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Guo Y, Zhu W, Yuan P, Huang X, Lu S, Cao Z, Zhao X, Wu Y. Similar neurotoxin expression profiles of traditional Chinese scorpion medicine material between juvenile and adult Mesobuthus martensii scorpions revealed by multiple strategic proteomics. JOURNAL OF ETHNOPHARMACOLOGY 2024; 332:118338. [PMID: 38759762 DOI: 10.1016/j.jep.2024.118338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/30/2024] [Accepted: 05/10/2024] [Indexed: 05/19/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The Mesobuthus martensii scorpions, called as "Quanxie", are known Chinese medicinal material base on the "Combat poison with poison" strategy for more than one thousand years, and still widely used to treat various diseases according to the Pharmacopoeia of the People's Republic of China nowadays. AIM OF STUDY The study aims to investigate the similarity of scorpion neurotoxins at the protein level between the juvenile and adult Mesobuthus martensii scorpions as Chinese medicine materials. MATERIALS AND METHODS The second-, third- and fourth-instar, and adult Mesobuthus martensii scorpions were collected for the characterization of neurotoxin expression through multiple strategic proteomics, including undigested scorpion venom, endopeptidase-digested, and undigested scorpion telson extract for the sample analysis. RESULTS Based on the known 107 scorpion neurotoxins from the genomic and transcriptomic analysis of adult Mesobuthus martensii scorpions, the multiple strategic proteomics first revealed that neurotoxins exhibited more stability in telson extract than secreted venom. In the reported transcripts of scorpion neurotoxins, approximately 53%, 56%, 66% and 78% of neurotoxins were detected through undigested scorpion venom, the endopeptidase Arg-C-, Lys-C-digested telson extract, and undigested telson extract strategies, respectively. Nearly 79% of scorpion neurotoxins detected in third-instar Mesobuthus martensii scorpions represent the largest number of scorpion neurotoxins from proteomic analysis to date. Moreover, a total of 84% of scorpion neurotoxins were successfully identified at the protein level, and similar neurotoxin expression profiles in second-, third- and fourth-instar, and adult Mesobuthus martensii scorpions were first revealed by the multiple strategic proteomics. CONCLUSION These findings for the first time demonstrate the similar neurotoxin expression profiles between the juvenile and adult Mesobuthus martensii scorpions as Chinese medicinal material, which would serve as a paradigm for further toxin analysis from different venomous animals.
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Affiliation(s)
- Yiyuan Guo
- College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Wenzhuo Zhu
- College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Peixin Yuan
- College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xin Huang
- College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Sijia Lu
- College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Zhijian Cao
- College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xiaolu Zhao
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Yingliang Wu
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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Chandy KG, Sanches K, Norton RS. Structure of the voltage-gated potassium channel K V1.3: Insights into the inactivated conformation and binding to therapeutic leads. Channels (Austin) 2023; 17:2253104. [PMID: 37695839 PMCID: PMC10496531 DOI: 10.1080/19336950.2023.2253104] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/13/2023] Open
Abstract
The voltage-gated potassium channel KV1.3 is an important therapeutic target for the treatment of autoimmune and neuroinflammatory diseases. The recent structures of KV1.3, Shaker-IR (wild-type and inactivating W434F mutant) and an inactivating mutant of rat KV1.2-KV2.1 paddle chimera (KVChim-W362F+S367T+V377T) reveal that the transition of voltage-gated potassium channels from the open-conducting conformation into the non-conducting inactivated conformation involves the rupture of a key intra-subunit hydrogen bond that tethers the selectivity filter to the pore helix. Breakage of this bond allows the side chains of residues at the external end of the selectivity filter (Tyr447 and Asp449 in KV1.3) to rotate outwards, dilating the outer pore and disrupting ion permeation. Binding of the peptide dalazatide (ShK-186) and an antibody-ShK fusion to the external vestibule of KV1.3 narrows and stabilizes the selectivity filter in the open-conducting conformation, although K+ efflux is blocked by the peptide occluding the pore through the interaction of ShK-Lys22 with the backbone carbonyl of KV1.3-Tyr447 in the selectivity filter. Electrophysiological studies on ShK and the closely-related peptide HmK show that ShK blocks KV1.3 with significantly higher potency, even though molecular dynamics simulations show that ShK is more flexible than HmK. Binding of the anti-KV1.3 nanobody A0194009G09 to the turret and residues in the external loops of the voltage-sensing domain enhances the dilation of the outer selectivity filter in an exaggerated inactivated conformation. These studies lay the foundation to further define the mechanism of slow inactivation in KV channels and can help guide the development of future KV1.3-targeted immuno-therapeutics.
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Affiliation(s)
- K. George Chandy
- LKCMedicine-ICESing Ion Channel Platform, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Karoline Sanches
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria, Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria, Australia
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Chioccioli Altadonna G, Montalbano A, Iorio J, Becchetti A, Arcangeli A, Duranti C. The Interaction between hERG1 and β1 Integrins Modulates hERG1 Current in Different Pathological Cell Models. MEMBRANES 2022; 12:1162. [PMID: 36422154 PMCID: PMC9698864 DOI: 10.3390/membranes12111162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/13/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
Ion channels are implicated in various diseases, including cancer, in which they modulate different aspects of cancer progression. In particular, potassium channels are often aberrantly expressed in cancers, a major example being provided by hERG1. The latter is generally complexed with β1 integrin in tumour cells, and such a molecular complex represents a new druggable hub. The present study focuses on the characterization of the functional consequences of the interaction between hERG1 and β1 integrins on different substrates over time. To this purpose, we studied the interplay alteration on the plasma membrane through patch clamp techniques in a cellular model consisting of human embryonic kidney (HEK) cells stably transfected with hERG1 and in a cancer cell model consisting of SH-SY5Y neuroblastoma cells, endogenously expressing the channel. Cells were seeded on different substrates known to stimulate β1 integrins, such as fibronectin (FN) for HEK-hERG1 and laminin (LMN) for SH-SY5Y. In HEK cells stably overexpressing hERG1, we observed a hERG1 current density increase accompanied by Vrest hyperpolarization after cell seeding onto FN. Notably, a similar behaviour was shown by SH-SY5Y neuroblastoma cells plated onto LMN. Interestingly, we did not observe this phenomenon when plating the cells on substrates such as Bovine Serum Albumin (BSA) or Polylysine (PL), thus suggesting a crucial involvement of ECM proteins as well as of β1 integrin activation.
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Affiliation(s)
| | - Alberto Montalbano
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Jessica Iorio
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Annarosa Arcangeli
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Claudia Duranti
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
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Selvakumar P, Fernández-Mariño AI, Khanra N, He C, Paquette AJ, Wang B, Huang R, Smider VV, Rice WJ, Swartz KJ, Meyerson JR. Structures of the T cell potassium channel Kv1.3 with immunoglobulin modulators. Nat Commun 2022; 13:3854. [PMID: 35788586 PMCID: PMC9253088 DOI: 10.1038/s41467-022-31285-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 06/07/2022] [Indexed: 11/09/2022] Open
Abstract
The Kv1.3 potassium channel is expressed abundantly on activated T cells and mediates the cellular immune response. This role has made the channel a target for therapeutic immunomodulation to block its activity and suppress T cell activation. Here, we report structures of human Kv1.3 alone, with a nanobody inhibitor, and with an antibody-toxin fusion blocker. Rather than block the channel directly, four copies of the nanobody bind the tetramer's voltage sensing domains and the pore domain to induce an inactive pore conformation. In contrast, the antibody-toxin fusion docks its toxin domain at the extracellular mouth of the channel to insert a critical lysine into the pore. The lysine stabilizes an active conformation of the pore yet blocks ion permeation. This study visualizes Kv1.3 pore dynamics, defines two distinct mechanisms to suppress Kv1.3 channel activity with exogenous inhibitors, and provides a framework to aid development of emerging T cell immunotherapies.
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Affiliation(s)
- Purushotham Selvakumar
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - Ana I Fernández-Mariño
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Nandish Khanra
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - Changhao He
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - Alice J Paquette
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY, USA
| | - Bing Wang
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY, USA
| | - Ruiqi Huang
- Applied Biomedical Science Institute, San Diego, CA, USA
- Minotaur Therapeutics, San Diego, CA, USA
| | - Vaughn V Smider
- Applied Biomedical Science Institute, San Diego, CA, USA
- Minotaur Therapeutics, San Diego, CA, USA
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - William J Rice
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY, USA
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Joel R Meyerson
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA.
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Phan HTL, Kim HJ, Jo S, Kim WK, Namkung W, Nam JH. Anti-Inflammatory Effect of Licochalcone A via Regulation of ORAI1 and K + Channels in T-Lymphocytes. Int J Mol Sci 2021; 22:ijms221910847. [PMID: 34639190 PMCID: PMC8509259 DOI: 10.3390/ijms221910847] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/02/2021] [Accepted: 10/04/2021] [Indexed: 02/07/2023] Open
Abstract
Calcium signaling plays a vital role in the regulation of various cellular processes, including activation, proliferation, and differentiation of T-lymphocytes, which is mediated by ORAI1 and potassium (K+) channels. These channels have also been identified as highly attractive therapeutic targets for immune-related diseases. Licochalcone A is a licorice-derived chalconoid known for its multifaceted beneficial effects in pharmacological treatments, including its anti-inflammatory, anti-asthmatic, antioxidant, antimicrobial, and antitumorigenic properties. However, its anti-inflammatory effects involving ion channels in lymphocytes remain unclear. Thus, the present study aimed to investigate whether licochalcone A inhibits ORAI1 and K+ channels in T-lymphocytes. Our results indicated that licochalcone A suppressed all three channels (ORAI1, Kv1.3, and KCa3.1) in a concentration-dependent matter, with IC50 values of 2.97 ± 1.217 µM, 0.83 ± 1.222 µM, and 11.21 ± 1.07 µM, respectively. Of note, licochalcone A exerted its suppressive effects on the IL-2 secretion and proliferation in CD3 and CD28 antibody-induced T-cells. These results indicate that the use of licochalcone A may provide an effective treatment strategy for inflammation-related immune diseases.
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Affiliation(s)
- Hong T. L. Phan
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Korea; (H.J.K.); (W.K.K.)
| | - Hyun J. Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Korea; (H.J.K.); (W.K.K.)
| | - Sungwoo Jo
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, 85 Songdogwahak-ro, Incheon 21983, Korea;
| | - Woo K. Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Korea; (H.J.K.); (W.K.K.)
- Department of Internal Medicine Graduate School of Medicine, Dongguk University, 27 Dongguk-ro, Goyang 10326, Korea
| | - Wan Namkung
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, 85 Songdogwahak-ro, Incheon 21983, Korea;
- Correspondence: (W.N.); (J.H.N.)
| | - Joo H. Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Korea; (H.J.K.); (W.K.K.)
- Correspondence: (W.N.); (J.H.N.)
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Qin C, Wan X, Li S, Yang F, Yang L, Zuo Z, Cao Z, Chen Z, Wu Y. Different pharmacological properties between scorpion toxin BmKcug2 and its degraded analogs highlight the diversity of K + channel blockers from thermally processed scorpions. Int J Biol Macromol 2021; 178:143-153. [PMID: 33636268 DOI: 10.1016/j.ijbiomac.2021.02.155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/16/2021] [Accepted: 02/20/2021] [Indexed: 11/16/2022]
Abstract
Novel degraded potassium channel-modulatory peptides were recently found in thermally processed scorpions, but their pharmacological properties remain unclear. Here, we identified a full-length scorpion toxin (i.e., BmKcug2) and its four truncated analogs (i.e., BmKcug2-P1, BmKcug2-P2, BmKcug2-P3 and BmKcug2-P4) with three conserved disulfide bonds in processed scorpion medicinal material by mass spectrometry. The pharmacological experiments revealed that the recombinant BmKcug2 and BmKcug2-P1 could selectively inhibit the human Kv1.2 and human Kv1.3 potassium channels, while the other three analogs showed a much weaker inhibitory effect on potassium channels. BmKcug2 inhibited hKv1.2 and hKv1.3 channels, with IC50 values of 45.6 ± 5.8 nM and 215.2 ± 39.7 nM, respectively, and BmKcug2-P1 inhibited hKv1.2 and hKv1.3, with IC50 values of 89.9 ± 9.6 nM and 1142.4 ± 64.5 nM, respectively. The chromatographic analysis and pharmacological properties of BmKcug2 and BmKcug2-P1 boiled in water for different times further strongly supported their good thermal stability. Structural and functional dissection indicated that one amino acid, i.e., Tyr36, determined the differential affinities of BmKcug2 and four BmKcug2 analogs. Altogether, this research investigated the different pharmacological properties of BmKcug2 and its truncated analogs, and the findings highlighted the diversity of K+ channel blockers from various scorpion species through thermal processing.
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Affiliation(s)
- Chenhu Qin
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiuping Wan
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Songryong Li
- College of Life Sciences, Wuhan University, Wuhan 430072, China; Department of Biotechnology, Institute for Life Science, Kim Hyong Jik University of Education, Pyongyang, Democratic People's Republic of Korea
| | - Fan Yang
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Liuting Yang
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zheng Zuo
- Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Zhijian Cao
- College of Life Sciences, Wuhan University, Wuhan 430072, China; Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Zongyun Chen
- College of Life Sciences, Wuhan University, Wuhan 430072, China; Department of Biochemistry and Molecular Biology, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China
| | - Yingliang Wu
- College of Life Sciences, Wuhan University, Wuhan 430072, China; Center for BioDrug Research, Wuhan University, Wuhan 430072, China.
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Lissabet JFB, Belén LH, Farias JG. PPLK +C: A Bioinformatics Tool for Predicting Peptide Ligands of Potassium Channels Based on Primary Structure Information. Interdiscip Sci 2020; 12:258-263. [PMID: 31912313 DOI: 10.1007/s12539-019-00356-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 12/22/2019] [Accepted: 12/24/2019] [Indexed: 10/25/2022]
Abstract
Potassium channels play a key role in regulating the flow of ions through the plasma membrane, orchestrating many cellular processes including cell volume regulation, hormone secretion and electrical impulse formation. Ligand peptides of potassium channels are molecules used in basic and applied research and are now considered promising alternatives in the treatment of many diseases, such as cardiovascular diseases and cancer. Currently, there are various bioinformatics tools focused on the prediction of peptides with different activities. However, none of the current tools can predict ligand peptides of potassium channels. In this work, we developed a tool called PPLK+C; this is the first tool that can predict peptide ligands of potassium channels. We also evaluated several amino acid molecular features and four machine-learning algorithms for the prediction of potassium channel ligand peptides: random forest, nearest neighbors, support vector machine and artificial neural network. All the biological data used in this study for training and validating models were obtained from peptides with experimentally verified activity. PPLK+C is a bioinformatics software written in the Python programming language, which showed a high predictive capacity with a model generated with the random forest algorithm: 0.77 sensitivity, 0.94 specificity, 0.91 accuracy and 0.70 Matthews correlation coefficient. PPLK+C is a novel tool with a friendly interface that can be used for the discovery of novel ligand peptides of potassium channels with high reliability, using only primary structure information.
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Affiliation(s)
- Jorge Félix Beltrán Lissabet
- Department of Chemical Engineering, Faculty of Engineering and Sciences, Universidad de La Frontera, Av. Francisco Salazar 01145, P.O. Box 54-D, 4811230, Temuco, Chile
| | - Lisandra Herrera Belén
- Department of Chemical Engineering, Faculty of Engineering and Sciences, Universidad de La Frontera, Av. Francisco Salazar 01145, P.O. Box 54-D, 4811230, Temuco, Chile
| | - Jorge G Farias
- Department of Chemical Engineering, Faculty of Engineering and Sciences, Universidad de La Frontera, Av. Francisco Salazar 01145, P.O. Box 54-D, 4811230, Temuco, Chile.
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Ye CJ, Li SA, Zhang Y, Lee WH. Geraniol targets K V1.3 ion channel and exhibits anti-inflammatory activity in vitro and in vivo. Fitoterapia 2019; 139:104394. [PMID: 31669719 DOI: 10.1016/j.fitote.2019.104394] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/15/2019] [Accepted: 10/20/2019] [Indexed: 01/18/2023]
Abstract
Naturally occurring monoterpenes are known for their various pharmacological activities including anti-inflammation. KV1.3 ion channel is a voltage-gated potassium channel and has been validated as a drug target for autoimmune and chronic inflammatory diseases like psoriasis. Here we experimentally test the direct interaction between monoterpenes and KV1.3 ion channel. Our electrophysiological analysis determined that monoterpenes (geraniol, nerol, β-citronellol, citral and linalool) have inhibitory effects on KV1.3 ion channel. Representatively, geraniol reversibly blocked KV1.3 currents in a voltage-dependent manner with an IC50 of 490.50 ± 1.04 μM at +40 mV in HEK293T cells. At the effective concentrations, geraniol also inhibited cytokine secretion of activated human T cells, including IL-2, TNF-α and IFN-γ. In an imiquimod-induced psoriasis-like animal model, geraniol administration significantly reduced psoriasis area and severity index scores, ameliorated the deteriorating histopathology and decreased the degree of splenomegaly. Together, our findings not only suggest that monoterpenes may serve as lead molecules for the development of KV1.3 inhibitors, but also indicate that geraniol could be considered as a promising therapeutic candidate to treat autoimmune diseases.
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Affiliation(s)
- Chen-Jun Ye
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences, Key Laboratory of bioactive peptides of Yunnan Province, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Sheng-An Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences, Key Laboratory of bioactive peptides of Yunnan Province, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Yun Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences, Key Laboratory of bioactive peptides of Yunnan Province, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
| | - Wen-Hui Lee
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences, Key Laboratory of bioactive peptides of Yunnan Province, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
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Imura N, Ae M, Hoshino R, Abe M, Yamamuro T, Oyama K, Oyama Y. Membrane hyperpolarization and depolarization of rat thymocytes by azoxystrobin, a post harvest fungicide. Chem Biol Interact 2019; 300:35-39. [DOI: 10.1016/j.cbi.2019.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/30/2018] [Accepted: 01/06/2019] [Indexed: 12/18/2022]
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10
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Funakoshi Y, Azuma A, Ishikawa M, Itsuki S, Tamura Y, Kanemaru K, Hirai S, Oyama Y. Cytometrical analysis of the adverse effects of indican, indoxyl, indigo, and indirubin on rat thymic lymphocytes. Toxicol Res (Camb) 2018; 7:513-520. [PMID: 30090601 PMCID: PMC6062345 DOI: 10.1039/c7tx00244k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 03/20/2018] [Indexed: 12/31/2022] Open
Abstract
Many businesses thrive by producing health supplements from agricultural products, as exemplified by the production of functional (or health) foods using plants traditionally cultivated in rural areas. Dyes, such as indican, indigo, indoxyl, and indirubin, present in dye plants, possess antibacterial, antifungal, and antiproliferative activities. However, these effects may also lead to cytotoxicity. Thus, studies on normal mammalian cells are necessary to identify cytotoxicity and prevent adverse effects of functional foods that contain these dyes. In this study, the effects of indican, indigo, indoxyl, and indirubin were evaluated by flow cytometry using appropriate fluorescent probes in rat thymic lymphocytes. Among the dyes analyzed, indirubin exerted distinct cellular activities. Treatment with indirubin (10-30 μM) increased the population of shrunken dead cells. The side scatter, but not forward scatter, increased in indirubin-treated living cells. It increased the population of annexin V-bound living and dead cells and that of dead cells without annexin V. Indirubin elevated intracellular Ca2+, but not Zn2+ levels. The cellular content of superoxide anions increased and that of glutathione decreased. Indirubin depolarized the cellular plasma and mitochondrial membranes. It did not potentiate or attenuate the cytotoxicity of A23187 (Ca2+ overload) and H2O2 (oxidative stress). The results suggested that indirubin induces both apoptotic and non-apoptotic cell death. It may be difficult to predict and prevent the adverse effects of indirubin due to its diverse activities on normal mammalian cells. Therefore, indirubin should be removed from products that contain dye plant extracts.
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Affiliation(s)
- Yurie Funakoshi
- Faculty of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan . ; Tel: +81-88-656-7256
| | - Ayako Azuma
- Graduate School of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan
| | - Mizuki Ishikawa
- Graduate School of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan
| | - Satoru Itsuki
- Graduate School of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan
| | - Yasuaki Tamura
- Graduate School of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan
| | - Kaori Kanemaru
- Faculty of Bioscience and Bioindustry , Tokushima University , Tokushima 770-8513 , Japan
| | - Shogo Hirai
- Faculty of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan . ; Tel: +81-88-656-7256
- Graduate School of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan
| | - Yasuo Oyama
- Faculty of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan . ; Tel: +81-88-656-7256
- Graduate School of Integrated Arts and Sciences , Tokushima University , Tokushima 770-8502 , Japan
- Faculty of Bioscience and Bioindustry , Tokushima University , Tokushima 770-8513 , Japan
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Nishimura-Danjobara Y, Oyama K, Yokoigawa K, Oyama Y. Hyperpolarization by N-(3-oxododecanoyl)-l-homoserine-lactone, a quorum sensing molecule, in rat thymic lymphocytes. Chem Biol Interact 2018; 283:91-96. [PMID: 29427588 DOI: 10.1016/j.cbi.2018.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 01/22/2018] [Accepted: 02/05/2018] [Indexed: 11/25/2022]
Abstract
To study the adverse effects of N-(3-oxododecanoyl)-l-homoserine-lactone (ODHL), a quorum sensing molecule, on mammalian host cells, its effect on membrane potential was examined in rat thymic lymphocytes using flow cytometric techniques with a voltage-sensitive fluorescent probe. As 3-300 μM ODHL elicited hyperpolarization, it is likely that it increases membrane K+ permeability because hyperpolarization is directly linked to changing K+ gradient across membranes, but not Na+ and Cl- gradients. ODHL did not increase intracellular Ca2+ concentration. ODHL also produced a response in the presence of an intracellular Zn2+ chelator. Thus, it is unlikely that intracellular Ca2+ and Zn2+ are attributed to the response. Quinine, a non-specific K+ channel blocker, greatly reduced hyperpolarization. However, because charybdotoxin, tetraethylammonium chloride, 4-aminopyridine, and glibenclamide did not affect it, it is pharmacologically hypothesized that Ca2+-activated K+ channels, voltage-gated K+ channels, and ATP-sensitive K+ channels are not involved in ODHL-induced hyperpolarization. Although the K+ channels responsible for ODHL-induced hyperpolarization have not been identified, it is suggested that ODHL can elicit hyperpolarization in mammalian host cells, disturbing cellular functions.
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Affiliation(s)
- Yumiko Nishimura-Danjobara
- Department of Food Science, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan
| | - Keisuke Oyama
- Department of Food Science, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan
| | - Kumio Yokoigawa
- Department of Food Science, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan
| | - Yasuo Oyama
- Department of Food Science, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan.
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Takeda M, Oyama K, Kamemura N, Kanemaru K, Yuasa K, Yokoigawa K, Oyama Y. Change in plasma membrane potential of rat thymocytes by tert-butylhydroquinone, a food additive: Possible risk on lymphocytes. Food Chem Toxicol 2017; 109:296-301. [PMID: 28899772 DOI: 10.1016/j.fct.2017.09.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 08/25/2017] [Accepted: 09/08/2017] [Indexed: 12/12/2022]
Abstract
Tertiary butylhydroquinone (TBHQ) is a food additive and has various beneficial actions under in vitro and in vivo experimental conditions. Therefore, it is necessary to collect additional data on the toxicity of TBHQ in order to avoid adverse effects during clinical applications. Changes in plasma membrane potential are associated with changes in physiological functions even in non-excitable cells such as lymphocytes. Thus, compounds that affect membrane potential may modify some lymphocytic functions. The effect of TBHQ on plasma membrane potential was examined in rat thymocytes using flow cytometric techniques. Treatment of rat thymocytes with TBHQ caused hyperpolarization and then depolarization. The TBHQ-induced hyperpolarization was due to the activation of Ca2+-dependent K+ channels. TBHQ elevated intracellular Ca2+ levels. The depolarization by TBHQ was caused by a nonspecific increase in membrane ionic permeability. Both the sustained depolarization and elevation of intracellular Ca2+ level by TBHQ are thought to be adverse for thymocytes because such changes disturb membrane and intracellular signaling. The thymus is most active during neonatal and pre-adolescent periods. If TBHQ exerts adverse actions on thymocytes, it may result in an immunotoxic effect in neonates and adolescents.
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Affiliation(s)
- Maki Takeda
- Faculty of Integrated Arts and Sciences, Tokushima University, Tokushima 770-8502, Japan
| | - Keisuke Oyama
- Osaka University Hospital, Suita, Osaka 565-0871, Japan
| | - Norio Kamemura
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan
| | - Kaori Kanemaru
- Faculty of Integrated Arts and Sciences, Tokushima University, Tokushima 770-8502, Japan; Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan
| | - Keizo Yuasa
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan
| | - Kumio Yokoigawa
- Faculty of Integrated Arts and Sciences, Tokushima University, Tokushima 770-8502, Japan; Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan
| | - Yasuo Oyama
- Faculty of Integrated Arts and Sciences, Tokushima University, Tokushima 770-8502, Japan; Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan.
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Snekalatha S, Kanthakumar P. Ascorbic acid does not modulate potassium currents in cultured human lymphocytes. J Basic Clin Physiol Pharmacol 2017; 28:371-375. [PMID: 28306530 DOI: 10.1515/jbcpp-2016-0182] [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: 12/01/2016] [Accepted: 01/13/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND Ascorbic acid (AA) is known to modulate lymphocyte function, but the mechanism of action is not clearly understood. As voltage-gated potassium currents play an important role in lymphocyte function, the effect of AA on voltage-gated potassium currents was studied. METHODS Peripheral blood mononuclear cells were cultured in the presence of increasing concentrations of AA (0, 0.125, 0.25, 0.5, and 1 mM). Potassium currents in resting lymphocytes were studied by whole cell patch clamp technique using a depolarizing protocol. Lymphocyte function was assessed by measuring interleukin-2 (IL-2) secretion after mitogenic stimulation by ELISA. RESULTS The mean current density of potassium currents recorded from cells cultured for 48 h in the presence of 0.125 mM AA was not significantly different from that of cells cultured in the absence of AA. There was about 50% inhibition of IL-2 secretion in cell cultures with 0.125 mM AA when compared to controls without AA. At higher concentrations of AA, the IL-2 secretion decreased further. CONCLUSIONS The results of the study indicate that the inhibition of lymphocyte function by AA in vitro may not be due to inhibition of potassium currents in the concentration tested.
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Balajthy A, Somodi S, Pethő Z, Péter M, Varga Z, Szabó GP, Paragh G, Vígh L, Panyi G, Hajdu P. 7DHC-induced changes of Kv1.3 operation contributes to modified T cell function in Smith-Lemli-Opitz syndrome. Pflugers Arch 2016; 468:1403-18. [DOI: 10.1007/s00424-016-1851-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 02/06/2023]
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Lovastatin blocks Kv1.3 channel in human T cells: a new mechanism to explain its immunomodulatory properties. Sci Rep 2015; 5:17381. [PMID: 26616555 PMCID: PMC4663632 DOI: 10.1038/srep17381] [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: 07/28/2015] [Accepted: 10/29/2015] [Indexed: 12/13/2022] Open
Abstract
Lovastatin is a member of Statins, which are beneficial in a lot of immunologic cardiovascular diseases and T cell-mediated autoimmune diseases. Kv1.3 channel plays important roles in the activation and proliferation of T cells, and have become attractive target for immune-related disorders. The present study was designed to examine the block effect of Lovastatin on Kv1.3 channel in human T cells, and to clarify its new immunomodulatory mechanism. We found that Lovastatin inhibited Kv1.3 currents in a concentration- and voltage-dependent manner, and the IC50 for peak, end of the pulse was 39.81 ± 5.11, 6.92 ± 0.95 μM, respectively. Lovastatin also accelerated the decay rate of current inactivation and negatively shifted the steady-state inactivation curves concentration-dependently, without affecting the activation curve. However, 30 μM Lovastatin had no apparent effect on KCa current in human T cells. Furthermore, Lovastatin inhibited Ca2+ influx, T cell proliferation as well as IL-2 production. The activities of NFAT1 and NF-κB p65/50 were down-regulated by Lovastatin, too. At last, Mevalonate application only partially reversed the inhibition of Lovastatin on IL-2 secretion, and the siRNA against Kv1.3 also partially reduced this inhibitory effect of Lovastatin. In conclusion, Lovastatin can exert immunodulatory properties through the new mechanism of blocking Kv1.3 channel.
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Kazama I, Tamada T, Tachi M. Usefulness of targeting lymphocyte Kv1.3-channels in the treatment of respiratory diseases. Inflamm Res 2015. [PMID: 26206235 DOI: 10.1007/s00011-015-0855-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
T lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes. Patch-clamp studies revealed that the channels play crucial roles in facilitating the calcium influx necessary to trigger lymphocyte activation and proliferation. Using selective channel inhibitors in experimental animal models, in vivo studies further revealed the clinically relevant relationship between the channel expression and the development of chronic respiratory diseases, in which chronic inflammation or the overstimulation of cellular immunity in the airways is responsible for the pathogenesis. In chronic respiratory diseases, such as chronic obstructive pulmonary disease, asthma, diffuse panbronchiolitis and cystic fibrosis, in addition to the supportive management for the symptoms, the anti-inflammatory effects of macrolide antibiotics were shown to be effective against the over-activation or proliferation of T lymphocytes. Recently, we provided physiological and pharmacological evidence that macrolide antibiotics, together with calcium channel blockers, HMG-CoA reductase inhibitors, and nonsteroidal anti-inflammatory drugs, effectively suppress the Kv1.3-channel currents in lymphocytes, and thus exert anti-inflammatory or immunomodulatory effects. In this review article, based on the findings obtained from recent in vivo and in vitro studies, we address the novel therapeutic implications of targeting the lymphocyte Kv1.3-channels for the treatment of chronic or acute respiratory diseases.
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Affiliation(s)
- Itsuro Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan.
| | - Tsutomu Tamada
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Masahiro Tachi
- Department of Plastic and Reconstructive Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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17
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Roles of lymphocyte Kv1.3-channels in gut mucosal immune system: Novel therapeutic implications for inflammatory bowel disease. Med Hypotheses 2015; 85:61-3. [DOI: 10.1016/j.mehy.2015.03.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/25/2015] [Indexed: 01/16/2023]
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Kazama I. Physiological significance of delayed rectifier K(+) channels (Kv1.3) expressed in T lymphocytes and their pathological significance in chronic kidney disease. J Physiol Sci 2015; 65:25-35. [PMID: 25096892 PMCID: PMC10717717 DOI: 10.1007/s12576-014-0331-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/14/2014] [Indexed: 11/24/2022]
Abstract
T lymphocytes predominantly express delayed rectifier K(+) channels (Kv1.3) in their plasma membranes. More than 30 years ago, patch-clamp studies revealed that the channels play crucial roles in facilitating the calcium influx necessary to trigger lymphocyte activation and proliferation. In addition to selective channel inhibitors that have been developed, we recently showed physiological evidence that drugs such as nonsteroidal anti-inflammatory drugs, antibiotics, and anti-hypertensives effectively suppress the channel currents in lymphocytes, and thus exert immunosuppressive effects. Using experimental animal models, previous studies revealed the pathological relevance between the expression of ion channels and the progression of renal diseases. As an extension, we recently demonstrated that the overexpression of lymphocyte Kv1.3 channels contributed to the progression of chronic kidney disease (CKD) by promoting cellular proliferation and interstitial fibrosis. Together with our in-vitro results, the studies indicated the therapeutic potency of Kv1.3-channel inhibitors in the treatment or the prevention of CKD.
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Affiliation(s)
- Itsuro Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan,
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Subramanyam P, Colecraft HM. Ion channel engineering: perspectives and strategies. J Mol Biol 2014; 427:190-204. [PMID: 25205552 DOI: 10.1016/j.jmb.2014.09.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/01/2014] [Indexed: 01/19/2023]
Abstract
Ion channels facilitate the passive movement of ions down an electrochemical gradient and across lipid bilayers in cells. This phenomenon is essential for life and underlies many critical homeostatic processes in cells. Ion channels are diverse and differ with respect to how they open and close (gating) and to their ionic conductance/selectivity (permeation). Fundamental understanding of ion channel structure-function mechanisms, their physiological roles, how their dysfunction leads to disease, their utility as biosensors, and development of novel molecules to modulate their activity are important and active research frontiers. In this review, we focus on ion channel engineering approaches that have been applied to investigate these aspects of ion channel function, with a major emphasis on voltage-gated ion channels.
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Affiliation(s)
- Prakash Subramanyam
- Department of Physiology and Cellular Biophysics, Columbia University, NY, 10032, USA
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, NY, 10032, USA.
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20
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Yang M, Brackenbury WJ. Membrane potential and cancer progression. Front Physiol 2013; 4:185. [PMID: 23882223 PMCID: PMC3713347 DOI: 10.3389/fphys.2013.00185] [Citation(s) in RCA: 362] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 06/28/2013] [Indexed: 12/27/2022] Open
Abstract
Membrane potential (Vm), the voltage across the plasma membrane, arises because of the presence of different ion channels/transporters with specific ion selectivity and permeability. Vm is a key biophysical signal in non-excitable cells, modulating important cellular activities, such as proliferation and differentiation. Therefore, the multiplicities of various ion channels/transporters expressed on different cells are finely tuned in order to regulate the Vm. It is well-established that cancer cells possess distinct bioelectrical properties. Notably, electrophysiological analyses in many cancer cell types have revealed a depolarized Vm that favors cell proliferation. Ion channels/transporters control cell volume and migration, and emerging data also suggest that the level of Vm has functional roles in cancer cell migration. In addition, hyperpolarization is necessary for stem cell differentiation. For example, both osteogenesis and adipogenesis are hindered in human mesenchymal stem cells (hMSCs) under depolarizing conditions. Therefore, in the context of cancer, membrane depolarization might be important for the emergence and maintenance of cancer stem cells (CSCs), giving rise to sustained tumor growth. This review aims to provide a broad understanding of the Vm as a bioelectrical signal in cancer cells by examining several key types of ion channels that contribute to its regulation. The mechanisms by which Vm regulates cancer cell proliferation, migration, and differentiation will be discussed. In the long term, Vm might be a valuable clinical marker for tumor detection with prognostic value, and could even be artificially modified in order to inhibit tumor growth and metastasis.
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Affiliation(s)
- Ming Yang
- Department of Biology, University of York York, UK
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Kazama I, Maruyama Y. Differential effects of clarithromycin and azithromycin on delayed rectifier K(+)-channel currents in murine thymocytes. PHARMACEUTICAL BIOLOGY 2013; 51:760-765. [PMID: 23527897 DOI: 10.3109/13880209.2013.764539] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
CONTEXT Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and the channels play crucial roles in the lymphocyte activation and proliferation. Since macrolide antibiotics, such as clarithromycin and azithromycin, exert immunomodulatory effects, they would affect the Kv1.3-channel currents in lymphocytes. OBJECTIVE This study determined the physiological involvement in the mechanisms of immunomodulation by these antibiotics. MATERIALS AND METHODS Employing the standard patch-clamp whole-cell recording technique in murine thymocytes, we examined the effects of 30 and 100 µM clarithromycin and azithromycin on the Kv1.3-channel currents and the membrane capacitance. RESULTS Clarithromycin significantly suppressed the peak currents (30 µM, 178 ± 5.6 to 111 ± 2.0 pA/pF; 100 µM, 277 ± 4.4 to 89.6 ± 10 pA/pF) and the pulse-end currents (30 µM, 47.5 ± 2.2% to 15.5 ± 3.3%; 100 µM, 48.5 ± 1.4% to 15.8 ± 1.0%) of thymocyte Kv1.3-channels without significant effects on the membrane capacitance. In contrast, azithromycin did not affect the channel currents. However, it significantly decreased the membrane capacitance (30 µM, 4.68 ± 0.14 to 3.74 ± 0.13 pF; 100 µM, 4.47 ± 0.06 to 3.37 ± 0.08 pF), indicating its accumulation in the plasma membrane. DISCUSSION AND CONCLUSION This study demonstrated for the first time that clarithromycin exerts inhibitory effects on thymocyte Kv1.3-channel currents, while azithromycin decreases the membrane capacitance without affecting the channel currents. These differences in the effects of the macrolide antibiotics may reflect differences in the mechanisms of immunomodulation by which they control the production of cytokines.
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Affiliation(s)
- Itsuro Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Miyagi, Japan.
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Hu L, Wang T, Gocke AR, Nath A, Zhang H, Margolick JB, Whartenby KA, Calabresi PA. Blockade of Kv1.3 potassium channels inhibits differentiation and granzyme B secretion of human CD8+ T effector memory lymphocytes. PLoS One 2013; 8:e54267. [PMID: 23382885 PMCID: PMC3559683 DOI: 10.1371/journal.pone.0054267] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 12/10/2012] [Indexed: 01/10/2023] Open
Abstract
Increased expression of the voltage-gated potassium channel Kν1.3 on activated effector memory T cells (T(EM)) is associated with pathology in multiple sclerosis (MS). To date, most studies of Kν1.3 channels in MS have focused on CD4+ T(EM) cells. Much less is known about the functional relevance of Kv1.3 on CD8+ T(EM) cells. Herein, we examined the effects of Kν1.3 blockade on CD8+ T cell proliferation, differentiation into cytotoxic effector cells, and release of granzyme B (GrB), a key effector of CD8+ T cell-mediated cytotoxicity. We confirmed the expression of Kv1.3 channels on activated human CD8+ T lymphocytes by immunofluorescent staining. To test the functional relevance of the Kv1.3 channel in CD8+ T cells, we inhibited this channel via pharmacological blockers or a lentiviral-dominant negative (Kv1.xDN) approach and determined the effects of the blockade on critical pathogenic parameters of CD8+ T cells. We found that blockade of Kv1.3 with both lentivirus and pharmacologic agents effectively inhibited cytotoxic effector memory cells' proliferation, secretion of GrB, and their ability to kill neural progenitor cells. Intriguingly, the KvDN transduced T cells exhibited arrested differentiation from central memory (T(CM)) to effector memory (T(EM)) states. Transduction of cells that had already differentiated into T(EM) with KvDN led to their conversion into T(CM). CD8+ T(EM) have a critical role in MS and other autoimmune diseases. Our present results indicate a critical role for Kv1.3 in the conversion of CD8+ T cells into potential pathogenic effector cells with cytotoxic function.
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Affiliation(s)
- Lina Hu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Tongguang Wang
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anne R. Gocke
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hao Zhang
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Joseph B. Margolick
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Katharine A. Whartenby
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Peter A. Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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Yang Y, Wang YF, Yang XF, Wang ZH, Lian YT, Yang Y, Li XW, Gao X, Chen J, Shu YW, Cheng LX, Liao YH, Liu K. Specific Kv1.3 blockade modulates key cholesterol-metabolism-associated molecules in human macrophages exposed to ox-LDL. J Lipid Res 2012; 54:34-43. [PMID: 23099443 DOI: 10.1194/jlr.m023846] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cholesterol-metabolism-associated molecules, including scavenger receptor class A (SR-A), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), CD36, ACAT1, ABCA1, ABCG1, and scavenger receptor class B type I, can modulate cholesterol metabolism in the transformation from macrophages to foam cells. Voltage-gated potassium channel Kv1.3 has increasingly been demonstrated to play an important role in the modulation of macrophage function. Here, we investigate the role of Kv1.3 in modulating cholesterol-metabolism-associated molecules in human acute monocytic leukemia cell-derived macrophages (THP-1 macrophages) and human monocyte-derived macrophages exposed to oxidized LDL (ox-LDL). Human Kv1.3 and Kv1.5 channels (hKv1.3 and hKv1.5) are expressed in macrophages and form a heteromultimeric channel. The hKv1.3-E314 antibody that we had generated as a specific hKv1.3 blocker inhibited outward delayed rectifier potassium currents, whereas the hKv1.5-E313 antibody that we had generated as a specific hKv1.5 blocker failed. Accordingly, the hKv1.3-E314 antibody reduced percentage of cholesterol ester and enhanced apoA-I-mediated cholesterol efflux in THP-1 macrophages and human monocyte-derived macrophages exposed to ox-LDL. The hKv1.3-E314 antibody downregulated SR-A, LOX-1, and ACAT1 expression and upregulated ABCA1 expression in THP-1 macrophages and human monocyte-derived macrophages. Our results reveal that specific Kv1.3 blockade represents a novel strategy modulating cholesterol metabolism in macrophages, which benefits the treatment of atherosclerotic lesions.
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Affiliation(s)
- Yong Yang
- Department of Cardiology, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
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Kazama I, Maruyama Y, Matsubara M. Benidipine persistently inhibits delayed rectifier K(+)-channel currents in murine thymocytes. Immunopharmacol Immunotoxicol 2012; 35:28-33. [PMID: 22978806 DOI: 10.3109/08923973.2012.723011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and the channels play crucial roles in the lymphocyte activation and proliferation. Since 1,4-dihydropyridine (DHP) Ca(2+) channel blockers (CCBs), which are highly lipophilic, exert relatively stronger immunomodulatory effects than the other types of CCBs, they would affect the Kv1.3-channel currents in lymphocytes. In the present study, employing the standard patch-clamp whole-cell recording technique in murine thymocytes, we examined the effects of benidipine, one of the most lipophilic DHPs, on the channel currents and the membrane capacitance and compared them with those of nifedipine. Both drugs significantly suppressed the peak and the pulse-end currents of the channels with significant decreases in the membrane capacitance. However, the effects of benidipine were more marked than those of nifedipine and were irreversible after the drug withdrawal. This study demonstrated for the first time that DHP CCBs, such as nifedipine and benidipine, exert inhibitory effects on thymocyte Kv1.3-channel currents. The persistent effect of benidipine was thought to be associated with its sustained accumulation in the plasma membranes as detected by the long-lasting decrease in the membrane capacitance.
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Affiliation(s)
- Itsuro Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan.
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Macedo-Junior SJ, Nascimento FP, Luiz-Cerutti M, Santos ARS. Role of pertussis toxin-sensitive G-protein, K+ channels, and voltage-gated Ca2+ channels in the antinociceptive effect of inosine. Purinergic Signal 2012; 9:51-8. [PMID: 22806273 DOI: 10.1007/s11302-012-9327-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 06/26/2012] [Indexed: 12/20/2022] Open
Abstract
Inosine is the first metabolite of adenosine. It exerts an antinociceptive effect by activating the adenosine A(1) and A(2A) receptors. We have previously demonstrated that inosine exhibits antinociceptive properties in acute and chronic mice models of nociception. The aim of this study was to investigate the involvement of pertussis toxin-sensitive G-protein-coupled receptors, as well as K(+) and Ca(2+) channels, in the antinociception promoted by inosine in the formalin test. Mice were pretreated with pertussis toxin (2.5 μg/site, i.t., an inactivator of G(i/0) protein); after 7 days, they received inosine (10 mg/kg, i.p.) or morphine (2.5 mg/kg, s.c., used as positive control) immediately before the formalin test. Another group of animals received tetraethylammonium (TEA) or 4-aminopyridine (4-AP) (1 μg/site, i.t., a non-specific voltage-gated K(+) channel blockers), apamin (50 ng/site, i.t., a small conductance Ca(2+)-activated K(+) channel blocker), charybdotoxin (250 pg/site, i.t., a large-conductance Ca(2+)-activated K(+) channel blocker), glibenclamide (100 μg/site, i.t., an ATP-sensitive K(+) channel blocker) or CaCl(2) (200 nmol/site, i.t.). Afterwards, the mice received inosine (10 mg/kg, i.p.), diclofenac (10 mg/kg, i.p., a positive control), or morphine (2.5 mg/kg, s.c., a positive control) immediately before the formalin test. The antinociceptive effect of inosine was reversed by the pre-administration of pertussis toxin (2.5 μg/site, i.t.), TEA, 4-aminopyridine, charybdotoxin, glibenclamide, and CaCl(2), but not apamin. Further, all K(+) channel blockers and CaCl(2) reversed the antinociception induced by diclofenac and morphine, respectively. Taken together, these data suggest that the antinociceptive effect of inosine is mediated, in part, by pertussis toxin-sensitive G-protein coupled receptors and the subsequent activation of voltage gated K(+) channel, large conductance Ca(2+)-activated and ATP-sensitive K(+) channels or inactivation of voltage-gated Ca(2+) channels. Finally, small conductance Ca(2+)-activated K(+) channels are not involved in the antinociceptive effect of inosine.
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Affiliation(s)
- Sérgio José Macedo-Junior
- Laboratório de Neurobiologia da Dor e Inflamação, Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Trindade, Florianópolis, SC, 88040-900, Brazil
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Chang SC, Galea CA, Leung EWW, Tajhya RB, Beeton C, Pennington MW, Norton RS. Expression and isotopic labelling of the potassium channel blocker ShK toxin as a thioredoxin fusion protein in bacteria. Toxicon 2012; 60:840-50. [PMID: 22659540 DOI: 10.1016/j.toxicon.2012.05.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/21/2012] [Accepted: 05/23/2012] [Indexed: 01/02/2023]
Abstract
The polypeptide toxin ShK is a potent blocker of Kv1.3 potassium channels, which play a crucial role in the activation of human effector memory T-cells (T(EM)). Selective blockers constitute valuable therapeutic leads for the treatment of autoimmune diseases mediated by T(EM) cells, such as multiple sclerosis, rheumatoid arthritis, and type-1 diabetes. We have established a recombinant peptide expression system in order to generate isotopically-labelled ShK and various ShK analogues for in-depth biophysical and pharmacological studies. ShK was expressed as a thioredoxin fusion protein in Escherichia coli BL21 (DE3) cells and purified initially by Ni²⁺ iminodiacetic acid affinity chromatography. The fusion protein was cleaved with enterokinase and purified to homogeneity by reverse-phase HPLC. NMR spectra of ¹⁵N-labelled ShK were similar to those reported previously for the unlabelled synthetic peptide, confirming that recombinant ShK was correctly folded. Recombinant ShK blocked Kv1.3 channels with a K(d) of 25 pM and inhibited the proliferation of human and rat T lymphocytes with a preference for T(EM) cells, with similar potency to synthetic ShK in all assays. This expression system also enables the efficient production of ¹⁵N-labelled ShK for NMR studies of peptide dynamics and of the interaction of ShK with Kv1.3 channels.
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Affiliation(s)
- Shih Chieh Chang
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
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Kazama I, Maruyama Y, Murata Y, Sano M. Voltage-dependent biphasic effects of chloroquine on delayed rectifier K(+)-channel currents in murine thymocytes. J Physiol Sci 2012; 62:267-74. [PMID: 22328488 PMCID: PMC10716932 DOI: 10.1007/s12576-012-0195-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 01/20/2012] [Indexed: 11/29/2022]
Abstract
Lymphocytes are of rich in delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and the channels play crucial roles in the lymphocyte activation and proliferation. Since chloroquine, a widely used anti-malarial drug, exerts immunosuppressive effects, it will affect the channel currents in lymphocytes. In the present study, employing the standard patch-clamp whole-cell recording technique, we examined the effects of chloroquine on the channels expressed in murine thymocytes. Published papers report that chloroquine will inhibit voltage-dependent K(+)-channel currents by plugging into the open-pore. We observed, indeed, that chloroquine suppressed the pulse-end currents of Kv1.3-channels at higher voltage steps. Surprisingly, however, we found that the drug enhanced the peak currents at both higher and lower voltage steps. Since chloroquine showed such biphasic effects on the thymocyte K(+)-channels, and since those effects were voltage dependent, we examined the effects of chloroquine on the activation and the inactivation of the channel currents. We noted that chloroquine shifted both the activation and the inactivation curves toward the hyperpolarizing potential, and that those shifts were more emphasized at lower voltage steps. We conclude that chloroquine facilitates both the activation and the inactivation of Kv1.3-channel currents in thymocytes, and that those effects are voltage dependent.
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Affiliation(s)
- I Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan.
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Kazama I, Maruyama Y, Murata Y. Suppressive effects of nonsteroidal anti-inflammatory drugs diclofenac sodium, salicylate and indomethacin on delayed rectifier K+-channel currents in murine thymocytes. Immunopharmacol Immunotoxicol 2012; 34:874-8. [PMID: 22409730 DOI: 10.3109/08923973.2012.666249] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and the channels play crucial roles in the lymphocyte activation and proliferation. Since nonsteroidal anti-inflammatory drugs (NSAIDs), the most commonly used analgesic and antipyretic drugs, exert immunomodulatory effects, they would affect the channel currents in lymphocytes. In the present study, employing the standard patch-clamp whole-cell recording technique, we examined the effects of diclofenac sodium, salicylate and indomethacin on the channel currents in murine thymocytes and the membrane capacitance. Diclofenac sodium and salicylate significantly suppressed the pulse-end currents of the channel. However, indomethacin suppressed both the peak and the pulse-end currents with a significant increase in the membrane capacitance. This study demonstrated for the first time that NSAIDs, such as diclofenac sodium, salicylate and indomethacin, exert inhibitory effects on thymocyte Kv1.3-channel currents. The slow inactivation pattern induced by indomethacin was thought to be associated with microscopic changes in the plasma membrane surface detected by the increase in the membrane capacitance.
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Affiliation(s)
- Itsuro Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Seiryo-cho, Aoba-ku, Sendai, Miyagi, Japan.
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Lam J, Wulff H. The Lymphocyte Potassium Channels Kv1.3 and KCa3.1 as Targets for Immunosuppression. Drug Dev Res 2011; 72:573-584. [PMID: 22241939 PMCID: PMC3253536 DOI: 10.1002/ddr.20467] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The voltage-gated Kv1.3 and the calcium-activated KCa3.1 potassium channel modulate many calcium-dependent cellular processes in immune cells, including T-cell activation and proliferation, and have therefore been proposed as novel therapeutic targets for immunomodulation. Kv1.3 is highly expressed in CCR7(-) effector memory T cells and is emerging as a target for T-cell mediated diseases like multiple sclerosis, rheumatoid arthritis, type-1 diabetes mellitus, allergic contact dermatitis, and psoriasis. KCa3.1 in contrast is expressed in CCR7(+) naïve and central memory T cells, as well as in mast cells, macrophages, dedifferentiated vascular smooth muscle cells, fibroblasts, vascular endothelium, and airway epithelium. Given this expression pattern, KCa3.1 is a potential therapeutic target for conditions ranging from inflammatory bowel disease, multiple sclerosis, arthritis, and asthma to cardiovascular diseases like atherosclerosis and post-angioplasty restenosis. Results from animal studies have been supportive of the therapeutic potential of both Kv1.3 and KCa3.1 blockers and have also not shown any toxicities associated with pharmacological Kv1.3 and KCa3.1 blockade. To date, two compounds targeting Kv1.3 are in preclinical development but, so far, no Kv1.3 blocker has advanced into clinical trials. KCa3.1 blockers, on the other hand, have been evaluated in clinical trials for sickle cell anemia and exercise-induced asthma, but have so far not shown efficacy. However, the trial results support KCa3.1 as a safe therapeutic target, and will hopefully help enable clinical trials for other medical conditions that might benefit from KCa3.1 blockade.
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Affiliation(s)
- Jenny Lam
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
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30
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Villalonga N, David M, Bielańska J, González T, Parra D, Soler C, Comes N, Valenzuela C, Felipe A. Immunomodulatory effects of diclofenac in leukocytes through the targeting of Kv1.3 voltage-dependent potassium channels. Biochem Pharmacol 2010; 80:858-66. [DOI: 10.1016/j.bcp.2010.05.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 05/10/2010] [Accepted: 05/11/2010] [Indexed: 10/19/2022]
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31
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Rangaraju S, Chi V, Pennington MW, Chandy KG. Kv1.3 potassium channels as a therapeutic target in multiple sclerosis. Expert Opin Ther Targets 2010; 13:909-24. [PMID: 19538097 DOI: 10.1517/14728220903018957] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We discuss the potential use of inhibitors of Kv1.3 potassium channels in T lymphocytes as therapeutics for multiple sclerosis. Current treatment strategies target the immune system in a non-selective manner. The resulting general immunosuppression, toxic side-effects and increased risk of opportunistic infections create the need for more selective therapeutics. Autoreactive effector-memory T (T(EM)) cells, considered to be major mediators of autoimmunity, express large numbers of Kv1.3 channels. Selective blockers of Kv1.3 inhibit calcium signaling, cytokine production and proliferation of T(EM) cells in vitro, and T(EM) cell-motility in vivo. Kv1.3 blockers ameliorate disease in animal models of multiple sclerosis, rheumatoid arthritis, type 1 diabetes mellitus and contact dermatitis without compromising the protective immune response to acute infections. Kv1.3 blockers have a good safety profile in rodents and primates.
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Affiliation(s)
- Srikant Rangaraju
- University of California, Department of Physiology and Biophysics, Irvine, California 92697, USA
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32
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Grgic I, Wulff H, Eichler I, Flothmann C, Köhler R, Hoyer J. Blockade of T-lymphocyte KCa3.1 and Kv1.3 channels as novel immunosuppression strategy to prevent kidney allograft rejection. Transplant Proc 2010; 41:2601-6. [PMID: 19715983 DOI: 10.1016/j.transproceed.2009.06.025] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Currently, there is an unmet clinical need for novel immunosuppressive agents for long-term prevention of kidney transplant rejection as alternatives to the nephrotoxic calcineurin inhibitor cyclosporine (CsA). Recent studies have shown that K(+) channels have a crucial role in T-lymphocyte activity. We investigated whether combined blockade of the T-cell K(+) channels K(Ca)3.1 and K(v)1.3, both of which regulate calcium signaling during lymphocyte activation, is effective in prevention of rejection of kidney allografts from Fisher rats to Lewis rats. All recipients were initially treated with CsA (5 mg/kg d) for 7 days. In rats with intact allograft function, treatment was continued for 10 days with either CsA (5 mg/kg d), or a combination of TRAM-34 (K(Ca)3.1 inhibitor; 120 mg/kg d) plus Stichodactyla helianthus toxin (ShK, K(v)1.3 inhibitor; 80 microg/kg 3 times daily), or vehicle alone. Kidney sections were stained with periodic acid-Schiff or hematoxylin-eosin and histochemically for markers of macrophages (CD68), T-lymphocytes (CD43), or cytotoxic T-cells (CD8). Our results showed that treatment with TRAM-34 and ShK reduced total interstitial mononuclear cell infiltration (-42%) and the number of CD43+ T-cells (-32%), cytotoxic CD8+ T-cells (-32%), and CD68+ macrophages (-26%) in allografts when compared to vehicle treatment alone. Efficacy of TRAM-34/ShK treatment was comparable with that of CsA. In addition, no visible organ damage or other discernible adverse effects were observed with this treatment. Thus, selective blockade of T-lymphocyte K(Ca)3.1 and K(v)1.3 channels may represent a novel alternative therapy for prevention of kidney allograft rejection.
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Affiliation(s)
- I Grgic
- Department of Internal Medicine and Nephrology, University Hospital, Philipps-University, Marburg, Germany
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33
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Takacs Z, Toups M, Kollewe A, Johnson E, Cuello LG, Driessens G, Biancalana M, Koide A, Ponte CG, Perozo E, Gajewski TF, Suarez-Kurtz G, Koide S, Goldstein SAN. A designer ligand specific for Kv1.3 channels from a scorpion neurotoxin-based library. Proc Natl Acad Sci U S A 2009; 106:22211-6. [PMID: 20007782 PMCID: PMC2799710 DOI: 10.1073/pnas.0910123106] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Indexed: 02/03/2023] Open
Abstract
Venomous animals immobilize prey using protein toxins that act on ion channels and other targets of biological importance. Broad use of toxins for biomedical research, diagnosis, and therapy has been limited by inadequate target discrimination, for example, among ion channel subtypes. Here, a synthetic toxin is produced by a new strategy to be specific for human Kv1.3 channels, critical regulators of immune T cells. A phage display library of 11,200 de novo proteins is designed using the alpha-KTx scaffold of 31 scorpion toxin sequences known or predicted to bind to potassium channels. Mokatoxin-1 (moka1) is isolated by affinity selection on purified target. Moka1 blocks Kv1.3 at nanomolar levels that do not inhibit Kv1.1, Kv1.2, or KCa1.1. As a result, moka1 suppresses CD3/28-induced cytokine secretion by T cells without cross-reactive gastrointestinal hyperactivity. The 3D structure of moka1 rationalizes its specificity and validates the engineering approach, revealing a unique interaction surface supported on an alpha-KTx scaffold. This scaffold-based/target-biased strategy overcomes many obstacles to production of selective toxins.
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Affiliation(s)
- Zoltan Takacs
- Department of Pediatrics and Institute of Molecular Pediatric Sciences
| | - Megan Toups
- Department of Pediatrics and Institute of Molecular Pediatric Sciences
| | - Astrid Kollewe
- Department of Pediatrics and Institute of Molecular Pediatric Sciences
| | - Erik Johnson
- Department of Pediatrics and Institute of Molecular Pediatric Sciences
| | | | - Gregory Driessens
- Departments of Pathology and Medicine, Pritzker School of Medicine, University of Chicago, Chicago, IL 60637
| | | | - Akiko Koide
- Department of Biochemistry and Molecular Biology, and
| | - Cristiano G. Ponte
- Coordenação de Biotecnologia, Instituto Federal do Rio de Janeiro, Rio de Janeiro, 20270-021, Brazil; and
| | | | - Thomas F. Gajewski
- Departments of Pathology and Medicine, Pritzker School of Medicine, University of Chicago, Chicago, IL 60637
| | - Guilherme Suarez-Kurtz
- Divisão de Farmacologia, Instituto Nacional de Câncer, Rio de Janeiro, 20231-050, Brazil
| | - Shohei Koide
- Department of Biochemistry and Molecular Biology, and
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Blackiston DJ, McLaughlin KA, Levin M. Bioelectric controls of cell proliferation: ion channels, membrane voltage and the cell cycle. Cell Cycle 2009; 8:3527-36. [PMID: 19823012 DOI: 10.4161/cc.8.21.9888] [Citation(s) in RCA: 295] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
All cells possess long-term, steady-state voltage gradients across the plasma membrane. These transmembrane potentials arise from the combined activity of numerous ion channels, pumps and gap junction complexes. Increasing data from molecular physiology now reveal that the role of changes in membrane voltage controls, and is in turn controlled by, progression through the cell cycle. We review recent functional data on the regulation of mitosis by bioelectric signals, and the function of membrane voltage and specific potassium, sodium and chloride ion channels in the proliferation of embryonic, somatic and neoplastic cells. Its unique properties place this powerful, well-conserved, but still poorly-understood signaling system at the center of the coordinated cellular interactions required for complex pattern formation. Moreover, disregulation of ion channel expression and function is increasingly observed to be not only a useful marker but likely a functional element in oncogenesis. New advances in genomics and the development of in vivo biophysical techniques suggest exciting opportunities for molecular medicine, bioengineering and regenerative approaches to human health.
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Affiliation(s)
- Douglas J Blackiston
- Biology Department, and Center for Regenerative and Developmental Biology, Tufts University, Medford, MA, USA
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35
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Zsiros E, Kis-Toth K, Hajdu P, Gaspar R, Bielanska J, Felipe A, Rajnavolgyi E, Panyi G. Developmental switch of the expression of ion channels in human dendritic cells. THE JOURNAL OF IMMUNOLOGY 2009; 183:4483-92. [PMID: 19748986 DOI: 10.4049/jimmunol.0803003] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Modulation of the expression and activity of plasma membrane ion channels is one of the mechanisms by which immune cells can regulate their intracellular Ca(2+) signaling pathways required for proliferation and/or differentiation. Voltage-gated K+ channels, inwardly rectifying K+ channels, and Ca(2+)-activated K+ channels have been described to play a major role in controlling the membrane potential in lymphocytes and professional APCs, such as monocytes, macrophages, and dendritic cells (DCs). Our study aimed at the characterization and identification of ion channels expressed in the course of human DC differentiation from monocytes. We report in this study for the first time that immature monocyte-derived DCs express voltage-gated Na+ channels in their plasma membrane. The analysis of the biophysical and pharmacological properties of the current and PCR-based cloning revealed the presence of Nav1.7 channels in immature DCs. Transition from the immature to a mature differentiation state, however, was accompanied by the down-regulation of Nav1.7 expression concomitant with the up-regulation of voltage-gated Kv1.3 K+ channel expression. The presence of Kv1.3 channels seems to be common for immune cells; hence, selective Kv1.3 blockers may emerge as candidates for inhibiting various functions of mature DCs that involve their migratory, cytokine-secreting, and T cell-activating potential.
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Affiliation(s)
- Emese Zsiros
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen 4012, Hungary
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36
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Abstract
For more than 25 years, it has been widely appreciated that Ca2+ influx is essential to trigger T-lymphocyte activation. Patch clamp analysis, molecular identification, and functional studies using blockers and genetic manipulation have shown that a unique contingent of ion channels orchestrates the initiation, intensity, and duration of the Ca2+ signal. Five distinct types of ion channels--Kv1.3, KCa3.1, Orai1+ stromal interacting molecule 1 (STIM1) [Ca2+-release activating Ca2+ (CRAC) channel], TRPM7, and Cl(swell)--comprise a network that performs functions vital for ongoing cellular homeostasis and for T-cell activation, offering potential targets for immunomodulation. Most recently, the roles of STIM1 and Orai1 have been revealed in triggering and forming the CRAC channel following T-cell receptor engagement. Kv1.3, KCa3.1, STIM1, and Orai1 have been found to cluster at the immunological synapse following contact with an antigen-presenting cell; we discuss how channels at the synapse might function to modulate local signaling. Immuno-imaging approaches are beginning to shed light on ion channel function in vivo. Importantly, the expression pattern of Ca2+ and K+ channels and hence the functional network can adapt depending upon the state of differentiation and activation, and this allows for different stages of an immune response to be targeted specifically.
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Affiliation(s)
- Michael D Cahalan
- Department of Physiology and Biophysics, and the Institute for Immunology, University of California, Irvine, Irvine, CA 92697-4561, USA.
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37
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Sundelacruz S, Levin M, Kaplan DL. Role of membrane potential in the regulation of cell proliferation and differentiation. Stem Cell Rev Rep 2009; 5:231-46. [PMID: 19562527 PMCID: PMC10467564 DOI: 10.1007/s12015-009-9080-2] [Citation(s) in RCA: 325] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 06/07/2009] [Indexed: 12/11/2022]
Abstract
Biophysical signaling, an integral regulator of long-term cell behavior in both excitable and non-excitable cell types, offers enormous potential for modulation of important cell functions. Of particular interest to current regenerative medicine efforts, we review several examples that support the functional role of transmembrane potential (V(mem)) in the regulation of proliferation and differentiation. Interestingly, distinct V(mem) controls are found in many cancer cell and precursor cell systems, which are known for their proliferative and differentiation capacities, respectively. Collectively, the data demonstrate that bioelectric properties can serve as markers for cell characterization and can control cell mitotic activity, cell cycle progression, and differentiation. The ability to control cell functions by modulating bioelectric properties such as V(mem) would be an invaluable tool for directing stem cell behavior toward therapeutic goals. Biophysical properties of stem cells have only recently begun to be studied and are thus in need of further characterization. Understanding the molecular and mechanistic basis of biophysical regulation will point the way toward novel ways to rationally direct cell functions, allowing us to capitalize upon the potential of biophysical signaling for regenerative medicine and tissue engineering.
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Affiliation(s)
- Sarah Sundelacruz
- Department of Biomedical Engineering, Tufts University, 4 Colby St., Medford, MA 02155, USA
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38
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Cong B, Han G, Huang XH, Liu SH, Liu CL, Lin XZ, He PQ, Gasaino H. Molecular cloning and tissue expression patterns of a small conductance calcium-activated potassium channel gene in turbot (Scophthalmus maximus L.). FISH & SHELLFISH IMMUNOLOGY 2009; 27:221-229. [PMID: 19481607 DOI: 10.1016/j.fsi.2009.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 05/05/2009] [Accepted: 05/06/2009] [Indexed: 05/27/2023]
Abstract
Calcium-activated potassium channels on plasma membrane enable potassium influx into the cell with ensuing changes in plasma membrane potential and consequent effects on cellular metabolic functions. Recently, this potassium channel was reported to regulate the cellular responses of mammalian immune cells. We have postulated the presence of such a channel in fish immune cells and its potential role in immunoregulation in fish. Employing specific primers and RNA template, we cloned a segment of a novel gene from turbot blood sample and subsequently obtained a full cDNA sequence using RACE approaches. Bioinformatic analysis revealed structural and phylogenetic characteristics of a novel small conductance calcium-activated potassium channel gene, we called TSKCa, which exhibits homologous domains to other species particularly in the transmembrane regions. Full-length TSKCa cDNA is 1698 bp with a 1632 bp open reading frame encoding a protein of 544 amino acids. TSKCa gene is expressed in majority of the tested organs and tissues of turbot. To assess the postulated immune function of TSKCa, we infected turbot with the pathogen Vibrio anguillarum. Here, semi-quantitative RT-PCR analysis demonstrated increased mRNA expression of TSKCa in head kidney, spleen and blood, indicating an important role of TSKCa in these organ tissues that mediate the immune defense response of turbot. In contrast, there was less change in expression in the turbot intestines and liver which were less implicated in the immune response in present study.
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Affiliation(s)
- Bailin Cong
- The Key Laboratory of Marine Bioactive Substance, SOA, Qingdao 266061, PR China
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Comment on “Functional consequences of Kv1.3 ion channel rearrangement into the immunological synapse”. Immunol Lett 2009; 125:156-7. [DOI: 10.1016/j.imlet.2009.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2009] [Revised: 06/26/2009] [Accepted: 07/02/2009] [Indexed: 11/20/2022]
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40
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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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42
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Han S, Yi H, Yin SJ, Chen ZY, Liu H, Cao ZJ, Wu YL, Li WX. Structural Basis of a Potent Peptide Inhibitor Designed for Kv1.3 Channel, a Therapeutic Target of Autoimmune Disease. J Biol Chem 2008; 283:19058-65. [DOI: 10.1074/jbc.m802054200] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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43
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Beeton C, Smith BJ, Sabo JK, Crossley G, Nugent D, Khaytin I, Chi V, Chandy KG, Pennington MW, Norton RS. The D-Diastereomer of ShK Toxin Selectively Blocks Voltage-gated K+ Channels and Inhibits T Lymphocyte Proliferation. J Biol Chem 2008; 283:988-97. [DOI: 10.1074/jbc.m706008200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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44
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Hu L, Pennington M, Jiang Q, Whartenby KA, Calabresi PA. Characterization of the functional properties of the voltage-gated potassium channel Kv1.3 in human CD4+ T lymphocytes. THE JOURNAL OF IMMUNOLOGY 2007; 179:4563-70. [PMID: 17878353 DOI: 10.4049/jimmunol.179.7.4563] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies have shown that central memory T (T(CM)) cells predominantly use the calcium-dependent potassium channel KCa3.1 during acute activation, whereas effector memory T (T(EM)) cells use the voltage-gated potassium channel Kv1.3. Because Kv1.3-specific pharmacological blockade selectively inhibited anti-CD3-mediated proliferation, whereas naive T cells and T(CM) cells escaped inhibition due to up-regulation of KCa3.1, this difference indicated a potential for selective targeting of the T(EM) population. We examined the effects of pharmacological Kv1.3 blockers and a dominant-negative Kv1.x construct on T cell subsets to assess the specific effects of Kv1.3 blockade. Our studies indicated both T(CM) and T(EM) CD4+ T cells stimulated with anti-CD3 were inhibited by charybdotoxin, which can block both KCa3.1 and Kv1.3, whereas margatoxin and Stichodactyla helianthus toxin, which are more selective Kv1.3 inhibitors, inhibited proliferation and IFN-gamma production only in the T(EM) subset. The addition of anti-CD28 enhanced proliferation of freshly isolated cells and rendered them refractory to S. helianthus, whereas chronically activated T(EM) cell lines appeared to be costimulation independent because Kv1.3 blockers effectively inhibited proliferation and IFN-gamma regardless of second signal. Transduction of CD4+ T cells with dominant-negative Kv1.x led to a higher expression of CCR7+ T(CM) phenotype and a corresponding depletion of T(EM). These data provide further support for Kv1.3 as a selective target of chronically activated T(EM) without compromising naive or T(CM) immune functions. Specific Kv1.3 blockers may be beneficial in autoimmune diseases such as multiple sclerosis in which T(EM) are found in the target organ.
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Affiliation(s)
- Lina Hu
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
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Abstract
One of the functional roles of the corneal epithelial layer is to protect the cornea, lens and other underlying ocular structures from damages caused by environmental insults. It is important for corneal epithelial cells to maintain this function by undergoing continuous renewal through a dynamic process of wound healing. Previous studies in corneal epithelial cells have provided substantial evidence showing that environmental insults, such as ultraviolet (UV) irradiation and other biohazards, can induce stress-related cellular responses resulting in apoptosis and thus interrupt the dynamic process of wound healing. We found that UV irradiation-induced apoptotic effects in corneal epithelial cells are started by the hyperactivation of K+ channels in the cell membrane resulting in a fast loss of intracellular K+ ions. Recent studies provide further evidence indicating that these complex responses in corneal epithelial cells are resulted from the activation of stress-related signaling pathways mediated by K+ channel activity. The effect of UV irradiation on corneal epithelial cell fate shares common signaling mechanisms involving the activation of intracellular responses that are often activated by the stimulation of various cytokines. One piece of evidence for making this distinction is that at early times UV irradiation activates a Kv3.4 channel in corneal epithelial cells to elicit activation of c-Jun N-terminal kinase cascades and p53 activation leading to cell cycle arrest and apoptosis. The hypothetic model is that UV-induced potassium channel hyperactivity as an early event initiates fast cell shrinkages due to the loss of intracellular potassium, resulting in the activation of scaffolding protein kinases and cytoskeleton reorganizations. This review article presents important control mechanisms that determine Kv channel activity-mediated cellular responses in corneal epithelial cells, involving activation of stress-induced signaling pathways, arrests of cell cycle progression and/or induction of apoptosis.
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Affiliation(s)
- Luo Lu
- Department of Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California Los Angeles, Harbor-UCLA Medical Center, CA 90502, USA.
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Pardo LA, Contreras-Jurado C, Zientkowska M, Alves F, Stühmer W. Role of voltage-gated potassium channels in cancer. J Membr Biol 2006; 205:115-24. [PMID: 16362499 DOI: 10.1007/s00232-005-0776-1] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Indexed: 01/12/2023]
Abstract
Ion channels are being associated with a growing number of diseases including cancer. This overview summarizes data on voltage-gated potassium channels (VGKCs) that exhibit oncogenic properties: ether-à-go-go type 1 (Eag1). Normally, Eag1 is expressed almost exclusively in tissue of neural origin, but its ectopic expression leads to uncontrolled proliferation, while inhibition of Eag1 expression produces a concomitant reduction in proliferation. Specific monoclonal antibodies against Eag1 recognize an epitope in over 80% of human tumors of diverse origins, endowing it with diagnostic and therapeutic potential. Eag1 also possesses unique electrophysiological properties that simplify its identification. This is particularly important, as specific blockers of Eag1 currents are not available. Molecular imaging of Eag1 in live tumor models has been accomplished with dye-tagged antibodies using 3-D imaging techniques in the near-infrared spectral range.
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Affiliation(s)
- L A Pardo
- Max-Planck-Institute of Experimental Medicine, Hermann Rein Str. 3, Göttingen, 37075 Germany.
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Gallo EM, Canté-Barrett K, Crabtree GR. Lymphocyte calcium signaling from membrane to nucleus. Nat Immunol 2005; 7:25-32. [PMID: 16357855 DOI: 10.1038/ni1295] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 11/14/2005] [Indexed: 12/14/2022]
Abstract
Ca(2+) signals control a variety of lymphocyte responses, ranging from short-term cytoskeletal modifications to long-term changes in gene expression. The identification of molecules and channels that modulate Ca(2+) entry into T and B lymphocytes has both provided details of the molecular events leading to immune responses and raised controversy. Here we review studies of the pathways that allow Ca(2+) entry, the function of Ca(2+) in the regulation of cell polarity and motility and the principles by which Ca(2+)-dependent transcription regulates lymphocyte function.
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Affiliation(s)
- Elena M Gallo
- Program in Immunology, Stanford University, Stanford, California 94305, USA
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Fernández RG, Leehan JA, Pastrana RF, Muñiz RO. Effect of malnutrition on K+ current in T lymphocytes. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2005; 12:808-13. [PMID: 16002627 PMCID: PMC1182212 DOI: 10.1128/cdli.12.7.808-813.2005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Severe malnutrition in children is frequently associated with infectious diseases. Animal models have been useful for studying the effects of malnutrition. One of the immunosuppressive mechanisms of malnutrition is inhibition of the activation of T lymphocytes. The voltage-dependent K(V) potassium channels are vital for the activation of T lymphocytes. The blockade of K(V) channels inhibits the activation of T lymphocytes. Malnutrition could affect the suitable synthesis of K(V) channels in T lymphocytes, producing changes in the magnitude and/or dependency of the voltage of the K+ current. We reported a significant decrease in the K+ current and activation to a 20 mV more positive membrane potential in T lymphocytes of rats with severe malnutrition. These results indicate that the diminution in the K+ conductance by alteration of K(V) channels in severe malnutrition is one of the mechanisms that inhibit the activation of T lymphocytes.
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Affiliation(s)
- Rafael Godínez Fernández
- Depto. Ingeniería Eléctrica, Universidad Autónoma Metropolitana. Unidad Iztapalapa, Av. San Rafael Atlixco No. 186, Col. Vicentina Iztapalapa, C. P. 09340, México, D. F. Mexico.
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Ambriz-Tututi M, Velázquez-Zamora DA, Urquiza-Marín H, Granados-Soto V. Analysis of the mechanism underlying the peripheral antinociceptive action of sildenafil in the formalin test. Eur J Pharmacol 2005; 512:121-7. [PMID: 15840396 DOI: 10.1016/j.ejphar.2005.01.055] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Revised: 01/24/2005] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
The mechanism of the antinociceptive action of the phosphodiesterase 5 inhibitor, sildenafil, was assessed in the formalin test. Local peripheral ipsilateral, but not contralateral, administration of sildenafil (50-200 microg/paw) produced a dose-related antinociception during both phases of the formalin test. The local peripheral pretreatment with protein kinase G inhibitor peptide (PKG inhibitor, 0.01-1 microg/paw), charybdotoxin (large- and intermediate-conductance Ca2+-activated K+ channel blocker, 0.01-1 microg/paw), apamin (small-conductance Ca2+-activated K+ channel blocker, 0.1-2 microg/paw), tolbutamide (ATP-sensitive K+ channel blocker, 12.5-50 microg/paw), and tetraethylammonium (non-selective voltage-dependent K+ channel blocker, 12.5-50 microg/paw), but not 1H-(1,2,4)-oxadiazolo(4,2-a)quinoxalin-1-one (ODQ, inhibitor of guanylyl cyclase, 12.5-50 microg/paw) or saline, significantly diminished in a dose-dependent manner sildenafil-induced local peripheral antinociception. Given alone, local peripheral administration of inhibitors did not modify formalin-induced nociceptive behavior. Results suggest that sildenafil produces its local peripheral antinociceptive effect via activation of the cyclic GMP-PKG-K+ channel pathway.
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Affiliation(s)
- Mónica Ambriz-Tututi
- Escuela de Químico-Farmacobiología, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
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Abstract
Neurodegeneration induced by excitatory neurotransmitter glutamate is considered to be of particular relevance in several types of acute and chronic neurological impairments ranging from cerebral ischaemia to neuropathological conditions such as motor neuron disease, Alzheimer's, Parkinson's disease and epilepsy. The hyperexcitation of glutamate receptors coupled with calcium overload can be prevented or modulated by using well-established competitive and non-competitive antagonists targeting ion/receptor channels. The exponentially increasing body of pharmacological evidence over the years indicates potential applications of peptide toxins, due to their exquisite subtype selectivity on ion channels and receptors, as lead structures for the development of drugs for the treatment of wide variety of neurological disorders. This review comprehensively highlights the overview of the diversity in the molecular as well as neurobiological mechanisms of different peptide toxins derived from venomous animals with particular reference to neuroprotection. In addition, the potential applications of peptide toxins in the diagnosis and treatment of neurological disorders such as neuromuscular disorders, epilepsy, Alzheimer's and Parkinson's diseases, gliomas and ischaemic stroke and their future prospects in the diagnosis as well as in the therapy are addressed.
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Affiliation(s)
- Wudayagiri Rajendra
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore
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