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Capera J, Jainarayanan A, Navarro-Pérez M, Valvo S, Demetriou P, Depoil D, Estadella I, Kvalvaag A, Felce JH, Felipe A, Dustin ML. Dynamics and spatial organization of Kv1.3 at the immunological synapse of human CD4+ T cells. Biophys J 2024; 123:2271-2281. [PMID: 37596785 PMCID: PMC11331042 DOI: 10.1016/j.bpj.2023.08.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/27/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023] Open
Abstract
Formation of the immunological synapse (IS) is a key event during initiation of an adaptive immune response to a specific antigen. During this process, a T cell and an antigen presenting cell form a stable contact that allows the T cell to integrate both internal and external stimuli in order to decide whether to activate. The threshold for T cell activation depends on the strength and frequency of the calcium (Ca2+) signaling induced by antigen recognition, and it must be tightly regulated to avoid undesired harm to healthy cells. Potassium (K+) channels are recruited to the IS to maintain the negative membrane potential required to sustain Ca2+ entry. However, the precise localization of K+ channels within the IS remains unknown. Here, we visualized the dynamic subsynaptic distribution of Kv1.3, the main voltage-gated potassium channel in human T cells. Upon T cell receptor engagement, Kv1.3 polarized toward the synaptic cleft and diffused throughout the F-actin rich distal compartment of the synaptic interface-an effect enhanced by CD2-CD58 corolla formation. As the synapse matured, Kv1.3 clusters were internalized at the center of the IS and released in extracellular vesicles. We propose a model in which specific distribution of Kv1.3 within the synapse indirectly regulates the channel function and that this process is limited through Kv1.3 internalization and release in extracellular vesicles.
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Affiliation(s)
- Jesusa Capera
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; Molecular Physiology Laboratory, Departament de Bioquímica I Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Ashwin Jainarayanan
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - María Navarro-Pérez
- Molecular Physiology Laboratory, Departament de Bioquímica I Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Salvatore Valvo
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Philippos Demetriou
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; The Center for the Study of Haematological and Other Malignancies, Nicosia, Cyprus
| | - David Depoil
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Irene Estadella
- Molecular Physiology Laboratory, Departament de Bioquímica I Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Audun Kvalvaag
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - James H Felce
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica I Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain.
| | - Michael L Dustin
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom.
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Navarro-Pérez M, Capera J, Benavente-Garcia A, Cassinelli S, Colomer-Molera M, Felipe A. Kv1.3 in the spotlight for treating immune diseases. Expert Opin Ther Targets 2024; 28:67-82. [PMID: 38316438 DOI: 10.1080/14728222.2024.2315021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 02/02/2024] [Indexed: 02/07/2024]
Abstract
INTRODUCTION Kv1.3 is the main voltage-gated potassium channel of leukocytes from both the innate and adaptive immune systems. Channel function is required for common processes such as Ca2+ signaling but also for cell-specific events. In this context, alterations in Kv1.3 are associated with multiple immune disorders. Excessive channel activity correlates with numerous autoimmune diseases, while reduced currents result in increased cancer prevalence and immunodeficiencies. AREAS COVERED This review offers a general view of the role of Kv1.3 in every type of leukocyte. Moreover, diseases stemming from dysregulations of the channel are detailed, as well as current advances in their therapeutic research. EXPERT OPINION Kv1.3 arises as a potential immune target in a variety of diseases. Several lines of research focused on channel modulation have yielded positive results. However, among the great variety of specific channel blockers, only one has reached clinical trials. Future investigations should focus on developing simpler administration routes for channel inhibitors to facilitate their entrance into clinical trials. Prospective Kv1.3-based treatments will ensure powerful therapies while minimizing undesired side effects.
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Affiliation(s)
- María Navarro-Pérez
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Jesusa Capera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Anna Benavente-Garcia
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Silvia Cassinelli
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Magalí Colomer-Molera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
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Sonkodi B, Marsovszky L, Csorba A, Balog A, Kopper B, Nagy ZZ, Resch MD. Neural Regeneration in Dry Eye Secondary to Systemic Lupus Erythematosus Is Also Disrupted like in Rheumatoid Arthritis, but in a Progressive Fashion. Int J Mol Sci 2023; 24:10680. [PMID: 37445856 DOI: 10.3390/ijms241310680] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/16/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023] Open
Abstract
Our objective in this study was to analyze the aberrant neural regeneration activity in the cornea by means of in vivo confocal microscopy in systemic lupus erythematosus patients with concurrent dry eye disease. We examined 29 systemic lupus erythematosus patients and 29 age-matched healthy control subjects. Corneal nerve fiber density (CNFD, the number of fibers/mm2) and peripheral Langerhans cell morphology were lower (p < 0.05) in systemic lupus erythematosus patients compared to the control group. Interestingly, corneal nerve branch density, corneal nerve fiber length, corneal nerve fiber total branch density, and corneal nerve fiber area showed a negative correlation with disease duration. A negative correlation was also demonstrated between average corneal nerve fiber density and central Langerhans cell density. This is in line with our hypothesis that corneal somatosensory terminal Piezo2 channelopathy-induced impaired Piezo2-Piezo1 crosstalk not only disrupts regeneration and keeps transcription activated, but could lead to Piezo1 downregulation and cell activation on Langerhans cells when we consider a chronic path. Hence, Piezo2 containing mechanosensory corneal nerves and dendritic Langerhans cells could also be regarded as central players in shaping the ocular surface neuroimmune homeostasis through the Piezo system. Moreover, lost autoimmune neuroinflammation compensation, lost phagocytic self-eating capacity, and lost transcription regulation, not to mention autoantibodies against vascular heparin sulfate proteoglycans and phospholipids, could all contribute to the progressive fashion of dry eye disease in systemic lupus erythematosus.
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Affiliation(s)
- Balázs Sonkodi
- Department of Health Sciences and Sport Medicine, Hungarian University of Sports Science, 1123 Budapest, Hungary
| | - László Marsovszky
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
| | - Anita Csorba
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
| | - Attila Balog
- Department of Rheumatology and Immunology, Faculty of Medicine, Albert Szent-Györgyi Health Center, University of Szeged, 6725 Szeged, Hungary
| | - Bence Kopper
- Faculty of Kinesiology, Hungarian University of Sports Science, 1123 Budapest, Hungary
| | - Zoltán Zsolt Nagy
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
| | - Miklós D Resch
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
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Davis LC, Morgan AJ, Galione A. Acidic Ca 2+ stores and immune-cell function. Cell Calcium 2021; 101:102516. [PMID: 34922066 DOI: 10.1016/j.ceca.2021.102516] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/03/2021] [Accepted: 12/04/2021] [Indexed: 12/11/2022]
Abstract
Acidic organelles act as intracellular Ca2+ stores; they actively sequester Ca2+ in their lumina and release it to the cytosol upon activation of endo-lysosomal Ca2+ channels. Recent data suggest important roles of endo-lysosomal Ca2+ channels, the Two-Pore Channels (TPCs) and the TRPML channels (mucolipins), in different aspects of immune-cell function, particularly impacting membrane trafficking, vesicle fusion/fission and secretion. Remarkably, different channels on the same acidic vesicles can couple to different downstream physiology. Endo-lysosomal Ca2+ stores can act under different modalities, be they acting alone (via local Ca2+ nanodomains around TPCs/TRPMLs) or in conjunction with the ER Ca2+ store (to either promote or suppress global ER Ca2+ release). These different modalities impinge upon functions as broad as phagocytosis, cell-killing, anaphylaxis, immune memory, thrombostasis, and chemotaxis.
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Affiliation(s)
- Lianne C Davis
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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Voros O, Panyi G, Hajdu P. Immune Synapse Residency of Orai1 Alters Ca 2+ Response of T Cells. Int J Mol Sci 2021; 22:ijms222111514. [PMID: 34768945 PMCID: PMC8583858 DOI: 10.3390/ijms222111514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/11/2021] [Accepted: 10/18/2021] [Indexed: 12/19/2022] Open
Abstract
CRAC, which plays important role in Ca2+-dependent T-lymphocyte activation, is composed of the ER-resident STIM1 and the plasma membrane Orai1 pore-forming subunit. Both accumulate at the immunological synapse (IS) between a T cell and an antigen-presenting cell (APC). We hypothesized that adapter/interacting proteins regulate Orai1 residence in the IS. We could show that mGFP-tagged Orai1-Full channels expressed in Jurkat cells had a biphasic IS-accumulation kinetics peaked at 15 min. To understand the background of Orai1 IS-redistribution we knocked down STIM1 and SAP97 (adaptor protein with a short IS-residency (15 min) and ability to bind Orai1 N-terminus): the mGFP-Orai1-Full channels kept on accumulating in the IS up to the 60th minute in the STIM1- and SAP97-lacking Jurkat cells. Deletion of Orai1 N terminus (mGFP-Orai1-Δ72) resulted in the same time course as described for STIM1/SAP97 knock-down cells. Ca2+-imaging of IS-engaged T-cells revealed that of Orai1 residency modifies the Ca2+-response: cells expressing mGFP-Orai1-Δ72 construct or mGFP-Orai1-Full in SAP-97 knock-down cells showed higher number of Ca2+-oscillation up to the 90th minute after IS formation. Overall, these data suggest that SAP97 may contribute to the short-lived IS-residency of Orai1 and binding of STIM1 to Orai1 N-terminus is necessary for SAP97-Orai1 interaction.
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Affiliation(s)
- Orsolya Voros
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (O.V.); (G.P.)
| | - György Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (O.V.); (G.P.)
| | - Péter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Dentistry, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary
- Correspondence: ; Tel.: +36-52-258603
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6
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Vallejo-Gracia A, Sastre D, Colomer-Molera M, Solé L, Navarro-Pérez M, Capera J, Roig SR, Pedrós-Gámez O, Estadella I, Szilágyi O, Panyi G, Hajdú P, Felipe A. KCNE4-dependent functional consequences of Kv1.3-related leukocyte physiology. Sci Rep 2021; 11:14632. [PMID: 34272451 PMCID: PMC8285421 DOI: 10.1038/s41598-021-94015-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
The voltage-dependent potassium channel Kv1.3 plays essential roles in the immune system, participating in leukocyte activation, proliferation and apoptosis. The regulatory subunit KCNE4 acts as an ancillary peptide of Kv1.3, modulates K+ currents and controls channel abundance at the cell surface. KCNE4-dependent regulation of the oligomeric complex fine-tunes the physiological role of Kv1.3. Thus, KCNE4 is crucial for Ca2+-dependent Kv1.3-related leukocyte functions. To better understand the role of KCNE4 in the regulation of the immune system, we manipulated its expression in various leukocyte cell lines. Jurkat T lymphocytes exhibit low KCNE4 levels, whereas CY15 dendritic cells, a model of professional antigen-presenting cells, robustly express KCNE4. When the cellular KCNE4 abundance was increased in T cells, the interaction between KCNE4 and Kv1.3 affected important T cell physiological features, such as channel rearrangement in the immunological synapse, cell growth, apoptosis and activation, as indicated by decreased IL-2 production. Conversely, ablation of KCNE4 in dendritic cells augmented proliferation. Furthermore, the LPS-dependent activation of CY15 cells, which induced Kv1.3 but not KCNE4, increased the Kv1.3-KCNE4 ratio and increased the expression of free Kv1.3 without KCNE4 interaction. Our results demonstrate that KCNE4 is a pivotal regulator of the Kv1.3 channelosome, which fine-tunes immune system physiology by modulating Kv1.3-associated leukocyte functions.
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Affiliation(s)
- Albert Vallejo-Gracia
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain.,Virology and Immunology, Gladstone Institutes, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Daniel Sastre
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
| | - Magalí Colomer-Molera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
| | - Laura Solé
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain.,Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - María Navarro-Pérez
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
| | - Jesusa Capera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
| | - Sara R Roig
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
| | - Oriol Pedrós-Gámez
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
| | - Irene Estadella
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
| | - Orsolya Szilágyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 400, 1 Egyetem Sq., Debrecen, 4032, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 400, 1 Egyetem Sq., Debrecen, 4032, Hungary
| | - Péter Hajdú
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 400, 1 Egyetem Sq., Debrecen, 4032, Hungary
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain.
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Shi S, Zhao Q, Ke C, Long S, Zhang F, Zhang X, Li Y, Liu X, Hu H, Yin S. Loureirin B Exerts its Immunosuppressive Effects by Inhibiting STIM1/Orai1 and K V1.3 Channels. Front Pharmacol 2021; 12:685092. [PMID: 34248635 PMCID: PMC8268022 DOI: 10.3389/fphar.2021.685092] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/11/2021] [Indexed: 11/16/2022] Open
Abstract
Loureirin B (LrB) is a constituent extracted from traditional Chinese medicine Resina Draconis. It has broad biological functions and an impressive immunosuppressive effect that has been supported by numerous studies. However, the molecular mechanisms underlying Loureirin B-induced immune suppression are not fully understood. We previously reported that Loureirin B inhibited KV1.3 channel, calcium ion (Ca2+) influx, and interleukin-2 (IL-2) secretion in Jurkat T cells. In this study, we applied CRISPR/Cas9 to edit KV1.3 coding gene KCNA3 and successfully generated a KV1.3 knockout (KO) cell model to determine whether KV1.3 KO was sufficient to block the Loureirin B-induced immunosuppressive effect. Surprisingly, we showed that Loureirin B could still inhibit Ca2+ influx and IL-2 secretion in the Jurkat T cells in the absence of KV1.3 although KO KV1.3 reduced about 50% of Ca2+ influx and 90% IL-2 secretion compared with that in the wild type cells. Further experiments showed that Loureirin B directly inhibited STIM1/Orai1 channel in a dose-dependent manner. Our results suggest that Loureirin B inhibits Ca2+ influx and IL-2 secretion in Jurkat T cells by inhibiting both KV1.3 and STIM1/Orai1 channels. These studies also revealed an additional molecular target for Loureirin B-induced immunosuppressive effect, which makes it a promising leading compound for treating autoimmune diseases.
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Affiliation(s)
- Shujuan Shi
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Qianru Zhao
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Caihua Ke
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Siru Long
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Feng Zhang
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Xu Zhang
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Yi Li
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Xinqiao Liu
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Hongzhen Hu
- Department of Anesthesiology, the Center for the Study of Itch & Sensory Disorders, Washington University School of Medicine, St. Louis, MO, United States
| | - Shijin Yin
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
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8
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Khodoun M, Chimote AA, Ilyas FZ, Duncan HJ, Moncrieffe H, Kant KS, Conforti L. Targeted knockdown of Kv1.3 channels in T lymphocytes corrects the disease manifestations associated with systemic lupus erythematosus. SCIENCE ADVANCES 2020; 6:6/47/eabd1471. [PMID: 33208373 PMCID: PMC7673800 DOI: 10.1126/sciadv.abd1471] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 10/02/2020] [Indexed: 05/16/2023]
Abstract
Lupus nephritis (LN) is an autoimmune disease with substantial morbidity/mortality and limited efficacy of available therapies. Memory T (Tm) lymphocytes infiltrate LN kidneys, contributing to organ damage. Analysis of LN, diabetic nephropathy, and healthy donor kidney biopsies revealed high infiltration of active CD8+ Tm cells expressing high voltage-dependent Kv1.3 potassium channels-key T cell function regulators-in LN. Nanoparticles that selectively down-regulate Kv1.3 in Tm cells (Kv1.3-NPs) reduced CD40L and interferon-γ (IFNγ) in Tm cells from LN patients in vitro. Kv1.3-NPs were tested in humanized LN mice obtained by engrafting peripheral blood mononuclear cells (PBMCs) from LN patients into immune-deficient mice. LN mice exhibited features of the disease: increased IFNγ and CD3+CD8+ T cell renal infiltration, and reduced survival versus healthy donor PBMC engrafted mice. Kv1.3-NP treatment of patient PBMCs before engraftment decreased CD40L/IFNγ and prolonged survival of LN mice. These data show the potential benefits of targeting Kv1.3 in LN.
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Affiliation(s)
- Marat Khodoun
- Division of Rheumatology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Ameet A Chimote
- Division of Nephrology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Farhan Z Ilyas
- Division of Nephrology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Heather J Duncan
- Division of Nephrology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Halima Moncrieffe
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
| | - K Shashi Kant
- Division of Nephrology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Laura Conforti
- Division of Nephrology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA.
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9
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Comparative transcriptome analysis reveals a potential role for CaMK4 in γδT17 cells from systemic lupus erythematosus patients with lupus nephritis. Int Immunopharmacol 2020; 80:106139. [DOI: 10.1016/j.intimp.2019.106139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/15/2019] [Accepted: 12/18/2019] [Indexed: 01/30/2023]
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10
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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] [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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11
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Wang X, Li G, Guo J, Zhang Z, Zhang S, Zhu Y, Cheng J, Yu L, Ji Y, Tao J. Kv1.3 Channel as a Key Therapeutic Target for Neuroinflammatory Diseases: State of the Art and Beyond. Front Neurosci 2020; 13:1393. [PMID: 31992966 PMCID: PMC6971160 DOI: 10.3389/fnins.2019.01393] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 12/10/2019] [Indexed: 12/26/2022] Open
Abstract
It remains a challenge for the effective treatment of neuroinflammatory disease, including multiple sclerosis (MS), stroke, epilepsy, and Alzheimer’s and Parkinson’s disease. The voltage-gated potassium Kv1.3 channel is of interest, which is considered as a novel therapeutic target for treating neuroinflammatory disorders due to its crucial role in subsets of T lymphocytes as well as microglial cells. Toxic animals, such as sea anemones, scorpions, spiders, snakes, and cone snails, can produce a variety of toxins that act on the Kv1.3 channel. The Stichodactyla helianthus K+ channel blocking toxin (ShK) from the sea anemone S. helianthus is proved as a classical blocker of Kv1.3. One of the synthetic analogs ShK-186, being developed as a therapeutic for autoimmune diseases, has successfully completed first-in-man Phase 1 trials. In addition to addressing the recent progress on the studies underlying the pharmacological characterizations of ShK on MS, the review will also explore the possibility for clinical treatment of ShK-like Kv1.3 blocking polypeptides on other neuroinflammatory diseases.
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Affiliation(s)
- Xiaoli Wang
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Guoyi Li
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jingkang Guo
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Zhiping Zhang
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Shuzhang Zhang
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Yudan Zhu
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jiwei Cheng
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lu Yu
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yonghua Ji
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China,Xinhua Translational Institute for Cancer Pain, Shanghai, China
| | - Jie Tao
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Putuo Clinical Medical School, Anhui Medical University, Shanghai, China
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12
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Pérez-Verdaguer M, Capera J, Ortego-Domínguez M, Bielanska J, Comes N, Montoro RJ, Camps M, Felipe A. Caveolar targeting links Kv1.3 with the insulin-dependent adipocyte physiology. Cell Mol Life Sci 2018; 75:4059-4075. [PMID: 29947924 PMCID: PMC11105548 DOI: 10.1007/s00018-018-2851-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 05/14/2018] [Accepted: 06/05/2018] [Indexed: 12/23/2022]
Abstract
The voltage-dependent potassium channel Kv1.3 participates in peripheral insulin sensitivity. Genetic ablation of Kv1.3 triggers resistance to diet-induced weight gain, thereby pointing to this protein as a pharmacological target for obesity and associated type II diabetes. However, this role is under intense debate because Kv1.3 expression in adipose tissue raises controversy. We demonstrated that Kv1.3 is expressed in white adipose tissue from humans and rodents. Moreover, other channels, such as Kv1.1, Kv1.2, Kv1.4 and especially Kv1.5, from the same Shaker family are also present. Although elevated insulin levels and adipogenesis remodel the Kv phenotype, which could lead to multiple heteromeric complexes, Kv1.3 markedly participates in the insulin-dependent regulation of glucose uptake in mature adipocytes. Adipocyte differentiation increased the expression of Kv1.3, which is targeted to caveolae by molecular interactions with caveolin 1. Using a caveolin 1-deficient 3T3-L1 adipocyte cell line, we demonstrated that the localization of Kv1.3 in caveolar raft structures is important for proper insulin signaling. Insulin-dependent phosphorylation of the channel occurs at the onset of insulin-mediated signaling. However, when Kv1.3 was spatially outside of these lipid microdomains, impaired phosphorylation was exhibited. Our data shed light on the putative role of Kv1.3 in weight gain and insulin-dependent responses contributing to knowledge about adipocyte physiology.
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Affiliation(s)
- Mireia Pérez-Verdaguer
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Jesusa Capera
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - María Ortego-Domínguez
- Dpto. de Fisiología Médica y Biofísica, Universidad de Sevilla, Av. Dr. Fedriani, s/n., 41009, Seville, Spain
| | - Joanna Bielanska
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Max-Planck-Institute of Experimental Medicine, Molecular Biology of Neuronal Signals, AG Oncophysiology, Hermann-Rein-Str. 3, 37075, Göttingen, Germany
| | - Núria Comes
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Rafael J Montoro
- Dpto. de Fisiología Médica y Biofísica, Universidad de Sevilla, Av. Dr. Fedriani, s/n., 41009, Seville, Spain
| | - Marta Camps
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Antonio Felipe
- Molecular Physiology Laboratory, Dpt. de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
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13
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A complex of Neuroplastin and Plasma Membrane Ca 2+ ATPase controls T cell activation. Sci Rep 2017; 7:8358. [PMID: 28827723 PMCID: PMC5566957 DOI: 10.1038/s41598-017-08519-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 07/10/2017] [Indexed: 12/24/2022] Open
Abstract
The outcome of T cell activation is determined by mechanisms that balance Ca2+ influx and clearance. Here we report that murine CD4 T cells lacking Neuroplastin (Nptn -/-), an immunoglobulin superfamily protein, display elevated cytosolic Ca2+ and impaired post-stimulation Ca2+ clearance, along with increased nuclear levels of NFAT transcription factor and enhanced T cell receptor-induced cytokine production. On the molecular level, we identified plasma membrane Ca2+ ATPases (PMCAs) as the main interaction partners of Neuroplastin. PMCA levels were reduced by over 70% in Nptn -/- T cells, suggesting an explanation for altered Ca2+ handling. Supporting this, Ca2+ extrusion was impaired while Ca2+ levels in internal stores were increased. T cells heterozygous for PMCA1 mimicked the phenotype of Nptn -/- T cells. Consistent with sustained Ca2+ levels, differentiation of Nptn -/- T helper cells was biased towards the Th1 versus Th2 subset. Our study thus establishes Neuroplastin-PMCA modules as important regulators of T cell activation.
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14
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Shen B, Cao Z, Li W, Sabatier JM, Wu Y. Treating autoimmune disorders with venom-derived peptides. Expert Opin Biol Ther 2017; 17:1065-1075. [DOI: 10.1080/14712598.2017.1346606] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Bingzheng Shen
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, China
- Department of Pharmacy, Renmin Hospital, Wuhan University, Wuhan, China
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, China
| | | | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, China
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15
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Li T, Lu G, Chiang EY, Chernov-Rogan T, Grogan JL, Chen J. High-throughput electrophysiological assays for voltage gated ion channels using SyncroPatch 768PE. PLoS One 2017; 12:e0180154. [PMID: 28683073 PMCID: PMC5500279 DOI: 10.1371/journal.pone.0180154] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/09/2017] [Indexed: 01/08/2023] Open
Abstract
Ion channels regulate a variety of physiological processes and represent an important class of drug target. Among the many methods of studying ion channel function, patch clamp electrophysiology is considered the gold standard by providing the ultimate precision and flexibility. However, its utility in ion channel drug discovery is impeded by low throughput. Additionally, characterization of endogenous ion channels in primary cells remains technical challenging. In recent years, many automated patch clamp (APC) platforms have been developed to overcome these challenges, albeit with varying throughput, data quality and success rate. In this study, we utilized SyncroPatch 768PE, one of the latest generation APC platforms which conducts parallel recording from two-384 modules with giga-seal data quality, to push these 2 boundaries. By optimizing various cell patching parameters and a two-step voltage protocol, we developed a high throughput APC assay for the voltage-gated sodium channel Nav1.7. By testing a group of Nav1.7 reference compounds’ IC50, this assay was proved to be highly consistent with manual patch clamp (R > 0.9). In a pilot screening of 10,000 compounds, the success rate, defined by > 500 MΩ seal resistance and >500 pA peak current, was 79%. The assay was robust with daily throughput ~ 6,000 data points and Z’ factor 0.72. Using the same platform, we also successfully recorded endogenous voltage-gated potassium channel Kv1.3 in primary T cells. Together, our data suggest that SyncroPatch 768PE provides a powerful platform for ion channel research and drug discovery.
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Affiliation(s)
- Tianbo Li
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., South San Francisco, California, United States of America
- * E-mail: (TL); (JC)
| | - Gang Lu
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., South San Francisco, California, United States of America
| | - Eugene Y. Chiang
- Department of Cancer Immunology, Genentech Inc., South San Francisco, California, United States of America
| | - Tania Chernov-Rogan
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., South San Francisco, California, United States of America
| | - Jane L. Grogan
- Department of Cancer Immunology, Genentech Inc., South San Francisco, California, United States of America
| | - Jun Chen
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., South San Francisco, California, United States of America
- * E-mail: (TL); (JC)
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16
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Venom-derived peptide inhibitors of voltage-gated potassium channels. Neuropharmacology 2017; 127:124-138. [PMID: 28689025 DOI: 10.1016/j.neuropharm.2017.07.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/02/2017] [Accepted: 07/04/2017] [Indexed: 12/11/2022]
Abstract
Voltage-gated potassium channels play a key role in human physiology and pathology. Reflecting their importance, numerous channelopathies have been characterised that arise from mutations in these channels or from autoimmune attack on the channels. Voltage-gated potassium channels are also the target of a broad range of peptide toxins from venomous organisms, including sea anemones, scorpions, spiders, snakes and cone snails; many of these peptides bind to the channels with high potency and selectivity. In this review we describe the various classes of peptide toxins that block these channels and illustrate the broad range of three-dimensional structures that support channel blockade. The therapeutic opportunities afforded by these peptides are also highlighted. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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17
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Martínez-Mármol R, Styrczewska K, Pérez-Verdaguer M, Vallejo-Gracia A, Comes N, Sorkin A, Felipe A. Ubiquitination mediates Kv1.3 endocytosis as a mechanism for protein kinase C-dependent modulation. Sci Rep 2017; 7:42395. [PMID: 28186199 PMCID: PMC5301257 DOI: 10.1038/srep42395] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 01/09/2017] [Indexed: 12/29/2022] Open
Abstract
The voltage-dependent potassium channel Kv1.3 plays essential physiological functions in the immune system. Kv1.3, regulating the membrane potential, facilitates downstream Ca2+ -dependent pathways and becomes concentrated in specific membrane microdomains that serve as signaling platforms. Increased and/or delocalized expression of the channel is observed at the onset of several autoimmune diseases. In this work, we show that adenosine (ADO), which is a potent endogenous modulator, stimulates PKC, thereby causing immunosuppression. PKC activation triggers down-regulation of Kv1.3 by inducing a clathrin-mediated endocytic event that targets the channel to lysosomal-degradative compartments. Therefore, the abundance of Kv1.3 at the cell surface decreases, which is clearly compatible with an effective anti-inflammatory response. This mechanism requires ubiquitination of Kv1.3, catalyzed by the E3 ubiquitin-ligase Nedd4-2. Postsynaptic density protein 95 (PSD-95), a member of the MAGUK family, recruits Kv1.3 into lipid-raft microdomains and protects the channel against ubiquitination and endocytosis. Therefore, the Kv1.3/PSD-95 association fine-tunes the anti-inflammatory response in leukocytes. Because Kv1.3 is a promising multi-therapeutic target against human pathologies, our results have physiological relevance. In addition, this work elucidates the ADO-dependent PKC-mediated molecular mechanism that triggers immunomodulation by targeting Kv1.3 in leukocytes.
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Affiliation(s)
- Ramón Martínez-Mármol
- Molecular Physiology laboratory, Departament de Bioquímica i Biomedicna Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain.,Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Katarzyna Styrczewska
- Molecular Physiology laboratory, Departament de Bioquímica i Biomedicna Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Mireia Pérez-Verdaguer
- Molecular Physiology laboratory, Departament de Bioquímica i Biomedicna Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Albert Vallejo-Gracia
- Molecular Physiology laboratory, Departament de Bioquímica i Biomedicna Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Núria Comes
- Molecular Physiology laboratory, Departament de Bioquímica i Biomedicna Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain.,Laboratory of Neurophysiology, Universitat de Barcelona and Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Alexander Sorkin
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Antonio Felipe
- Molecular Physiology laboratory, Departament de Bioquímica i Biomedicna Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain
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18
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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: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [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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19
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Solé L, Roig SR, Vallejo-Gracia A, Serrano-Albarrás A, Martínez-Mármol R, Tamkun MM, Felipe A. The C-terminal domain of Kv1.3 regulates functional interactions with the KCNE4 subunit. J Cell Sci 2016; 129:4265-4277. [PMID: 27802162 DOI: 10.1242/jcs.191650] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/29/2016] [Indexed: 12/23/2022] Open
Abstract
The voltage-dependent K+ channel Kv1.3 (also known as KCNA3), which plays crucial roles in leukocytes, physically interacts with KCNE4. This interaction inhibits the K+ currents because the channel is retained within intracellular compartments. Thus, KCNE subunits are regulators of K+ channels in the immune system. Although the canonical interactions of KCNE subunits with Kv7 channels are under intensive investigation, the molecular determinants governing the important Kv1.3- KCNE4 association in the immune system are unknown. Our results suggest that the tertiary structure of the C-terminal domain of Kv1.3 is necessary and sufficient for such an interaction. However, this element is apparently not involved in modulating Kv1.3 gating. Furthermore, the KCNE4-dependent intracellular retention of the channel, which negatively affects the activity of Kv1.3, is mediated by two independent and additive mechanisms. First, KCNE4 masks the YMVIEE signature at the C-terminus of Kv1.3, which is crucial for the surface targeting of the channel. Second, we identify a potent endoplasmic reticulum retention motif in KCNE4 that further limits cell surface expression. Our results define specific molecular determinants that play crucial roles in the physiological function of Kv1.3 in leukocytes.
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Affiliation(s)
- Laura Solé
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, Barcelona 08028, Spain.,Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Sara R Roig
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, Barcelona 08028, Spain
| | - Albert Vallejo-Gracia
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, Barcelona 08028, Spain
| | - Antonio Serrano-Albarrás
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, Barcelona 08028, Spain
| | - Ramón Martínez-Mármol
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, Barcelona 08028, Spain.,Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - 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, Avda. Diagonal 643, Barcelona 08028, Spain
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20
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Rational design of a Kv1.3 channel-blocking antibody as a selective immunosuppressant. Proc Natl Acad Sci U S A 2016; 113:11501-11506. [PMID: 27663736 DOI: 10.1073/pnas.1612803113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A variable region fusion strategy was used to generate an immunosuppressive antibody based on a novel "stalk-knob" structural motif in the ultralong complementary-determining region (CDR) of a bovine antibody. The potent Kv1.3 channel inhibitory peptides Moka1-toxin and Vm24-toxin were grafted into different CDRs of the humanized antibodies BVK and Synagis (Syn) using both β-sheet and coiled-coil linkers. Structure-activity relationship efforts led to generation of the fusion protein Syn-Vm24-CDR3L, which demonstrated excellent selectivity and potency against effector human memory T cells (subnanomolar to picomolar EC50 values). This fusion antibody also had significantly improved plasma half-life and serum stability in rodents compared with the parent Vm24 peptide. Finally, this fusion protein showed potent in vivo efficacy in the delayed type hypersensitivity in rats. These results illustrate the utility of antibody CDR fusions as a general and effective strategy to generate long-acting functional antibodies, and may lead to a selective immunosuppressive antibody for the treatment of autoimmune diseases.
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21
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Chimote AA, Hajdu P, Kottyan LC, Harley JB, Yun Y, Conforti L. Nanovesicle-targeted Kv1.3 knockdown in memory T cells suppresses CD40L expression and memory phenotype. J Autoimmun 2016; 69:86-93. [PMID: 26994905 DOI: 10.1016/j.jaut.2016.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 02/06/2023]
Abstract
Ca(2+) signaling controls activation and effector functions of T lymphocytes. Ca(2+) levels also regulate NFAT activation and CD40 ligand (CD40L) expression in T cells. CD40L in activated memory T cells binds to its cognate receptor, CD40, on other cell types resulting in the production of antibodies and pro-inflammatory mediators. The CD40L/CD40 interaction is implicated in the pathogenesis of autoimmune disorders and CD40L is widely recognized as a therapeutic target. Ca(2+) signaling in T cells is regulated by Kv1.3 channels. We have developed lipid nanoparticles that deliver Kv1.3 siRNAs (Kv1.3-NPs) selectively to CD45RO(+) memory T cells and reduce the activation-induced Ca(2+) influx. Herein we report that Kv1.3-NPs reduced NFAT activation and CD40L expression exclusively in CD45RO(+) T cells. Furthermore, Kv1.3-NPs suppressed cytokine release and induced a phenotype switch of T cells from predominantly memory to naïve. These findings indicate that Kv1.3-NPs operate as targeted immune suppressive agents with promising therapeutic potentials.
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Affiliation(s)
- Ameet A Chimote
- Department of Internal Medicine, Division of Nephrology, University of Cincinnati, Cincinnati, OH, USA
| | - Peter Hajdu
- Department of Internal Medicine, Division of Nephrology, University of Cincinnati, Cincinnati, OH, USA
| | - Leah C Kottyan
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - John B Harley
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA; US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA
| | - Yeoheung Yun
- North Carolina A & T State University, Chemical, Biological and Bioengineering Department, Greensboro, NC, USA
| | - Laura Conforti
- Department of Internal Medicine, Division of Nephrology, University of Cincinnati, Cincinnati, OH, USA.
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22
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Caveolin interaction governs Kv1.3 lipid raft targeting. Sci Rep 2016; 6:22453. [PMID: 26931497 PMCID: PMC4773814 DOI: 10.1038/srep22453] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/15/2016] [Indexed: 12/22/2022] Open
Abstract
The spatial localization of ion channels at the cell surface is crucial for their functional role. Many channels localize in lipid raft microdomains, which are enriched in cholesterol and sphingolipids. Caveolae, specific lipid rafts which concentrate caveolins, harbor signaling molecules and their targets becoming signaling platforms crucial in cell physiology. However, the molecular mechanisms involved in such spatial localization are under debate. Kv1.3 localizes in lipid rafts and participates in the immunological response. We sought to elucidate the mechanisms of Kv1.3 surface targeting, which govern leukocyte physiology. Kv1 channels share a putative caveolin-binding domain located at the intracellular N-terminal of the channel. This motif, lying close to the S1 transmembrane segment, is situated near the T1 tetramerization domain and the determinants involved in the Kvβ subunit association. The highly hydrophobic domain (FQRQVWLLF) interacts with caveolin 1 targeting Kv1.3 to caveolar rafts. However, subtle variations of this cluster, putative ancillary associations and different structural conformations can impair the caveolin recognition, thereby altering channel’s spatial localization. Our results identify a caveolin-binding domain in Kv1 channels and highlight the mechanisms that govern the regulation of channel surface localization during cellular processes.
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23
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Grishkan IV, Tosi DM, Bowman MD, Harary M, Calabresi PA, Gocke AR. Antigenic Stimulation of Kv1.3-Deficient Th Cells Gives Rise to a Population of Foxp3-Independent T Cells with Suppressive Properties. THE JOURNAL OF IMMUNOLOGY 2015; 195:1399-1407. [PMID: 26150529 DOI: 10.4049/jimmunol.1403024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 06/12/2015] [Indexed: 12/26/2022]
Abstract
Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the CNS that has been linked with defects in regulatory T cell function. Therefore, strategies to selectively target pathogenic cells via enhanced regulatory T cell activity may provide therapeutic benefit. Kv1.3 is a voltage-gated potassium channel expressed on myelin-reactive T cells from MS patients. Kv1.3-knockout (KO) mice are protected from experimental autoimmune encephalomyelitis, an animal model of MS, and Kv1.3-KO Th cells display suppressive capacity associated with increased IL-10. In this article, we demonstrate that myelin oligodendrocyte glycoprotein-specific Kv1.3-KO Th cells exhibit a unique regulatory phenotype characterized by high CD25, CTLA4, pSTAT5, FoxO1, and GATA1 expression without a corresponding increase in Foxp3. These phenotypic changes result from increased signaling through IL-2R. Moreover, myelin oligodendrocyte glycoprotein-specific Kv1.3-KO Th cells can ameliorate experimental autoimmune encephalomyelitis following transfer to wild-type recipients in a manner that is partially dependent on IL-2R and STAT5 signaling. The present study identifies a population of Foxp3(-) T cells with suppressive properties that arises in the absence of Kv1.3 and enhances the understanding of the molecular mechanism by which these cells are generated. This increased understanding could contribute to the development of novel therapies for MS patients that promote heightened immune regulation.
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Affiliation(s)
- Inna V Grishkan
- Department of Neurology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD, USA
| | - Dominique M Tosi
- Department of Neurology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD, USA
| | - Melissa D Bowman
- Department of Neurology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD, USA
| | - Maya Harary
- Department of Neurology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD, USA
| | - Peter A Calabresi
- Department of Neurology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD, USA
| | - Anne R Gocke
- Department of Neurology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD, USA
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24
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Davis LC, Platt FM, Galione A. Preferential Coupling of the NAADP Pathway to Exocytosis in T-Cells. MESSENGER (LOS ANGELES, CALIF. : PRINT) 2015; 4:53-66. [PMID: 27330870 PMCID: PMC4910867 DOI: 10.1166/msr.2015.1040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A cytotoxic T-lymphocyte (CTL) kills an infected or tumorigenic cell by Ca2+-dependent exocytosis of cytolytic granules at the immunological synapse formed between the two cells. However, these granules are more than reservoirs of secretory cytolytic proteins but may also serve as unique Ca2+ signaling hubs that autonomously generate their own signals for exocytosis. This review discusses a selective role for the Ca2+-mobilizing messenger, nicotinic acid adenine dinucleotide phosphate (NAADP) and its molecular targets, two-pore channels (TPCs), in stimulating exocytosis. Given that TPCs reside on the exocytotic granules themselves, these vesicles generate as well as respond to NAADP-dependent Ca2+ signals, which may have wider implications for stimulus-secretion coupling, vesicular fusion, and patho-physiology.
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Affiliation(s)
- Lianne C. Davis
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Frances M. Platt
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
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25
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Hajdu P, Martin GV, Chimote AA, Szilagyi O, Takimoto K, Conforti L. The C-terminus SH3-binding domain of Kv1.3 is required for the actin-mediated immobilization of the channel via cortactin. Mol Biol Cell 2015; 26:1640-51. [PMID: 25739456 PMCID: PMC4436776 DOI: 10.1091/mbc.e14-07-1195] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 02/20/2015] [Indexed: 12/18/2022] Open
Abstract
Polarization of Kv1.3 channels is a necessary step in T-cell activation and motility. Nonetheless, the mechanisms regulating the Kv1.3 channel's membrane movement are not understood. This study provides evidence that cortactin, an actin-binding protein, controls Kv1.3 membrane motility via the channel's SH3 domain. Kv1.3 channels play a pivotal role in the activation and migration of T-lymphocytes. These functions are accompanied by the channels' polarization, which is essential for associated downstream events. However, the mechanisms that govern the membrane movement of Kv1.3 channels remain unclear. F-actin polymerization occurs concomitantly to channel polarization, implicating the actin cytoskeleton in this process. Here we show that cortactin, a factor initiating the actin network, controls the membrane mobilization of Kv1.3 channels. FRAP with EGFP-tagged Kv1.3 channels demonstrates that knocking down cortactin decreases the actin-based immobilization of the channels. Using various deletion and mutation constructs, we show that the SH3 motif of Kv1.3 mediates the channel immobilization. Proximity ligation assays indicate that deletion or mutation of the SH3 motif also disrupts interaction of the channel with cortactin. In T-lymphocytes, the interaction between HS1 (the cortactin homologue) and Kv1.3 occurs at the immune synapse and requires the channel's C-terminal domain. These results show that actin dynamics regulates the membrane motility of Kv1.3 channels. They also provide evidence that the SH3 motif of the channel and cortactin plays key roles in this process.
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Affiliation(s)
- Peter Hajdu
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267 Department of Biophysics and Cell Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - Geoffrey V Martin
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267
| | - Ameet A Chimote
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267
| | - Orsolya Szilagyi
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267 Department of Biophysics and Cell Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - Koichi Takimoto
- Department of Bioengineering and Bioinformatics, Nagaoka University of Technology, Nagaoka 940-2137, Japan
| | - Laura Conforti
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267
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26
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Physiological role of Kv1.3 channel in T lymphocyte cell investigated quantitatively by kinetic modeling. PLoS One 2014; 9:e89975. [PMID: 24594979 PMCID: PMC3940720 DOI: 10.1371/journal.pone.0089975] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 01/23/2014] [Indexed: 11/30/2022] Open
Abstract
Kv1.3 channel is a delayed rectifier channel abundant in human T lymphocytes. Chronic inflammatory and autoimmune disorders lead to the over-expression of Kv1.3 in T cells. To quantitatively study the regulatory mechanism and physiological function of Kv1.3 in T cells, it is necessary to have a precise kinetic model of Kv1.3. In this study, we firstly established a kinetic model capable to precisely replicate all the kinetic features for Kv1.3 channels, and then constructed a T-cell model composed of ion channels including Ca2+-release activated calcium (CRAC) channel, intermediate K+ (IK) channel, TASK channel and Kv1.3 channel for quantitatively simulating the changes in membrane potentials and local Ca2+ signaling messengers during activation of T cells. Based on the experimental data from current-clamp recordings, we successfully demonstrated that Kv1.3 dominated the membrane potential of T cells to manipulate the Ca2+ influx via CRAC channel. Our results revealed that the deficient expression of Kv1.3 channel would cause the less Ca2+ signal, leading to the less efficiency in secretion. This was the first successful attempt to simulate membrane potential in non-excitable cells, which laid a solid basis for quantitatively studying the regulatory mechanism and physiological role of channels in non-excitable cells.
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27
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Martínez-Mármol R, Pérez-Verdaguer M, Roig SR, Vallejo-Gracia A, Gotsi P, Serrano-Albarrás A, Bahamonde MI, Ferrer-Montiel A, Fernández-Ballester G, Comes N, Felipe A. A non-canonical di-acidic signal at the C-terminus of Kv1.3 determines anterograde trafficking and surface expression. J Cell Sci 2013; 126:5681-91. [PMID: 24144698 DOI: 10.1242/jcs.134825] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Impairment of Kv1.3 expression at the cell membrane in leukocytes and sensory neuron contributes to the pathophysiology of autoimmune diseases and sensory syndromes. Molecular mechanisms underlying Kv1.3 channel trafficking to the plasma membrane remain elusive. We report a novel non-canonical di-acidic signal (E483/484) at the C-terminus of Kv1.3 essential for anterograde transport and surface expression. Notably, homologous motifs are conserved in neuronal Kv1 and Shaker channels. Biochemical analysis revealed interactions with the Sec24 subunit of the coat protein complex II. Disruption of this complex retains the channel at the endoplasmic reticulum. A molecular model of the Kv1.3-Sec24a complex suggests salt-bridges between the di-acidic E483/484 motif in Kv1.3 and the di-basic R750/752 sequence in Sec24. These findings identify a previously unrecognized motif of Kv channels essential for their expression on the cell surface. Our results contribute to our understanding of how Kv1 channels target to the cell membrane, and provide new therapeutic strategies for the treatment of pathological conditions.
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Affiliation(s)
- Ramón Martínez-Mármol
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain
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28
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Hajdu P, Chimote AA, Thompson TH, Koo Y, Yun Y, Conforti L. Functionalized liposomes loaded with siRNAs targeting ion channels in effector memory T cells as a potential therapy for autoimmunity. Biomaterials 2013; 34:10249-57. [PMID: 24075407 DOI: 10.1016/j.biomaterials.2013.09.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/05/2013] [Indexed: 12/24/2022]
Abstract
Effector memory T cells (TM) play a key role in the pathology of certain autoimmune disorders. The activity of effector TM cells is under the control of Kv1.3 ion channels, which facilitate the Ca(2+) influx necessary for T cell activation and function, i.e. cytokine release and proliferation. Consequently, the knock-down of Kv1.3 expression in effector TM's may be utilized as a therapy for the treatment of autoimmune diseases. In this study we synthesized lipid unilamellar nanoparticles (NPs) that can selectively deliver Kv1.3 siRNAs into TM cells in vitro. NPs made from a mixture of phosphatidylcholine, pegylated/biotinylated phosphoethanolamine and cholesterol were functionalized with biotinylated-CD45RO (cell surface marker of TM's) antibodies via fluorophore-conjugated streptavidin (CD45RO-NPs). Incubation of T cells with CD45RO-NPs resulted into the selective attachment and endocytosis of the NPs into TM's. Furthermore, the siRNA against Kv1.3, encapsulated into the CD45RO-NPs, was released into the cytosol. Consequently, the expression of Kv1.3 channels decreased significantly in TM's, which led to a remarkable decrease in Ca(2+) influx. Our results can form the basis of an innovative therapeutic approach in autoimmunity.
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Affiliation(s)
- Péter Hajdu
- University of Cincinnati, Department of Internal Medicine, Division of Nephrology and Hypertension, 231 Albert Sabin Way, Cincinnati, OH 45267-0585, USA
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29
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Duque A, Gazula VR, Kaczmarek LK. Expression of Kv1.3 potassium channels regulates density of cortical interneurons. Dev Neurobiol 2013; 73:841-55. [PMID: 23821603 DOI: 10.1002/dneu.22105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 06/19/2013] [Accepted: 06/21/2013] [Indexed: 01/27/2023]
Abstract
The Kv1.3 protein is a member of the large family of voltage-dependent K+ subunits (Kv channels), which assemble to form tetrameric membrane-spanning channels that provide a selective pore for the conductance of K+ across the cell membrane. Kv1.3 differs from most other Kv channels in that deletion of Kv1.3 gene produces very striking changes in development and structure of the olfactory bulb, where Kv1.3 is expressed at high levels, resulting in a lower threshold for detection of odors, an increased number of synaptic glomeruli and alterations in the levels of a variety of neuronal signaling molecules. Because Kv1.3 is also expressed in the cerebral cortex, we have now examined the effects of deletion of the Kv1.3 gene on the expression of interneuron populations of the cerebral cortex. Using unbiased stereology we found an increase in the number of parvalbumin (PV) cells in whole cerebral cortex of Kv1.3-/- mice relative to that in wild-type mice, and a decrease in the number of calbindin (CB), calretinin (CR), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and somatostatin (SOM) interneurons. These changes are accompanied by a decrease in the cortical volume such that the cell density of PV interneurons is significantly increased and that of SOM neurons is decreased in Kv1.3-/- animals. Our studies suggest that, as in the olfactory bulb, Kv1.3 plays a unique role in neuronal differentiation and/or survival of interneuron populations and that expression of Kv1.3 is required for normal cortical function.
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Affiliation(s)
- Alvaro Duque
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut, 06520
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30
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The role of PSD-95 in the rearrangement of Kv1.3 channels to the immunological synapse. Pflugers Arch 2013; 465:1341-53. [PMID: 23553419 DOI: 10.1007/s00424-013-1256-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 02/08/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
Abstract
Establishment of the immunological synapse (IS) between T lymphocytes and antigen-presenting cells is a key step in the adaptive immune response. Several proteins accumulate in the IS, such as the Kv1.3 potassium channel; however, the mechanism of this translocation is unknown. PSD-95 and SAP97 are adaptor proteins that regulate the polarized cell surface expression and localization of Kv1 channels in neurons. We investigated whether these proteins affect the redistribution of Kv1.3 into the IS in non-excitable human T cells. We show here that PSD-95 and SAP97 are expressed in Jurkat and interact with the C terminus of Kv1.3. Disruption of the interaction between PSD-95 or SAP97 and Kv1.3 in Jurkat was realized by the expression of a C-terminal truncated Kv1.3, which lacks the binding domain for these proteins, or by the knockdown of the expression of PSD-95 or SAP97 using specific shRNA. Expression of the truncated Kv1.3 or knockdown of PSD-95, but not the knockdown of SAP97, inhibited the recruitment of Kv1.3 into the IS; the fraction of cells showing polarized Kv1.3 expression upon engagement in an IS was significantly lower than in control cells expressing the full-length Kv1.3, and the rearrangement of Kv1.3 did not show time dependence. In contrast, Jurkat cells expressing the full-length channel showed marked time dependence in the recruitment into the IS peaking at 1 min after the conjugation of the cells. These results demonstrate that PSD-95 participates in the targeting of Kv1.3 into the IS, implying its important role in human T-cell activation.
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31
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Kuras Z, Yun YH, Chimote AA, Neumeier L, Conforti L. KCa3.1 and TRPM7 channels at the uropod regulate migration of activated human T cells. PLoS One 2012; 7:e43859. [PMID: 22952790 PMCID: PMC3428288 DOI: 10.1371/journal.pone.0043859] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 07/30/2012] [Indexed: 11/18/2022] Open
Abstract
The migration of T lymphocytes is an essential part of the adaptive immune response as T cells circulate around the body to carry out immune surveillance. During the migration process T cells polarize, forming a leading edge at the cell front and a uropod at the cell rear. Our interest was in studying the involvement of ion channels in the migration of activated human T lymphocytes as they modulate intracellular Ca(2+) levels. Ca(2+) is a key regulator of cellular motility. To this purpose, we created protein surfaces made of the bio-polymer PNMP and coated with ICAM-1, ligand of LFA-1. The LFA-1 and ICAM-1 interaction facilitates T cell movement from blood into tissues and it is critical in immune surveillance and inflammation. Activated human T lymphocytes polarized and migrated on ICAM-1 surfaces by random walk with a mean velocity of ∼6 µm/min. Confocal microscopy indicated that Kv1.3, CRAC, and TRPM4 channels positioned in the leading-edge, whereas KCa3.1 and TRPM7 channels accumulated in the uropod. The localization of KCa3.1 and TRPM7 at the uropod was associated with oscillations in intracellular Ca(2+) levels that we measured in this cell compartment. Further studies with blockers against Kv1.3 (ShK), KCa3.1 (TRAM-34), CRAC (SKF-96365), TRPM7 (2-APB), and TRPM4 (glibenclamide) indicated that blockade of KCa3.1 and TRPM7, and not Kv1.3, CRAC or TRPM4, inhibits the T cell migration. The involvement of TRPM7 in cell migration was confirmed with siRNAs against TRPM7. Downregulation of TRPM7 significantly reduced the number of migrating T cells and the mean velocity of the migrating T cells. These results indicate that KCa3.1 and TRPM7 selectively localize at the uropod of migrating T lymphocytes and are key components of the T cell migration machinery.
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Affiliation(s)
- Zerrin Kuras
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Yeo-Heung Yun
- Department of Bioengineering, North Carolina Agricultural and Technical State University, Greensboro, North Carolina, United States of America
| | - Ameet A. Chimote
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Lisa Neumeier
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Laura Conforti
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio, United States of America
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32
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Kuras Z, Kucher V, Gordon SM, Neumeier L, Chimote AA, Filipovich AH, Conforti L. Modulation of Kv1.3 channels by protein kinase A I in T lymphocytes is mediated by the disc large 1-tyrosine kinase Lck complex. Am J Physiol Cell Physiol 2012; 302:C1504-12. [PMID: 22378744 DOI: 10.1152/ajpcell.00263.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The cAMP/PKA signaling system constitutes an inhibitory pathway in T cells and, although its biochemistry has been thoroughly investigated, its possible effects on ion channels are still not fully understood. K(V)1.3 channels play an important role in T-cell activation, and their inhibition suppresses T-cell function. It has been reported that PKA modulates K(V)1.3 activity. Two PKA isoforms are expressed in human T cells: PKAI and PKAII. PKAI has been shown to inhibit T-cell activation via suppression of the tyrosine kinase Lck. The aim of this study was to determine the PKA isoform modulating K(V)1.3 and the signaling pathway underneath. 8-Bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP), a nonselective activator of PKA, inhibited K(V)1.3 currents both in primary human T and in Jurkat cells. This inhibition was prevented by the PKA blocker PKI(6-22). Selective knockdown of PKAI, but not PKAII, with siRNAs abolished the response to 8-BrcAMP. Additional studies were performed to determine the signaling pathway mediating PKAI effect on K(V)1.3. Overexpression of a constitutively active mutant of Lck reduced the response of K(V)1.3 to 8-Br-cAMP. Moreover, knockdown of the scaffolding protein disc large 1 (Dlg1), which binds K(V)1.3 to Lck, abolished PKA modulation of K(V)1.3 channels. Immunohistochemistry studies showed that PKAI, but not PKAII, colocalizes with K(V)1.3 and Dlg1 indicating a close proximity between these proteins. These results indicate that PKAI selectively regulates K(V)1.3 channels in human T lymphocytes. This effect is mediated by Lck and Dlg1. We thus propose that the K(V)1.3/Dlg1/Lck complex is part of the membrane pathway that cAMP utilizes to regulate T-cell function.
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Affiliation(s)
- Zerrin Kuras
- Department of Internal Medicine, 231 Albert Sabin Way, University of Cincinnati, Cincinnati, OH 45267-0585, USA
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33
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Martin GV, Yun Y, Conforti L. Modulation of T cell activation by localized K⁺ accumulation at the immunological synapse--a mathematical model. J Theor Biol 2012; 300:173-82. [PMID: 22285786 DOI: 10.1016/j.jtbi.2012.01.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 12/21/2011] [Accepted: 01/11/2012] [Indexed: 01/06/2023]
Abstract
The response of T cells to antigens (T cell activation) is marked by an increase in intracellular Ca²⁺ levels. Voltage-gated and Ca²⁺-dependent K⁺ channels control the membrane potential of human T cells and regulate Ca²⁺ influx. This regulation is dependent on proper accumulation of K⁺ channels at the immunological synapse (IS) a signaling zone that forms between a T cell and antigen presenting cell. It is believed that the IS provides a site for regulation of the activation response and that K⁺ channel inhibition occurs at the IS, but the underlying mechanisms are unknown. A mathematical model was developed to test whether K⁺ efflux through K⁺ channels leads to an accumulation of K⁺ in the IS cleft, ultimately reducing K⁺ channel function and intracellular Ca²⁺ concentration ([Ca²⁺](i)). Simulations were conducted in models of resting and activated T cell subsets, which express different levels of K⁺ channels, by varying the K⁺ diffusion constant and the spatial localization of K⁺ channels at the IS. K⁺ accumulation in the IS cleft was calculated to increase K⁺ concentration ([K⁺]) from its normal value of 5.0 mM to 5.2-10.0 mM. Including K⁺ accumulation in the model of the IS reduced calculated K⁺ current by 1-12% and consequently, reduced calculated [Ca²⁺](i) by 1-28%. Significant reductions in K⁺ current and [Ca²⁺](i) only occurred in activated T cell simulations when most K⁺ channels were centrally clustered at the IS. The results presented show that the localization of K⁺ channels at the IS can produce a rise in [K⁺] in the IS cleft and lead to a substantial decrease in K⁺ currents and [Ca²⁺](i) in activated T cells thus providing a feedback inhibitory mechanism during T cell activation.
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Affiliation(s)
- Geoffrey V Martin
- Department of Internal Medicine, 231 A. Sabin Way, Division of Nephrology, University of Cincinnati, Cincinnati, OH 45267-0585, USA
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34
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Linker for activation of T cells is displaced from lipid rafts and decreases in lupus T cells after activation via the TCR/CD3 pathway. Clin Immunol 2011; 142:243-51. [PMID: 22285373 DOI: 10.1016/j.clim.2011.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 12/19/2011] [Accepted: 12/20/2011] [Indexed: 11/23/2022]
Abstract
Systemic lupus erythematosus (SLE) is characterized by abnormal signal transduction mechanisms in T lymphocytes. Linker for activation of T cells (LAT) couples TCR/CD3 activation with downstream signaling pathways. We reported diminished ERK 1/2 kinase activity in TCR/CD3 stimulated lupus T cells. In this study we evaluated the expression, phosphorylation, lipid raft and immunological synapse (IS) localization and colocalization of LAT with key signalosome molecules. We observed a diminished expression and an abnormal localization of LAT in lipid rafts and at the IS in activated lupus T cells. LAT phosphorylation, capture by GST-Grb2 fusion protein, and coupling to Grb2 and PLCγ1, was similar in healthy control and lupus T cells. Our results suggest that an abnormal localization of LAT within lipid rafts and its accelerated degradation after TCR/CD3 activation may compromise the assembly of the LAT signalosome and downstream signaling pathways required for full MAPK activation in lupus T cells.
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35
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Reneer MC, Estes DJ, Vélez-Ortega AC, Norris A, Mayer M, Marti F. Peripherally induced human regulatory T cells uncouple Kv1.3 activation from TCR-associated signaling. Eur J Immunol 2011; 41:3170-5. [PMID: 21834013 PMCID: PMC3517126 DOI: 10.1002/eji.201141492] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 06/08/2011] [Accepted: 08/08/2011] [Indexed: 11/06/2022]
Abstract
Peripherally induced Tregs (iTregs) are being recognized as a functional and physiologically relevant T-cell subset. Understanding the molecular basis of their development is a necessary step before the therapeutic potential of iTreg manipulation can be exploited. In this study, we report that the differentiation of primary human T cells to suppressor iTregs involves the relocation of key proximal TCR signaling elements to the highly active IL-2-Receptor (IL-2-R) pathway. In addition to the recruitment of lymphocyte-specific protein tyrosine kinase (Lck) to the IL-2-R complex, we identified the dissociation of the voltage-gated K(+) channel Kv1.3 from the TCR pathway and its functional coupling to the IL-2-R. The regulatory switch of Kv1.3 activity in iTregs may constitute an important contributing factor in the signaling rewiring associated with the development of peripheral human iTregs and sheds new light upon the reciprocal crosstalk between the TCR and the IL-2-R pathways.
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Affiliation(s)
- Mary Catherine Reneer
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Daniel J. Estes
- Department of Biomedical Engineering and Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109
| | - Alejandra Catalina Vélez-Ortega
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Andrea Norris
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Michael Mayer
- Department of Biomedical Engineering and Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109
| | - Francesc Marti
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky 40536
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36
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Influence of specific immunotherapy on the activity of human T lymphocyte Kv1.3 voltage-gated potassium channels in insect venom allergic patients. J Membr Biol 2011; 242:23-9. [PMID: 21706208 DOI: 10.1007/s00232-011-9373-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 06/03/2011] [Indexed: 10/18/2022]
Abstract
Kv1.3 channels play an important role in T lymphocytes function. CD4(+) and CD4(+)CD25(+) T cells are two broad categories of T cells that are critically involved in the immunoresponse to allergens and that are also a major target for allergen immunotherapy. The aim of the study was to evaluate the effects of venom immunotherapy (VIT) on the activity of Kv1.3. channels on noncultured subsets: CD4(+) and CD4(+)CD25(+) T cells of insect venom allergic patients. Eleven patients with allergic reactions to bee or wasp venoms participated in the study. The patients were provided VIT according to the ultrarush protocol. CD4(+) and CD4(+)CD25(+) T cells were isolated from peripheral blood mononuclear cells of VIT-treated patients by an immunomagnetic method. We used the whole-cell patch clamp technique to investigate the whole potassium chord conductance (gK) of Kv1.3. channels in CD4(+) and CD4(+)CD25(+) T cells of venom-sensitive patients before and during the course of VIT. The conductance of Kv1.3. channels on CD4(+)CD25(+) T cells decreased during the course of VIT. On day 0 it was 0.054 ± 0.07 [nS], and on day 70 it was 0.008 ± 0.09 [nS] (P = 0.03). The observed decrease of the gK of the Kv1.3 channels in the subpopulation of activated T cells may contribute to T cell tolerance and functional unresponsiveness of these cells to allergen in the early stages of VIT.
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Felipe A, Soler C, Comes N. Kv1.5 in the immune system: the good, the bad, or the ugly? Front Physiol 2010; 1:152. [PMID: 21423392 PMCID: PMC3059964 DOI: 10.3389/fphys.2010.00152] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/28/2010] [Indexed: 11/13/2022] Open
Abstract
For the last 20 years, knowledge of the physiological role of voltage-dependent potassium channels (Kv) in the immune system has grown exponentially. Leukocytes express a limited repertoire of Kv channels, which contribute to the membrane potential. These proteins are involved in the immune response and are therefore considered good pharmacological targets. Although there is a clear consensus about the physiological relevance of Kv1.3, the expression and the role of Kv1.5 are controversial. However, recent reports indicate that certain heteromeric Kv1.3/Kv1.5 associations may provide insight on Kv1.5. Here, we summarize what is known about this issue and highlight the role of Kv1.5 partnership interactions that could be responsible for this debate. The Kv1.3/Kv1.5 heterotetrameric composition of the channel and their possible differential associations with accessory regulatory proteins warrant further investigation.
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Affiliation(s)
- Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina, Universitat de Barcelona Barcelona, Spain.
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38
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Krummel MF, Cahalan MD. The immunological synapse: a dynamic platform for local signaling. J Clin Immunol 2010; 30:364-72. [PMID: 20390326 PMCID: PMC2874029 DOI: 10.1007/s10875-010-9393-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 03/16/2010] [Indexed: 01/06/2023]
Abstract
The immunological synapse (IS) as a concept has evolved from a static view of the junction between T cells and their antigen-presenting cell partners. The entire process of IS formation and extinction is now known to entail a dynamic reorganization of membrane domains and proteins within and adjacent to those domains. Discussion The entire process is also intricately tied to the motility machinery—both as that machinery directs “scanning” prior to T-cell receptor engagement and as it is appropriated during the ongoing developments at the IS. While the synapse often remains dynamic in order to encourage surveillance of new antigen-presenting surfaces, cytoskeletal forces also regulate the development of signals, likely including the assembly of ion channels. In both neuronal and immunological synapses, localized Ca2+ signals and accumulation or depletion of ions in microdomains accompany the concentration of signaling molecules in the synapse. Such spatiotemporal signaling in the synapse greatly accelerates kinetics and provides essential checkpoints to validate effective cell–cell communication.
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Affiliation(s)
- Matthew F Krummel
- Department of Pathology, University of California San Francisco, 513 Parnassus Avenue HSW-0511, San Francisco, CA 94143, USA.
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39
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Bittner S, Bobak N, Herrmann AM, Göbel K, Meuth P, Höhn KG, Stenner MP, Budde T, Wiendl H, Meuth SG. Upregulation of K2P5.1 potassium channels in multiple sclerosis. Ann Neurol 2010; 68:58-69. [PMID: 20582984 DOI: 10.1002/ana.22010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Activation of T cells critically depends on potassium channels. We here characterize the impact of K(2P)5.1 (KCNK5; TASK2), a member of the 2-pore domain family of potassium channels, on T-cell function and demonstrate its putative relevance in a T-cell-mediated autoimmune disorder, multiple sclerosis (MS). METHODS Expression of K(2P)5.1 was investigated on RNA and protein level in different immune cells and in MS patients' biospecimens (peripheral blood mononuclear cells, cerebrospinal fluid cells, brain tissue specimen). Functional consequences of K(2P)5.1 expression were analyzed using pharmacological modulation, small interfering RNA (siRNA), overexpression, electrophysiological recordings, and computer modeling. RESULTS Human T cells constitutively express K(2P)5.1. After T-cell activation, a significant and time-dependent upregulation of K(2P)5.1 channel expression was observed. Pharmacological blockade of K(2P)5.1 or knockdown with siRNA resulted in reduced T-cell functions, whereas overexpression of K(2P)5.1 had the opposite effect. Electrophysiological recordings of T cells clearly dissected K(2P)5.1-mediated effects from other potassium channels. The pathophysiological relevance of these findings was demonstrated by a significant K(2P)5.1 upregulation in CD4(+) and CD8(+) T cells in relapsing/remitting MS (RRMS) patients during acute relapses as well as higher levels on CD8(+) T cells of clinically isolated syndrome, RRMS, and secondary progressive multiple sclerosis patients during clinically stable disease. T cells in the cerebrospinal fluid from MS patients exhibit significantly elevated K(2P)5.1 levels. Furthermore, K(2P)5.1-positive T cells can be found in inflammatory lesions in MS tissue specimens. INTERPRETATION Selective targeting of K(2P)5.1 may hold therapeutic promise for MS and putatively other T-cell-mediated disorders.
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Affiliation(s)
- Stefan Bittner
- Department of Neurology, University of Würzburg, Würzburg, Münster, Germany
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40
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Varga Z, Hajdu P, Panyi G. Ion channels in T lymphocytes: An update on facts, mechanisms and therapeutic targeting in autoimmune diseases. Immunol Lett 2010; 130:19-25. [DOI: 10.1016/j.imlet.2009.12.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 12/08/2009] [Accepted: 12/10/2009] [Indexed: 12/31/2022]
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Jury EC, Flores-Borja F, Kalsi HS, Lazarus M, Isenberg DA, Mauri C, Ehrenstein MR. Abnormal CTLA-4 function in T cells from patients with systemic lupus erythematosus. Eur J Immunol 2010; 40:569-78. [PMID: 19950182 DOI: 10.1002/eji.200939781] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
CTLA-4 is a critical gatekeeper of T-cell activation and immunological tolerance and has been implicated in patients with a variety of autoimmune diseases through genetic association. Since T cells from patients with the autoimmune disease systemic lupus erythematosus (SLE) display a characteristic hyperactive phenotype, we investigated the function of CTLA-4 in SLE. Our results reveal increased CTLA-4 expression in FOXP3(-) responder T cells from patients with SLE compared with other autoimmune rheumatic diseases and healthy controls. However, CTLA-4 was unable to regulate T-cell proliferation, lipid microdomain formation and phosphorylation of TCR-zeta following CD3/CD28 co-stimulation, in contrast to healthy T cells. Although lupus T cells responded in vitro to CD3/CD28 co-stimulation, there was no parallel increase in CTLA-4 expression, which would normally provide a break on T-cell proliferation. These defects were associated with exclusion of CTLA-4 from lipid microdomains providing an anatomical basis for its loss of function. Collectively our data identify CTLA-4 dysfunction as a potential cause for abnormal T-cell activation in patients with SLE, which could be targeted for therapy.
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Affiliation(s)
- Elizabeth C Jury
- Department of Medicine, Centre for Rheumatology, University College London, London, UK.
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Nicolaou SA, Neumeier L, Takimoto K, Lee SM, Duncan HJ, Kant SK, Mongey AB, Filipovich AH, Conforti L. Differential calcium signaling and Kv1.3 trafficking to the immunological synapse in systemic lupus erythematosus. Cell Calcium 2009; 47:19-28. [PMID: 19959227 DOI: 10.1016/j.ceca.2009.11.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 10/27/2009] [Accepted: 11/02/2009] [Indexed: 11/24/2022]
Abstract
Systemic lupus erythematosus (SLE) T cells exhibit several activation signaling anomalies including defective Ca(2+) response and increased NF-AT nuclear translocation. The duration of the Ca(2+) signal is critical in the activation of specific transcription factors and a sustained Ca(2+) response activates NF-AT. Yet, the distribution of Ca(2+) responses in SLE T cells is not known. Furthermore, the mechanisms responsible for Ca(2+) alterations are not fully understood. Kv1.3 channels control Ca(2+) homeostasis in T cells. We reported a defect in Kv1.3 trafficking to the immunological synapse (IS) of SLE T cells that might contribute to the Ca(2+) defect. The present study compares single T cell quantitative Ca(2+) responses upon formation of the IS in SLE, normal, and rheumatoid arthritis (RA) donors. Also, we correlated cytosolic Ca(2+) concentrations and Kv1.3 trafficking in the IS by two-photon microscopy. We found that sustained [Ca(2+)](i) elevations constitute the predominant response to antigen stimulation of SLE T cells. This defect is selective to SLE as it was not observed in RA T cells. Further, we observed that in normal T cells termination of Ca(2+) influx is accompanied by Kv1.3 permanence in the IS, while Kv1.3 premature exit from the IS correlates with sustained Ca(2+) responses in SLE T cells. Thus, we propose that Kv1.3 trafficking abnormalities contribute to the altered distribution in Ca(2+) signaling in SLE T cells. Overall these defects may explain in part the T cell hyperactivity and dysfunction documented in SLE patients.
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Affiliation(s)
- Stella A Nicolaou
- Department of Internal Medicine, University of Cincinnati, OH 45267, USA
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43
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Nicolaou SA, Neumeier L, Steckly A, Kucher V, Takimoto K, Conforti L. Localization of Kv1.3 channels in the immunological synapse modulates the calcium response to antigen stimulation in T lymphocytes. THE JOURNAL OF IMMUNOLOGY 2009; 183:6296-302. [PMID: 19841189 DOI: 10.4049/jimmunol.0900613] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The immunological synapse (IS), a highly organized structure that forms at the point of contact between a T cell and an APC, is essential for the proper development of signaling events, including the Ca(2+) response. Kv1.3 channels control Ca(2+) homeostasis in human T cells and move into the IS upon Ag presentation. However, the process involved in channel accumulation in the IS and the functional implications of this localization are not yet known. Here we define the movement of Kv1.3 into the IS and study whether Kv1.3 localization into the IS influences Ca(2+) signaling in Jurkat T cells. Crosslinking of the channel protein with an extracellular Ab limits Kv1.3 mobility and accumulation at the IS. Moreover, Kv1.3 recruitment to the IS does not involve the transport of newly synthesized channels and it does not occur through recycling of membrane channels. Kv1.3 localization in the IS modulates the Ca(2+) response. Blockade of Kv1.3 movement into the IS by crosslinking significantly increases the amplitude of the Ca(2+) response triggered by anti-CD3/anti-CD28-coated beads, which induce the formation of the IS. On the contrary, the Ca(2+) response induced by TCR stimulation without the formation of the IS with soluble anti-CD3/anti-CD28 Abs is unaltered. The results presented herein indicate that, upon Ag presentation, membrane-incorporated Kv1.3 channels move along the plasma membrane to localize in the IS. This localization is important to control the amplitude of the Ca(2+) response, and disruption of this process can account for alterations of downstream Ca(2+)-dependent signaling events.
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Affiliation(s)
- Stella A Nicolaou
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
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Kummerow C, Junker C, Kruse K, Rieger H, Quintana A, Hoth M. The immunological synapse controls local and global calcium signals in T lymphocytes. Immunol Rev 2009; 231:132-47. [DOI: 10.1111/j.1600-065x.2009.00811.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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45
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Varga Z, Csepany T, Papp F, Fabian A, Gogolak P, Toth A, Panyi G. Potassium channel expression in human CD4+ regulatory and naïve T cells from healthy subjects and multiple sclerosis patients. Immunol Lett 2009; 124:95-101. [DOI: 10.1016/j.imlet.2009.04.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 04/17/2009] [Accepted: 04/23/2009] [Indexed: 10/20/2022]
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46
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Tóth A, Szilágyi O, Krasznai Z, Panyi G, Hajdú P. Functional consequences of Kv1.3 ion channel rearrangement into the immunological synapse. Immunol Lett 2009; 125:15-21. [PMID: 19477198 DOI: 10.1016/j.imlet.2009.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 05/12/2009] [Accepted: 05/16/2009] [Indexed: 01/29/2023]
Abstract
Formation of immunological synapse (IS), the interface between T cells and antigen presenting cells, is a crucial step in T cell activation. This conjugation formation results in the rearrangement and segregation of a set of membrane bound and cytosolic proteins, including that of the T cell receptor, into membrane domains. It was showed earlier that Kv1.3, the dominant voltage-gated potassium channel of T cells redistributes into the IS on interaction with its specific APC. In the present experiments we investigated the functional consequences of the translocation of Kv1.3 channels into the IS formed between mouse helper T (T(h)2) and B cells. Biophysical characteristics of whole-cell Kv1.3 current in standalone cells (c) or ones in IS (IS) were determined using voltage-clamp configuration of standard whole-cell patch-clamp technique. Patch-clamp recordings showed that the activation of Kv1.3 current slowed (tau(a,IS)=2.36+/-0.13 ms (n=7); tau(a,c)=1.36+/-0.06 ms (n=18)) whereas the inactivation rate increased (tau(i,IS)=263+/-29 ms (n=7); tau(i,c)=365+/-27 ms (n=17)) in cells being in IS compared to the standalone cells. The equilibrium distribution between the open and the closed states of Kv1.3 (voltage-dependence of steady-state activation) was shifted toward the depolarizing potentials in T cells engaged into IS (V(1/2,IS)=-20.9+/-2 mV (n=7), V(1/2,c)=-26.4+/-1.5 mV (n=12)). Thus, segregation of Kv1.3 channels into the IS modifies the gating properties of the channels. Application of protein kinase (PK) inhibitors (PKC: GF109203X, PKA: H89, p56Lck: damnacanthal) demonstrated that increase in the inactivation rate can be explained by the dephosphorylation of the channel protein. However, the slower activation kinetics of Kv1.3 in IS is likely to be the consequence of the redistribution of the channels into distinct membrane domains.
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Affiliation(s)
- Agnes Tóth
- Department of Biophysics and Cell Biology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
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Engagement of the CD4 receptor affects the redistribution of Lck to the immunological synapse in primary T cells: implications for T-cell activation during human immunodeficiency virus type 1 infection. J Virol 2008; 83:1193-200. [PMID: 19019957 DOI: 10.1128/jvi.01023-08] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Understanding the molecular mechanisms underlying dysregulated immune responses in human immunodeficiency virus type 1 (HIV-1) infection is crucial for the control of HIV/AIDS. Despite the postulate that HIV envelope glycoprotein gp120-CD4 interactions lead to impaired T-cell responses, the precise mechanisms underlying such association are not clear. To address this, we analyzed Lck and F-actin redistribution into the immunological synapse in stimulated human primary CD4(+) T cells from HIV-1-infected donors. Similar experiments were performed with CD4(+) T cells from HIV-uninfected donors, which were exposed to anti-CD4 domain 1 antibodies, as an in vitro model of gp120-CD4 interactions, or aldithriol-inactivated HIV-1 virions before stimulation. CD4(+) T cells from HIV-infected patients exhibited a two- to threefold inhibition of both Lck and F-actin recruitment into the synapse, compared to cells from uninfected donors. Interestingly, defective recruitment of Lck was ameliorated following suppressive highly active antiretroviral therapy. Engagement of the CD4 receptor on T cells from HIV-uninfected donors before anti-CD3/CD28 stimulation led to similar defects. Furthermore, the redistribution of Lck into lipid rafts was abrogated by CD4 preengagement. Our results suggest that the engagement of CD4 by HIV gp120 prior to T-cell receptor stimulation leads to dysregulation of early signaling events and could consequently play an important role in impaired CD4(+) T-cell function.
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Poulopoulou C, Papadopoulou-Daifoti Z, Hatzimanolis A, Fragiadaki K, Polissidis A, Anderzanova E, Davaki P, Katsiari CG, Sfikakis PP. Glutamate levels and activity of the T cell voltage-gated potassium Kv1.3 channel in patients with systemic lupus erythematosus. ACTA ACUST UNITED AC 2008; 58:1445-50. [DOI: 10.1002/art.23446] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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49
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Tsokos GC. Calcium signaling in systemic lupus erythematosus lymphocytes and its therapeutic exploitation. ACTA ACUST UNITED AC 2008; 58:1216-9. [DOI: 10.1002/art.23445] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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