
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Stephanie Kadow
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Lucia Biasutto
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Veronica Martini
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Filippo Severin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Roberta Peruzzo
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Valentina Trimarco
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Jan-Hendrik Egberts
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Charlotte Hauser
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Andrea Visentin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Gianpietro Semenzato
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Holger Kalthoff
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Mario Zoratti
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany; Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0558, USA.
| | - Cristina Paradisi
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy.
| | - Ildiko Szabo
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy.
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He T, Wang C, Zhang M, Zhang X, Zheng S, Linghu E, Guo M. Epigenetic regulation of voltage-gated potassium ion channel molecule Kv1.3 in mechanisms of colorectal cancer. Discov Med 2017; 23:155-162. [PMID: 28472608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Colorectal cancer (CRC) is among the leading causes of cancer-related death throughout the world. Aberrant expression of voltage-gated potassium ion channel molecule Kv1.3 has been reported in various cancers. To explore the expression and regulation of Kv1.3 in colorectal cancer, 7 colorectal cancer cell lines and 147 cases of primary colorectal cancer were involved in this study. Kv1.3 was expressed in LOVO and SW480 cells and loss of expression was found in RKO, DLD1, SW620, HCT116, and HT29 cells. Complete methylation was found in RKO, DLD1, SW620, HCT116, and HT29 cells, partial methylation was found in LOVO and SW480 cells. Loss of/reduced expression of Kv1.3 is correlated with methylation of its promoter region. The expression of Kv1.3 was restored in RKO, DLD1, SW620, HCT116, and HT29 cells, and increased in LOVO and SW480 cells after 5-aza-2'-deoxycytidine (DAC) treatment. The results suggest that the expression of Kv1.3 is regulated by the gene's promoter region methylation in human CRC cells. Kv1.3 was methylated in 76.19% (112/147) of primary human colorectal cancer. Methylation of Kv1.3 is associated with age, tumor differentiation, and poor 5-year survival. In conclusion, Kv1.3 is frequently methylated in human colorectal cancer and the expression of Kv1.3 is regulated by its promoter region methylation. Kv1.3 methylation may serve as diagnostic and prognostic markers in colorectal cancer.
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Affiliation(s)
- Tao He
- Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing 100853, China
- Department of Pathology, The Affiliated Hospital of Logistics University of Chinese People's Armed Police Force, Tianjin 300162, China
- These authors contributed equally to this article
| | - Can Wang
- Department of Clinical Biochemistry, Chinese PLA General Hospital, Beijing 100853, China
- These authors contributed equally to this article
| | - Meiying Zhang
- Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing 100853, China
| | - Xiaomei Zhang
- Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing 100853, China
| | - Shufang Zheng
- Department of Pathology, The Affiliated Hospital of Logistics University of Chinese People's Armed Police Force, Tianjin 300162, China
| | - Enqiang Linghu
- Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing 100853, China
| | - Mingzhou Guo
- Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing 100853, China
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Fung-Leung WP, Edwards W, Liu Y, Ngo K, Angsana J, Castro G, Wu N, Liu X, Swanson RV, Wickenden AD. T Cell Subset and Stimulation Strength-Dependent Modulation of T Cell Activation by Kv1.3 Blockers. PLoS One 2017; 12:e0170102. [PMID: 28107393 PMCID: PMC5249144 DOI: 10.1371/journal.pone.0170102] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 12/29/2016] [Indexed: 12/28/2022] Open
Abstract
Kv1.3 is a voltage-gated potassium channel expressed on T cells that plays an important role in T cell activation. Previous studies have shown that blocking Kv1.3 channels in human T cells during activation results in reduced calcium entry, cytokine production, and proliferation. The aim of the present study was to further explore the effects of Kv1.3 blockers on the response of different human T cell subsets under various stimulation conditions. Our studies show that, unlike the immune suppressor cyclosporine A, the inhibitory effect of Kv1.3 blockers was partial and stimulation strength dependent, with reduced inhibitory efficacy on T cells under strengthened anti-CD3/CD28 stimulations. T cell responses to allergens including house dust mites and ragweed were partially reduced by Kv1.3 blockers. The effect of Kv1.3 inhibition was dependent on T cell subsets, with stronger effects on CCR7- effector memory compared to CCR7+ central memory CD4 T cells. Calcium entry studies also revealed a population of CD4 T cells resistant to Kv1.3 blockade. Activation of CD4 T cells was accompanied with an increase in Kv1.3 currents but Kv1.3 transcripts were found to be reduced, suggesting a posttranscriptional mechanism in the regulation of Kv1.3 activities. In summary, Kv1.3 blockers inhibit T cell activation in a manner that is highly dependent on the T cell identity and stimulation strength, These findings suggest that Kv1.3 blockers inhibit T cells in a unique, conditional manner, further refining our understanding of the therapeutic potential of Kv1.3 blockers.
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Affiliation(s)
- Wai-Ping Fung-Leung
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
- * E-mail:
| | - Wilson Edwards
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
| | - Yi Liu
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
| | - Karen Ngo
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
| | - Julianty Angsana
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
| | - Glenda Castro
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
| | - Nancy Wu
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
| | - Xuejun Liu
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
| | - Ronald V. Swanson
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
| | - Alan D. Wickenden
- Janssen Research & Development, L.L.C., San Diego, California, United States of America
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Huang SS, Zhang QB, Yuan QY, He SL, Zhang YM. Inhibitory effects of telmisartan on culture and proliferation of and Kv1.3 potassium channel expression in peripheral blood CD4+ T lymphocytes from Xinjiang Kazakh patients with hypertension. J Renin Angiotensin Aldosterone Syst 2016; 17:1470320316674876. [PMID: 27765883 PMCID: PMC5843919 DOI: 10.1177/1470320316674876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/16/2016] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION Activation of T lymphocytes, for which potassium channels are essential, is involved in the development of hypertension. In this study, we explored the inhibitory effects of telmisartan on the culture and proliferation of and Kv1.3 potassium channel expression in peripheral blood CD4+ T lymphocytes derived from Xinjiang Kazakh patients with hypertension. METHODS CD4+ T-cell samples from hypertensive Kazakh patients and healthy Kazakh people were divided into healthy control, case control, telmisartan, and 4-aminopytidine groups. Changes in the expression levels of interleukin (IL)-6 and IL-17 in the blood of the healthy control and case control subjects were detected by enzyme-linked immunosorbent assay. Peripheral blood CD4+ T lymphocytes were first activated and proliferated in vitro and then incubated for 0, 24, and 48 h under various treatment conditions. Thereafter, changes in CD4+ T-lymphocytic proliferation were determined using Cell Counting Kit-8 and microscope photography. Changes in messenger RNA (mRNA) and protein expression of the Kv1.3 potassium channel in CD4+ T lymphocytes were detected using real-time quantitative polymerase chain reaction and Western blots, respectively. RESULTS The IL-6 and IL-17 expression levels were significantly higher in the blood of the hypertensive Kazakh patients than in the healthy Kazakh people. Telmisartan inhibited T-lymphocytic proliferation, as well as the mRNA and protein expression of the Kv1.3 potassium channel in CD4+ T lymphocytes, and the inhibitory effects were time-dependent, with the strongest inhibition observed after 48 h and significantly weaker inhibition observed after 24 h of treatment. CONCLUSIONS Telmisartan may potentially regulate hypertensive inflammatory responses by inhibiting T-lymphocytic proliferation and Kv1.3 potassium channel expression in CD4+ T lymphocytes.
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Affiliation(s)
- Sha-Sha Huang
- Heart Centre, First Affiliated Hospital of Xinjiang Medical University, China
| | - Qiu-Bing Zhang
- Heart Centre, First Affiliated Hospital of Xinjiang Medical University, China
| | - Qing-Yan Yuan
- Heart Centre, First Affiliated Hospital of Xinjiang Medical University, China
| | - Si-Li He
- Heart Centre, First Affiliated Hospital of Xinjiang Medical University, China
| | - Yuan-Ming Zhang
- Heart Centre, First Affiliated Hospital of Xinjiang Medical University, China
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Reeves TM, Trimmer PA, Colley BS, Phillips LL. Targeting Kv1.3 channels to reduce white matter pathology after traumatic brain injury. Exp Neurol 2016; 283:188-203. [PMID: 27302680 DOI: 10.1016/j.expneurol.2016.06.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/31/2016] [Accepted: 06/10/2016] [Indexed: 02/07/2023]
Abstract
Axonal injury is present in essentially all clinically significant cases of traumatic brain injury (TBI). While no effective treatment has been identified to date, experimental TBI models have shown promising axonal protection using immunosuppressants FK506 and Cyclosporine-A, with treatment benefits attributed to calcineurin inhibition or protection of mitochondrial function. However, growing evidence suggests neuroprotective efficacy of these compounds may also involve direct modulation of ion channels, and in particular Kv1.3. The present study tested whether blockade of Kv1.3 channels, using Clofazimine (CFZ), would alleviate TBI-induced white matter pathology in rodents. Postinjury CFZ administration prevented suppression of compound action potential (CAP) amplitude in the corpus callosum of adult rats following midline fluid percussion TBI, with injury and treatment effects primarily expressed in unmyelinated CAPs. Kv1.3 protein levels in callosal tissue extracts were significantly reduced postinjury, but this loss was prevented by CFZ treatment. In parallel, CFZ also attenuated the injury-induced elevation in pro-inflammatory cytokine IL1-β. The effects of CFZ on glial function were further studied using mixed microglia/astrocyte cell cultures derived from P3-5 mouse corpus callosum. Cultures of callosal glia challenged with lipopolysaccharide exhibited a dramatic increase in IL1-β levels, accompanied by reactive morphological changes in microglia, both of which were attenuated by CFZ treatment. These results support a cell specific role for Kv1.3 signaling in white matter pathology after TBI, and suggest a treatment approach based on the blockade of these channels. This therapeutic strategy may be especially efficacious for normalizing neuro-glial interactions affecting unmyelinated axons after TBI.
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Affiliation(s)
- Thomas M Reeves
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Patricia A Trimmer
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Beverly S Colley
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Linda L Phillips
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
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Yan L, Liu X, Liu WX, Tan XQ, Xiong F, Gu N, Hao W, Gao X, Cao JM. Fe2O3 nanoparticles suppress Kv1.3 channels via affecting the redox activity of Kvβ2 subunit in Jurkat T cells. Nanotechnology 2015; 26:505103. [PMID: 26584910 DOI: 10.1088/0957-4484/26/50/505103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Superparamagnetic iron oxide nanoparticles (SPIONs) are promising nanomaterials in medical practice due to their special magnetic characteristics and nanoscale size. However, their potential impacts on immune cells are not well documented. This study aims to investigate the effects of Fe2O3 nanoparticles (Fe2O3-NPs) on the electrophysiology of Kv1.3 channels in Jurkat T cells. Using the whole-cell patch-clamp technique, we demonstrate that incubation of Jurkat cells with Fe2O3-NPs dose- and time-dependently decreased the current density and shifted the steady-state inactivation curve and the recovery curve of Kv1.3 channels to a rightward direction. Fe2O3-NPs increased the NADP level but decreased the NADPH level of Jurkat cells. Direct induction of NADPH into the cytosole of Jurkat cells via the pipette abolished the rightward shift of the inactivation curve. In addition, transmission electron microscopy showed that Fe2O3-NPs could be endocytosed by Jurkat cells with relatively low speed and capacity. Fe2O3-NPs did not significantly affect the viability of Jurkat cells, but suppressed the expressions of certain cytokines (TNFα, IFNγ and IL-2) and interferon responsive genes (IRF-1 and PIM-1), and the time courses of Fe2O3-NPs endocytosis and effects on the expressions of cytokines and interferon responsive genes were compatible. We conclude that Fe2O3-NPs can be endocytosed by Jurkat cells and act intracellularly. Fe2O3-NPs decrease the current density and delay the inactivation and recovery kinetics of Kv1.3 channels in Jurkat cells by oxidizing NADPH and therefore disrupting the redox activity of the Kvβ2 auxiliary subunit, and as a result, lead to changes of the Kv1.3 channel function. These results suggest that iron oxide nanoparticles may affect T cell function by disturbing the activity of Kv1.3 channels. Further, the suppressing effects of Fe2O3-NPs on the expressions of certain inflammatory cytokines and interferon responsive genes suggest that iron oxide nanoparticles may exert modulatory effects on T cell immune activities and anti-inflammation effects.
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Affiliation(s)
- Li Yan
- Department of Pathophysiology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, People's Republic of China
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Warsi J, Fezai M, Fores M, Elvira B, Lang F. Up-Regulation of Voltage Gated K+ Channels Kv1.3 and Kv1.5 by Protein Kinase PKB/Akt. Cell Physiol Biochem 2015; 37:2454-63. [PMID: 26666245 DOI: 10.1159/000438598] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The voltage gated K+ channels Kv1.3 and Kv1.5 contribute to the orchestration of cell proliferation. Kinases participating in the regulation of cell proliferation include protein kinase B (PKB/Akt). The present study thus explored whether PKB/Akt modifies the abundance and function of Kv1.3 and Kv1.5. METHODS Kv1.3 or Kv1.5 was expressed in Xenopus laevis oocytes with or without wild-type PKB/Akt, constitutively active T308D/S473DPKB/Akt or inactive T308A/S473APKB/Akt. The channel activity was quantified utilizing dual electrode voltage clamp. Moreover, HA-tagged Kv1.5 protein was determined utilizing chemiluminescence. RESULTS Voltage gated K+ currents were observed in Kv1.3 or Kv1.5 expressing oocytes but not in water-injected oocytes or in oocytes expressing PKB/Akt alone. Co-expression of PKB/Akt or T308D/S473DPKB/Akt, but not co-expression of T308A/S473APKB/Akt significantly increased the voltage gated current in both Kv1.3 and Kv1.5 expressing oocytes. As shown for Kv1.5, co-expression of PKB/Akt enhanced the channel protein abundance in the cell membrane. In Kv1.5 expressing oocytes voltage gated current decreased following inhibition of carrier insertion by brefeldin A (5 µM) to similarly low values in the absence and presence of PKB/Akt, suggesting that PKB/Akt stimulated carrier insertion into rather than inhibiting carrier retrieval from the cell membrane. CONCLUSION PKB/Akt up-regulates both, Kv1.3 and Kv1.5 K+ channels.
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Zhu H, Yan L, Gu J, Hao W, Cao J. Kv1.3 channel blockade enhances the phagocytic function of RAW264.7 macrophages. Sci China Life Sci 2015; 58:867-75. [PMID: 26354506 DOI: 10.1007/s11427-015-4915-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/13/2015] [Indexed: 11/25/2022]
Abstract
This study aimed to comprehend the largely unknown role of voltage-gated potassium channel 1.3 (Kv1.3) in the phagocytic function of macrophages. We found that blocking of the Kv1.3 channel with 100 pmol L(-1) Stichodactyla helianthus neurotoxin (ShK) enhanced the phagocytic capacities of both resting and lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages in the chicken erythrocyte system. In the fluorescein isothiocyanate (FITC)-labeled Escherichia coli k-12 system, ShK increased the phagocytic capacities of resting RAW264.7 cells, but not of the LPS-stimulated cells, as LPS alone stimulated almost saturated phagocytosis of the macrophages. ShK increased the nitric oxide (NO) production in LPS-activated cells, but not in resting RAW264.7 cells. There was no effect of ShK alone on the cytokine secretions in resting RAW264.7 cells, but it suppressed IL-1β secretion in LPS-stimulated RAW264.7 cells. At a concentration of 100 pmol L(-1), ShK did not affect the viability of the tested cells. Kv1.3 was expressed in RAW264.7 cells; this expression was downregulated by LPS, but significantly upregulated by disrupting caveolin-dependent endocytosis with filipin III. In addition, cytochalasin D, an inhibitor of actin polymerization, did not affect the Kv1.3 expression. Thus, blocking of the Kv1.3 channel enhances the phagocytic capacity and NO production of this cell line. Our results suggest that Kv1.3 channel serves as a negative regulator of phagocytosis in macrophages and can therefore be a potential target in the treatment of macrophage dysfunction.
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Affiliation(s)
- Hong Zhu
- Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine Peking, Union Medical College, Beijing, 100005, China
| | - Li Yan
- Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - JingLi Gu
- Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine Peking, Union Medical College, Beijing, 100005, China
| | - Wei Hao
- Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine Peking, Union Medical College, Beijing, 100005, China
| | - JiMin Cao
- Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine Peking, Union Medical College, Beijing, 100005, China.
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Gąsiorowska J, Teisseyre A, Uryga A, Michalak K. Inhibition of Kv1.3 Channels in Human Jurkat T Cells by Xanthohumol and Isoxanthohumol. J Membr Biol 2015; 248:705-11. [PMID: 25688010 PMCID: PMC4513206 DOI: 10.1007/s00232-015-9782-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 07/15/2014] [Indexed: 01/05/2023]
Abstract
Using whole-cell patch-clamp technique, we investigated influence of selected compounds from groups of prenylated chalcones and flavonoids: xanthohumol and isoxanthohumol on the activity of Kv1.3 channels in human leukemic Jurkat T cells. Obtained results provide evidence that both examined compounds were inhibitors of Kv1.3 channels in these cells. The inhibitory effects occurred in a concentration-dependent manner. The estimated value of the half-blocking concentration (EC50) was about 3 μM for xanthohumol and about 7.8 μM for isoxanthohumol. The inhibition of Kv1.3 channels by examined compounds was not complete. Upon an application of the compounds at the maximal concentrations equal to 30 μM, the activity of Kv1.3 channels was inhibited to about 0.13 of the control value. The inhibitory effect was reversible. The application of xanthohumol and isoxanthohumol did not change the currents' activation and inactivation rate. These results may confirm our earlier hypothesis that the presence of a prenyl group in a molecule is a factor that facilitates the inhibition of Kv1.3 channels by compounds from the groups of flavonoids and chalcones. The inhibition of Kv1.3 channels might be involved in antiproliferative and proapoptotic effects of the compounds observed in cancer cell lines expressing these channels.
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Affiliation(s)
- Justyna Gąsiorowska
- Department of Biophysics, Wroclaw Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland
| | - Andrzej Teisseyre
- Department of Biophysics, Wroclaw Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland
| | - Anna Uryga
- Department of Biophysics, Wroclaw Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland
| | - Krystyna Michalak
- Department of Biophysics, Wroclaw Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Charolidi N, Schilling T, Eder C. Microglial Kv1.3 Channels and P2Y12 Receptors Differentially Regulate Cytokine and Chemokine Release from Brain Slices of Young Adult and Aged Mice. PLoS One 2015; 10:e0128463. [PMID: 26011191 PMCID: PMC4444306 DOI: 10.1371/journal.pone.0128463] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 04/27/2015] [Indexed: 01/08/2023] Open
Abstract
Brain tissue damage following stroke or traumatic brain injury is accompanied by neuroinflammatory processes, while microglia play a central role in causing and regulating neuroinflammation via production of proinflammatory substances, including cytokines and chemokines. Here, we used brain slices, an established in situ brain injury model, from young adult and aged mice to investigate cytokine and chemokine production with particular focus on the role of microglia. Twenty four hours after slice preparation, higher concentrations of proinflammatory cytokines, i.e. TNF-α and IL-6, and chemokines, i.e. CCL2 and CXCL1, were released from brain slices of aged mice than from slices of young adult mice. However, maximal microglial stimulation with LPS for 24 h did not reveal age-dependent differences in the amounts of released cytokines and chemokines. Mechanisms underlying microglial cytokine and chemokine production appear to be similar in young adult and aged mice. Inhibition of microglial Kv1.3 channels with margatoxin reduced release of IL-6, but not release of CCL2 and CXCL1. In contrast, blockade of microglial P2Y12 receptors with PSB0739 inhibited release of CCL2 and CXCL1, whereas release of IL-6 remained unaffected. Cytokine and chemokine production was not reduced by inhibitors of Kir2.1 K+ channels or adenosine receptors. In summary, our data suggest that brain tissue damage-induced production of cytokines and chemokines is age-dependent, and differentially regulated by microglial Kv1.3 channels and P2Y12 receptors.
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Affiliation(s)
- Nicoletta Charolidi
- Institute for Infection and Immunity; St. George’s, University of London; Cranmer Terrace; London SW17 0RE, United Kingdom
| | - Tom Schilling
- Institute for Infection and Immunity; St. George’s, University of London; Cranmer Terrace; London SW17 0RE, United Kingdom
| | - Claudia Eder
- Institute for Infection and Immunity; St. George’s, University of London; Cranmer Terrace; London SW17 0RE, United Kingdom
- * E-mail:
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Jang SH, Byun JK, Jeon WI, Choi SY, Park J, Lee BH, Yang JE, Park JB, O'Grady SM, Kim DY, Ryu PD, Joo SW, Lee SY. Nuclear localization and functional characteristics of voltage-gated potassium channel Kv1.3. J Biol Chem 2015; 290:12547-57. [PMID: 25829491 PMCID: PMC4432276 DOI: 10.1074/jbc.m114.561324] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/26/2015] [Indexed: 12/29/2022] Open
Abstract
It is widely known that ion channels are expressed in the plasma membrane. However, a few studies have suggested that several ion channels including voltage-gated K(+) (Kv) channels also exist in intracellular organelles where they are involved in the biochemical events associated with cell signaling. In the present study, Western blot analysis using fractionated protein clearly indicates that Kv1.3 channels are expressed in the nuclei of MCF7, A549, and SNU-484 cancer cells and human brain tissues. In addition, Kv1.3 is located in the plasma membrane and the nucleus of Jurkat T cells. Nuclear membrane hyperpolarization after treatment with margatoxin (MgTX), a specific blocker of Kv1.3 channels, provides evidence for functional channels at the nuclear membrane of A549 cells. MgTX-induced hyperpolarization is abolished in the nuclei of Kv1.3 silenced cells, and the effects of MgTX are dependent on the magnitude of the K(+) gradient across the nuclear membrane. Selective Kv1.3 blockers induce the phosphorylation of cAMP response element-binding protein (CREB) and c-Fos activation. Moreover, Kv1.3 is shown to form a complex with the upstream binding factor 1 in the nucleus. Chromatin immunoprecipitation assay reveals that Sp1 transcription factor is directly bound to the promoter region of the Kv1.3 gene, and the Sp1 regulates Kv1.3 expression in the nucleus of A549 cells. These results demonstrate that Kv1.3 channels are primarily localized in the nucleus of several types of cancer cells and human brain tissues where they are capable of regulating nuclear membrane potential and activation of transcription factors, such as phosphorylated CREB and c-Fos.
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Affiliation(s)
- Soo Hwa Jang
- From the Laboratories of Veterinary Pharmacology and the Biomedical Research Center, School of Biological Sciences, University of Ulsan, Ulsan 680-749, Korea
| | - Jun Kyu Byun
- From the Laboratories of Veterinary Pharmacology and
| | - Won-Il Jeon
- From the Laboratories of Veterinary Pharmacology and
| | | | - Jin Park
- the Department of Chemistry, Soongsil University, Seoul 156-743, Korea
| | - Bo Hyung Lee
- From the Laboratories of Veterinary Pharmacology and
| | - Ji Eun Yang
- From the Laboratories of Veterinary Pharmacology and
| | - Jin Bong Park
- the Department of Physiology, School of Medicine, Chungnam National University, Daejeon 305-764, Korea, and
| | - Scott M O'Grady
- the Department of Animal Science and Integrative Biology and Physiology, University of Minnesota, St. Paul, Minnesota 55455
| | - Dae-Yong Kim
- Veterinary Pathology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea
| | - Pan Dong Ryu
- From the Laboratories of Veterinary Pharmacology and
| | - Sang-Woo Joo
- the Department of Chemistry, Soongsil University, Seoul 156-743, Korea
| | - So Yeong Lee
- From the Laboratories of Veterinary Pharmacology and
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Teisseyre A, Gąsiorowska J, Michalak K. Voltage-Gated Potassium Channels Kv1.3--Potentially New Molecular Target in Cancer Diagnostics and Therapy. ADV CLIN EXP MED 2015; 24:517-24. [PMID: 26467143 DOI: 10.17219/acem/22339] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Voltage-gated potassium channels, Kv1.3, which were discovered in 1984, are integral membrane proteins which are activated ("open") upon change of the cell membrane potential, enabling a passive flux of potassium ions across the cell membrane. The channels are expressed in many different tissues, both normal and cancer. Since 2005 it has been known that the channels are expressed not only in the plasma membrane, but also in the inner mitochondrial membrane. The activity of Kv1.3 channels plays an important role, among others, in setting the cell resting membrane potential, cell proliferation, apoptosis and volume regulation. For some years, these channels have been considered a potentially new molecular target in both the diagnostics and therapy of some cancer diseases. This review article focuses on: 1) changes of expression of the channels in cancer disorders with special regard to correlations between the channels' expression and stage of the disease, 2) influence of inhibitors of Kv1.3 channels on proliferation and apoptosis of cancer cells, 3) possible future applications of Kv1.3 channels' inhibitors in therapy of some cancer diseases. In the last section, the results of studies performed in our Laboratory of Bioelectricity on the influence of selected biologically active plant-derived compounds from the groups of flavonoids and stilbenes and their natural and synthetic derivatives on the activity of Kv1.3 channels in normal and cancer cells are reviewed. A possible application of some compounds from these groups to support therapy of cancer diseases, such as breast, colon and lymph node cancer, and melanoma or chronic lymphocytic leukemia (B-CLL), is announced.
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Kazama I. Physiological significance of delayed rectifier K(+) channels (Kv1.3) expressed in T lymphocytes and their pathological significance in chronic kidney disease. J Physiol Sci 2015; 65:25-35. [PMID: 25096892 PMCID: PMC10717717 DOI: 10.1007/s12576-014-0331-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/14/2014] [Indexed: 11/24/2022]
Abstract
T lymphocytes predominantly express delayed rectifier K(+) channels (Kv1.3) in their plasma membranes. More than 30 years ago, patch-clamp studies revealed that the channels play crucial roles in facilitating the calcium influx necessary to trigger lymphocyte activation and proliferation. In addition to selective channel inhibitors that have been developed, we recently showed physiological evidence that drugs such as nonsteroidal anti-inflammatory drugs, antibiotics, and anti-hypertensives effectively suppress the channel currents in lymphocytes, and thus exert immunosuppressive effects. Using experimental animal models, previous studies revealed the pathological relevance between the expression of ion channels and the progression of renal diseases. As an extension, we recently demonstrated that the overexpression of lymphocyte Kv1.3 channels contributed to the progression of chronic kidney disease (CKD) by promoting cellular proliferation and interstitial fibrosis. Together with our in-vitro results, the studies indicated the therapeutic potency of Kv1.3-channel inhibitors in the treatment or the prevention of CKD.
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Affiliation(s)
- Itsuro Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan,
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34
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Hansen LK. The role of T cell potassium channels, KV1.3 and KCa3.1, in the inflammatory cascade in ulcerative colitis. Dan Med J 2014; 61:B4946. [PMID: 25370966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ulcerative Colitis (UC) is a chronic inflammatory bowel disease located in the mucosa of the large bowel. UC often affects young adults between 15 and 40 years of age with no pre-dominant sex. Over time, incidence rates are steadily increasing and the cause of the disease remains unknown. Symptoms are general discomfort and bloody diarrhea. UC is diagnosed by endoscopic examination of the large bowel, where different hallmarks are found. It is of great importance that attacks/relapses are treated medically, as flares may cause death due to inflammatory destruction of the mucosa and perforation of the colon leading to extreme infection of the abdominal cavity. UC often affects the social life of the patients, as they feel that they must be in the immediate vicinity of toilets. Therefore, many patients prefer to stay at home during active disease. For society, UC is a costly disease due to patients reporting in sick and expensive medications. When medical treatment fails, UC patients must undergo surgery and have their colon removed (colectomy). This PhD project focused on the immune system of the body. Specifically, we looked into T cells (the chairmen of the immune system) that we believe play an important role in disease activity. When T cells are activated in inflammatory diseases, they produce several signaling substances (cytokines) that attract and activate the other parts of the immune system. T cells regulate their effector functions through calcium regulation. Upon activation, calcium is released from intracellular stores, which causes calcium channels to be embedded in the cell membrane (CRAC channels). As long as the T cells are stimulated, the two potassium channels KV1.3 and KCa3.1 maintain the driving force for calcium influx, thus keeping the T cells activated. Our aims were to investigate whether the two potassium channels KV1.3 and KCa3.1 were upregulated in mucosal biopsies from patients with active UC and whether there were correlations between the expression of the channels and the disease severity assessed by endoscopic and histological evaluation. Moreover, we used a rat colitis model (dextran sodium sulphate-induced) to examine the effect of pharmacological inhibition of KV1.3 and KCa3.1 on inflammation. We found that the expression of T cell potassium channel, KV1.3, was increased in active UC and a higher expression correlated well with both the endoscopic and the histological degree of inflammation. This suggests KV1.3 to be involved in the inflammatory process of UC. We did not find an increase of the other potassium channel, KCa3.1, at the gene expression level, but the channels were definitely present in the infiltrating T cells as examined by immunostaining. Preliminary gene expression data showed similar changes of gene expression in biopsies from Crohns disease (CD) patients. In addition, we conducted first pilot studies investigating whether pharmacological blockade of the channels ameliorates colitis in the rat DSS-model. We found a tendency towards less endoscopic inflammation in the acute phase (at day 7 and 10). However, at study termination, the improvement of inflammation failed to reach a significant level, presumably because of insufficient compound absorption from the intestine (based on low plasma concentration and previously reported amelioration of colitis by inhibiting KCa3.1). Based on these findings in our target identification study, it is suggested that both KV1.3 and KCa3.1 play a role in the inflammation of UC and possibly of CD and represent new pharmacological targets.
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Affiliation(s)
- Lars Koch Hansen
- Department of Gastroenterology and Hepatology, Vejle Hospital, Lillebaelt Hospital. Kabbeltoft 25, 7100 Vejle, Denmark.
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Chen R, Chung SH. Binding modes of two scorpion toxins to the voltage-gated potassium channel kv1.3 revealed from molecular dynamics. Toxins (Basel) 2014; 6:2149-61. [PMID: 25054783 PMCID: PMC4113748 DOI: 10.3390/toxins6072149] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/08/2014] [Accepted: 07/10/2014] [Indexed: 12/13/2022] Open
Abstract
Molecular dynamics (MD) simulations are used to examine the binding modes of two scorpion toxins, margatoxin (MgTx) and hongotoxin (HgTx), to the voltage gated K+ channel, Kv1.3. Using steered MD simulations, we insert either Lys28 or Lys35 of the toxins into the selectivity filter of the channel. The MgTx-Kv1.3 complex is stable when the side chain of Lys35 from the toxin occludes the channel filter, suggesting that Lys35 is the pore-blocking residue for Kv1.3. In this complex, Lys28 of the toxin forms one additional salt bridge with Asp449 just outside the filter of the channel. On the other hand, HgTx forms a stable complex with Kv1.3 when the side chain of Lys28 but not Lys35 protrudes into the filter of the channel. A survey of all the possible favorable binding modes of HgTx-Kv1.3 is carried out by rotating the toxin at 3° intervals around the channel axis while the position of HgTx-Lys28 relative to the filter is maintained. We identify two possible favorable binding modes: HgTx-Arg24 can interact with either Asp433 or Glu420 on the vestibular wall of the channel. The dissociation constants calculated from the two binding modes of HgTx-Kv1.3 differ by approximately 20 fold, suggesting that the two modes are of similar energetics.
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Affiliation(s)
- Rong Chen
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
| | - Shin-Ho Chung
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
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Wang J, Qian W, Liu J, Zhao J, Yu P, Jiang L, Zhou J, Gao R, Xiao H. Effect of methamphetamine on the microglial damage: role of potassium channel Kv1.3. PLoS One 2014; 9:e88642. [PMID: 24533129 PMCID: PMC3922974 DOI: 10.1371/journal.pone.0088642] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 01/07/2014] [Indexed: 11/29/2022] Open
Abstract
Methamphetamine (Meth) abusing represents a major public health problem worldwide. Meth has long been known to induce neurotoxicity. However, the mechanism is still remained poorly understood. Growing evidences indicated that the voltage-gated potassium channels (Kv) were participated in neuronal damage and microglia function. With the whole cell patch clamp, we found that Meth significantly increased the outward K+ currents, therefore, we explored whether Kv1.3, one of the major K+ channels expressed in microglia, was involved in Meth-induced microglia damage. Our study showed that Meth significantly increased the cell viability in a dose dependent manner, while the Kv blocker, tetraethylamine (TEA), 4-Aminopyridine (4-AP) and Kv1.3 specific antagonist margatoxin (MgTx), prevented against the damage mediated by Meth. Interestingly, treatment of cells with Meth resulted in increasing expression of Kv1.3 rather than Kv1.5, at both mRNA and protein level, which is partially blocked by MgTx. Furthermore, Meth also stimulated a significant increased expression of IL-6 and TNF-α at protein level, which was significantly inhibited by MgTx. Taken together, these results demonstrated that Kv1.3 was involved in Meth-mediated microglial damage, providing the potential target for the development of therapeutic strategies for Meth abuse.
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Affiliation(s)
- Jun Wang
- Key Lab of Modern Toxicology, Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Wenyi Qian
- Key Lab of Modern Toxicology, Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Jingli Liu
- Key Lab of Modern Toxicology, Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China
- Departments of Experimental Medicine, Nanjing Drum Tower Hospital, Nanjing Medical University, Nanjing, China
| | - Jingjing Zhao
- Key Lab of Modern Toxicology, Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Pan Yu
- Key Lab of Modern Toxicology, Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Lei Jiang
- Department of Emergency Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jing Zhou
- Key Lab of Modern Toxicology, Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Rong Gao
- Key Lab of Modern Toxicology, Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Hang Xiao
- Key Lab of Modern Toxicology, Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China
- * E-mail:
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Rashid MH, Heinzelmann G, Huq R, Tajhya RB, Chang SC, Chhabra S, Pennington MW, Beeton C, Norton RS, Kuyucak S. A potent and selective peptide blocker of the Kv1.3 channel: prediction from free-energy simulations and experimental confirmation. PLoS One 2013; 8:e78712. [PMID: 24244345 PMCID: PMC3820677 DOI: 10.1371/journal.pone.0078712] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 09/23/2013] [Indexed: 12/27/2022] Open
Abstract
The voltage-gated potassium channel Kv1.3 is a well-established target for treatment of autoimmune diseases. ShK peptide from a sea anemone is one of the most potent blockers of Kv1.3 but its application as a therapeutic agent for autoimmune diseases is limited by its lack of selectivity against other Kv channels, in particular Kv1.1. Accurate models of Kv1.x-ShK complexes suggest that specific charge mutations on ShK could considerably enhance its specificity for Kv1.3. Here we evaluate the K18A mutation on ShK, and calculate the change in binding free energy associated with this mutation using the path-independent free energy perturbation and thermodynamic integration methods, with a novel implementation that avoids convergence problems. To check the accuracy of the results, the binding free energy differences were also determined from path-dependent potential of mean force calculations. The two methods yield consistent results for the K18A mutation in ShK and predict a 2 kcal/mol gain in Kv1.3/Kv1.1 selectivity free energy relative to wild-type peptide. Functional assays confirm the predicted selectivity gain for ShK[K18A] and suggest that it will be a valuable lead in the development of therapeutics for autoimmune diseases.
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Affiliation(s)
- M. Harunur Rashid
- School of Physics, University of Sydney, Sydney, New South Wales, Australia
| | | | - 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
| | - 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
| | - Shih Chieh Chang
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Sandeep Chhabra
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | | | - Christine Beeton
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- * E-mail: (RSN); (SK)
| | - Serdar Kuyucak
- School of Physics, University of Sydney, Sydney, New South Wales, Australia
- * E-mail: (RSN); (SK)
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Wu J, Zhong D, Wu X, Sha M, Kang L, Ding Z. Voltage-gated potassium channel Kv1.3 is highly expressed in human osteosarcoma and promotes osteosarcoma growth. Int J Mol Sci 2013; 14:19245-56. [PMID: 24065104 PMCID: PMC3794831 DOI: 10.3390/ijms140919245] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 08/22/2013] [Accepted: 09/10/2013] [Indexed: 01/28/2023] Open
Abstract
Deregulation of voltage-gated potassium channel subunit Kv1.3 has been reported in many tumors. Kv1.3 promotes tumorigenesis by enhancing cell proliferation while suppressing apoptosis. However, the expression and function of Kv1.3 in osteosarcoma are unknown. In the present study, we detected the expression of Kv1.3 in human osteosarcoma cells and tissues by RT-PCR, Western blot and immunohistochemistry. We further examined cell proliferation and apoptosis in osteosarcoma MG-63 cells and xenografts following knockdown of Kv1.3 by short hairpin RNA (shRNA). We found that Kv1.3 was upregulated in human osteosarcoma. Knockdown of Kv1.3 significantly suppressed cell proliferation and increased apoptosis as demonstrated by enhanced cleavage of poly (ADP-ribose) polymerase (PARP) and the activation of Caspase-3/7. Furthermore, adenovirus delivered shRNA targeting Kv1.3 significantly inhibited the growth of MG-63 xenografts. Taken together, our results suggest that Kv1.3 is a novel molecular target for osterosarcoma therapy.
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Affiliation(s)
- Jin Wu
- Department of Orthopaedics, the Affiliated Southeast Hospital of Xiamen University, Zhangzhou 363000, China; E-Mails: (J.W.); (M.S.)
| | - Daixing Zhong
- Department of Thoracic Surgery, the Affiliated Tangdu Hospital of Fourth Military Medical University, Xi’an 710038, China; E-Mail:
| | - Xinyu Wu
- Department of Neurology, the Affiliated Southeast Hospital of Xiamen University, Zhangzhou 363000, China; E-Mail:
| | - Mo Sha
- Department of Orthopaedics, the Affiliated Southeast Hospital of Xiamen University, Zhangzhou 363000, China; E-Mails: (J.W.); (M.S.)
| | - Liangqi Kang
- Department of Orthopaedics, the Affiliated Southeast Hospital of Xiamen University, Zhangzhou 363000, China; E-Mails: (J.W.); (M.S.)
- Authors to whom correspondence should be addressed: E-Mails: (L.K.); (Z.D.); Tel./Fax: +86-596-2931538 (L.K. & Z.D.)
| | - Zhenqi Ding
- Department of Orthopaedics, the Affiliated Southeast Hospital of Xiamen University, Zhangzhou 363000, China; E-Mails: (J.W.); (M.S.)
- Authors to whom correspondence should be addressed: E-Mails: (L.K.); (Z.D.); Tel./Fax: +86-596-2931538 (L.K. & Z.D.)
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Dang B, Kubota T, Mandal K, Bezanilla F, Kent SBH. Native chemical ligation at Asx-Cys, Glx-Cys: chemical synthesis and high-resolution X-ray structure of ShK toxin by racemic protein crystallography. J Am Chem Soc 2013; 135:11911-9. [PMID: 23919482 PMCID: PMC3838204 DOI: 10.1021/ja4046795] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have re-examined the utility of native chemical ligation at -Gln/Glu-Cys- [Glx-Cys] and -Asn/Asp-Cys- [Asx-Cys] sites. Using the improved thioaryl catalyst 4-mercaptophenylacetic acid (MPAA), native chemical ligation could be performed at -Gln-Cys- and Asn-Cys- sites without side reactions. After optimization, ligation at a -Glu-Cys- site could also be used as a ligation site, with minimal levels of byproduct formation. However, -Asp-Cys- is not appropriate for use as a site for native chemical ligation because of formation of significant amounts of β-linked byproduct. The feasibility of native chemical ligation at -Gln-Cys- enabled a convergent total chemical synthesis of the enantiomeric forms of the ShK toxin protein molecule. The D-ShK protein molecule was ~50,000-fold less active in blocking the Kv1.3 channel than the L-ShK protein molecule. Racemic protein crystallography was used to obtain high-resolution X-ray diffraction data for ShK toxin. The structure was solved by direct methods and showed significant differences from the previously reported NMR structures in some regions of the ShK protein molecule.
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Affiliation(s)
- Bobo Dang
- Department of Chemistry, Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics. University of Chicago, Chicago, IL 60637
| | - Tomoya Kubota
- Department of Chemistry, Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics. University of Chicago, Chicago, IL 60637
| | - Kalyaneswar Mandal
- Department of Chemistry, Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics. University of Chicago, Chicago, IL 60637
| | - Francisco Bezanilla
- Department of Chemistry, Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics. University of Chicago, Chicago, IL 60637
| | - Stephen B. H. Kent
- Department of Chemistry, Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics. University of Chicago, Chicago, IL 60637
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Fu XX, Du LL, Zhao N, Dong Q, Liao YH, Du YM. 18β-Glycyrrhetinic acid potently inhibits Kv1.3 potassium channels and T cell activation in human Jurkat T cells. J Ethnopharmacol 2013; 148:647-54. [PMID: 23707333 DOI: 10.1016/j.jep.2013.05.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 05/08/2013] [Accepted: 05/14/2013] [Indexed: 05/21/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Licorice has been extensively used in traditional medicines for treatment of many diseases, including inflammations and immunological disorders. Recent studies have shown that the anti-inflammatory and immunomodulation activities of licorice have been attributed to its active component, glycyrretinic acid (GA). GA consists of two isoforms, 18α- and 18β-. However, its mechanism remains poorly understood. AIM OF THE STUDY We compared the effects of two isoforms on Kv1.3 channels in Jurkat T cells and further characterized the inhibition of Kv1.3 channels by 18β-GA in CHO cells. In addition, we examined the effects of 18β-GA on Kv1.3 gene expression, Ca(2+) influx, proliferation, as well as IL-2 production in Jurkat T cells. MATERIALS AND METHODS Whole-cell patch-clamp technique was applied to record Kv1.3 currents in Jurkat T or CHO cells. Real-time PCR and Western blotting were used to detect gene expression. Fluo-4, CCK-8 kit and ELISA kit were used to measure Ca(2+) influx, proliferation, and IL-2 secretion in Jurkat T cells, respectively. RESULTS Superfusion of 18β-GA (10-100 µM) blocked Kv1.3 currents in Jurkat T cells, while 18α-GA at the same concentration had no effect. The 18β-GA induced inhibition had a voltage- and concentration-dependent manner with an IC50 of 23.9±1.5 µM at +40 mV in CHO cells. Furthermore, 18β-GA significantly inhibited Kv1.3 gene expression. In addition, paralleling Kv1.3 inhibition, 18β-GA also inhibited Ca(2+) influx, proliferation as well as IL-2 production in Jurkat T cells. CONCLUSION 18β-GA blocks Kv1.3 channels, which probably involves its anti-inflammatory and immunomodulation effects.
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Affiliation(s)
- Xiao-Xing Fu
- Ion Channelopathy Research Center, Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China
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Kazama I, Maruyama Y. Differential effects of clarithromycin and azithromycin on delayed rectifier K(+)-channel currents in murine thymocytes. Pharm Biol 2013; 51:760-765. [PMID: 23527897 DOI: 10.3109/13880209.2013.764539] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
CONTEXT Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and the channels play crucial roles in the lymphocyte activation and proliferation. Since macrolide antibiotics, such as clarithromycin and azithromycin, exert immunomodulatory effects, they would affect the Kv1.3-channel currents in lymphocytes. OBJECTIVE This study determined the physiological involvement in the mechanisms of immunomodulation by these antibiotics. MATERIALS AND METHODS Employing the standard patch-clamp whole-cell recording technique in murine thymocytes, we examined the effects of 30 and 100 µM clarithromycin and azithromycin on the Kv1.3-channel currents and the membrane capacitance. RESULTS Clarithromycin significantly suppressed the peak currents (30 µM, 178 ± 5.6 to 111 ± 2.0 pA/pF; 100 µM, 277 ± 4.4 to 89.6 ± 10 pA/pF) and the pulse-end currents (30 µM, 47.5 ± 2.2% to 15.5 ± 3.3%; 100 µM, 48.5 ± 1.4% to 15.8 ± 1.0%) of thymocyte Kv1.3-channels without significant effects on the membrane capacitance. In contrast, azithromycin did not affect the channel currents. However, it significantly decreased the membrane capacitance (30 µM, 4.68 ± 0.14 to 3.74 ± 0.13 pF; 100 µM, 4.47 ± 0.06 to 3.37 ± 0.08 pF), indicating its accumulation in the plasma membrane. DISCUSSION AND CONCLUSION This study demonstrated for the first time that clarithromycin exerts inhibitory effects on thymocyte Kv1.3-channel currents, while azithromycin decreases the membrane capacitance without affecting the channel currents. These differences in the effects of the macrolide antibiotics may reflect differences in the mechanisms of immunomodulation by which they control the production of cytokines.
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Affiliation(s)
- Itsuro Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Miyagi, Japan.
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Liu J, Xu P, Collins C, Liu H, Zhang J, Keblesh JP, Xiong H. HIV-1 Tat protein increases microglial outward K(+) current and resultant neurotoxic activity. PLoS One 2013; 8:e64904. [PMID: 23738010 PMCID: PMC3667810 DOI: 10.1371/journal.pone.0064904] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/19/2013] [Indexed: 11/19/2022] Open
Abstract
Microglia plays a crucial role in the pathogenesis of HIV-1-associated neurocognitive disorders. Increasing evidence indicates the voltage-gated potassium (Kv) channels are involved in the regulation of microglia function, prompting us to hypothesize Kv channels may also be involved in microglia-mediated neurotoxic activity in HIV-1-infected brain. To test this hypothesis, we investigated the involvement of Kv channels in the response of microglia to HIV-1 Tat protein. Treatment of rat microglia with HIV-1 Tat protein (200 ng/ml) resulted in pro-inflammatory microglial activation, as indicated by increases in TNF-α, IL-1β, reactive oxygen species, and nitric oxide, which were accompanied by enhanced outward K(+) current and Kv1.3 channel expression. Suppression of microglial Kv1.3 channel activity, either with Kv1.3 channel blockers Margatoxin, 5-(4-Phenoxybutoxy)psoralen, or broad-spectrum K(+) channel blocker 4-Aminopyridine, or by knockdown of Kv1.3 expression via transfection of microglia with Kv1.3 siRNA, was found to abrogate the neurotoxic activity of microglia resulting from HIV-1 Tat exposure. Furthermore, HIV-1 Tat-induced neuronal apoptosis was attenuated with the application of supernatant collected from K(+) channel blocker-treated microglia. Lastly, the intracellular signaling pathways associated with Kv1.3 were investigated and enhancement of microglial Kv1.3 was found to correspond with an increase in Erk1/2 mitogen-activated protein kinase activation. These data suggest targeting microglial Kv1.3 channels may be a potential new avenue of therapy for inflammation-mediated neurological disorders.
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Affiliation(s)
- Jianuo Liu
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail: (JL); (HX)
| | - Peng Xu
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Cory Collins
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Han Liu
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Jingdong Zhang
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - James P. Keblesh
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Huangui Xiong
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail: (JL); (HX)
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Affiliation(s)
- Liangping Zhang
- Heart Failure Institute, Shanghai East Hospital Affiliated to Tongji University, Shanghai 200120, China
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Hu L, Wang T, Gocke AR, Nath A, Zhang H, Margolick JB, Whartenby KA, Calabresi PA. Blockade of Kv1.3 potassium channels inhibits differentiation and granzyme B secretion of human CD8+ T effector memory lymphocytes. PLoS One 2013; 8:e54267. [PMID: 23382885 PMCID: PMC3559683 DOI: 10.1371/journal.pone.0054267] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 12/10/2012] [Indexed: 01/10/2023] Open
Abstract
Increased expression of the voltage-gated potassium channel Kν1.3 on activated effector memory T cells (T(EM)) is associated with pathology in multiple sclerosis (MS). To date, most studies of Kν1.3 channels in MS have focused on CD4+ T(EM) cells. Much less is known about the functional relevance of Kv1.3 on CD8+ T(EM) cells. Herein, we examined the effects of Kν1.3 blockade on CD8+ T cell proliferation, differentiation into cytotoxic effector cells, and release of granzyme B (GrB), a key effector of CD8+ T cell-mediated cytotoxicity. We confirmed the expression of Kv1.3 channels on activated human CD8+ T lymphocytes by immunofluorescent staining. To test the functional relevance of the Kv1.3 channel in CD8+ T cells, we inhibited this channel via pharmacological blockers or a lentiviral-dominant negative (Kv1.xDN) approach and determined the effects of the blockade on critical pathogenic parameters of CD8+ T cells. We found that blockade of Kv1.3 with both lentivirus and pharmacologic agents effectively inhibited cytotoxic effector memory cells' proliferation, secretion of GrB, and their ability to kill neural progenitor cells. Intriguingly, the KvDN transduced T cells exhibited arrested differentiation from central memory (T(CM)) to effector memory (T(EM)) states. Transduction of cells that had already differentiated into T(EM) with KvDN led to their conversion into T(CM). CD8+ T(EM) have a critical role in MS and other autoimmune diseases. Our present results indicate a critical role for Kv1.3 in the conversion of CD8+ T cells into potential pathogenic effector cells with cytotoxic function.
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Affiliation(s)
- Lina Hu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Tongguang Wang
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anne R. Gocke
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hao Zhang
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Joseph B. Margolick
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Katharine A. Whartenby
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Peter A. Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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Somodi S, Balajthy A, Szilágyi O, Pethő Z, Harangi M, Paragh G, Panyi G, Hajdu P. Analysis of the K+ current in human CD4+ T lymphocytes in hypercholesterolemic state. Cell Immunol 2013; 281:20-6. [PMID: 23416720 DOI: 10.1016/j.cellimm.2013.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 12/22/2012] [Accepted: 01/12/2013] [Indexed: 11/18/2022]
Abstract
Atherosclerosis involves immune mechanisms: T lymphocytes are found in atherosclerotic plaques, suggesting their activation during atherogenesis. The predominant voltage-gated potassium channel of T cells, Kv1.3 is a key regulator of the Ca(2+)-dependent activation pathway. In the present experiments we studied the proliferation capacity and functional changes of Kv1.3 channels in T cells from healthy and hypercholestaeremic patients. By means of CFSE-assay (carboxyfluorescein succinimidyl ester) we showed that spontaneous activation rate of lymphocytes in hypercholesterolemia was elevated and the antiCD3/antiCD28 co-stimulation was less effective as compared to the healthy group. Using whole-cell patch-clamping we obtained that the activation and deactivation kinetics of Kv1.3 channels were faster in hypercholesterolemic state but no change in other parameters of Kv1.3 were found (inactivation kinetics, steady-state activation, expression level). We suppose that incorporation of oxLDL species via its raft-rupturing effect can modify proliferative rate of T cells as well as the gating of Kv1.3 channels.
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Affiliation(s)
- Sándor Somodi
- 1st Department of Internal Medicine, University of Debrecen, Medical and Health Science Center, Debrecen, Hungary
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Feng J, Yu C, Wang M, Li Z, Wu Y, Cao Z, Li W, He X, Han S. Expression and characterization of a novel scorpine-like peptide Ev37, from the scorpion Euscorpiops validus. Protein Expr Purif 2012; 88:127-33. [PMID: 23262394 DOI: 10.1016/j.pep.2012.12.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 12/10/2012] [Accepted: 12/12/2012] [Indexed: 11/17/2022]
Abstract
Scorpion venom contains a group of two-domain peptides that function to block potassium channels or have cytolytic activities. These peptides, whose functions are poorly studied, are named β-KTx or scorpine-like peptides. Ev37, the first identified gene in the Euscorpiidae family, which encoded a novel scorpine-like peptide, was cloned from the venom cDNA library of scorpion Euscorpiops validus. Sequence analysis showed that the mature Ev37 peptide contained 78 amino acid residues, which formed two structural domains: a putative α-helical N-terminus and a C-terminus with the cysteine-stabilized α/β motif. The peptide rEv37 and two truncated peptides representing the individual structural domains (Ev37-N and Ev37-C) were expressed in Escherichia coli and purified for functional study. Unlike classic scorpine-like peptides, rEv37 and truncated peptides showed no cytolytic activity against bacteria or eukaryotic cells. Interestingly, rEv37 selectively inhibited Kv1.3 channel without effectively blocking Kv1.1 and Kv1.2 channels. Neither Ev37-N nor Ev37-C blocked Kv1.3 channel, suggesting that both the N-terminal and C-terminal domain of Ev37 are likely involved in the interaction with Kv1.3 channel. These results not only enrich our knowledge of scorpion toxins from scorpine-like subfamily but also provide a novel template with unique structure for designing new types of selective Kv1.3 blockers.
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Affiliation(s)
- Jing Feng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China
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Nguyen W, Howard BL, Jenkins DP, Wulff H, Thompson PE, Manallack DT. Structure-activity relationship exploration of Kv1.3 blockers based on diphenoxylate. Bioorg Med Chem Lett 2012; 22:7106-9. [PMID: 23084278 PMCID: PMC3664202 DOI: 10.1016/j.bmcl.2012.09.080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/18/2012] [Accepted: 09/21/2012] [Indexed: 01/27/2023]
Abstract
Diphenoxylate, a well-known opioid agonist and anti-diarrhoeal agent, was recently found to block Kv1.3 potassium channels, which have been proposed as potential therapeutic targets for a range of autoimmune diseases. The molecular basis for this Kv1.3 blockade was assessed by the selective removal of functional groups from the structure of diphenoxylate as well as a number of other structural variations. Removal of the nitrile functional group and replacement of the C-4 piperidinyl substituents resulted in several compounds with submicromolar IC(50) values.
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Affiliation(s)
- William Nguyen
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Vic. 3052, Australia
| | - Brittany L. Howard
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Vic. 3052, Australia
| | - David P. Jenkins
- Department of Pharmacology, University of California, 451 East Health Sciences Drive, Davis, CA 95616, USA
| | - Heike Wulff
- Department of Pharmacology, University of California, 451 East Health Sciences Drive, Davis, CA 95616, USA
| | - Philip E. Thompson
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Vic. 3052, Australia
| | - David T. Manallack
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Vic. 3052, Australia
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Gąsiorowska J, Teisseyre A, Uryga A, Michalak K. The influence of 8-prenylnaringenin on the activity of voltage-gated Kv1.3 potassium channels in human Jurkat T cells. Cell Mol Biol Lett 2012; 17:559-70. [PMID: 22933043 PMCID: PMC6275880 DOI: 10.2478/s11658-012-0029-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 08/23/2012] [Indexed: 12/25/2022] Open
Abstract
Using the whole-cell patch-clamp technique, we investigated the influence of 8-prenylnaringenin on the activity of the voltage-gated Kv1.3 potassium channels in the human leukemic T lymphocyte cell line Jurkat. 8-prenylnaringenin is a potent plant-derived phytoestrogen that has been found to inhibit cancer cell proliferation. The results show that it inhibited the Kv1.3 channels in a concentration-dependent manner. Complete inhibition occurred at concentrations higher than 10 μM. The inhibitory effect of 8-prenylnaringenin was reversible. It was accompanied by a significant acceleration of channel inactivation without any pronounced change in the activation rate. Of the naringenin derivatives tested to date, 8-prenylnaringenin is the most potent inhibitor of the Kv1.3 channels. The potency of the inhibition may be due to the presence of a prenyl group in the molecule of this flavonoid. The inhibition of the Kv1.3 channels might be involved in the antiproliferative and pro-apoptotic effects of 8-prenylnaringenin that have been observed in cancer cell lines expressing these channels.
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Affiliation(s)
- Justyna Gąsiorowska
- Department of Biophysics, Wrocław Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland
| | - Andrzej Teisseyre
- Department of Biophysics, Wrocław Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland
| | - Anna Uryga
- Department of Biophysics, Wrocław Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland
| | - Krystyna Michalak
- Department of Biophysics, Wrocław Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland
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Abstract
The 34-residue polypeptide maurotoxin (MTx) isolated from scorpion venoms selectively inhibits the current of the voltage-gated potassium channel Kv1.2 by occluding the ion conduction pathway. Here using molecular dynamics simulation as a docking method, the binding modes of MTx to three closely related channels (Kv1.1, Kv1.2 and Kv1.3) are examined. We show that MTx forms more favorable electrostatic interactions with the outer vestibule of Kv1.2 compared to Kv1.1 and Kv1.3, consistent with the selectivity of MTx for Kv1.2 over Kv1.1 and Kv1.3 observed experimentally. One salt bridge in the bound complex of MTx-Kv1.2 forms and breaks in a simulation period of 20ns, suggesting the dynamic nature of toxin-channel interactions. The toxin selectivity likely arises from the differences in the shape of the channel outer vestibule, giving rise to distinct orientations of MTx on block. Potential of mean force calculations show that MTx blocks Kv1.1, Kv1.2 and Kv1.3 with an IC50 value of 6 µM, 0.6nM and 18 µM, respectively.
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Affiliation(s)
- Rong Chen
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail: (RC); (S-HC)
| | - Shin-Ho Chung
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail: (RC); (S-HC)
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