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Rojas-Palomino J, Gómez-Restrepo A, Salinas-Restrepo C, Segura C, Giraldo MA, Calderón JC. Electrophysiological evaluation of the effect of peptide toxins on voltage-gated ion channels: a scoping review on theoretical and methodological aspects with focus on the Central and South American experience. J Venom Anim Toxins Incl Trop Dis 2024; 30:e20230048. [PMID: 39263598 PMCID: PMC11389830 DOI: 10.1590/1678-9199-jvatitd-2023-0048] [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: 10/09/2023] [Accepted: 05/02/2024] [Indexed: 09/13/2024] Open
Abstract
The effect of peptide toxins on voltage-gated ion channels can be reliably assessed using electrophysiological assays, such as the patch-clamp technique. However, much of the toxinological research done in Central and South America aims at purifying and characterizing biochemical properties of the toxins of vegetal or animal origin, lacking electrophysiological approaches. This may happen due to technical and infrastructure limitations or because researchers are unfamiliar with the techniques and cellular models that can be used to gain information about the effect of a molecule on ion channels. Given the potential interest of many research groups in the highly biodiverse region of Central and South America, we reviewed the most relevant conceptual and methodological developments required to implement the evaluation of the effect of peptide toxins on mammalian voltage-gated ion channels using patch-clamp. For that, we searched MEDLINE/PubMed and SciELO databases with different combinations of these descriptors: "electrophysiology", "patch-clamp techniques", "Ca2+ channels", "K+ channels", "cnidarian venoms", "cone snail venoms", "scorpion venoms", "spider venoms", "snake venoms", "cardiac myocytes", "dorsal root ganglia", and summarized the literature as a scoping review. First, we present the basics and recent advances in mammalian voltage-gated ion channel's structure and function and update the most important animal sources of channel-modulating toxins (e.g. cnidarian and cone snails, scorpions, spiders, and snakes), highlighting the properties of toxins electrophysiologically characterized in Central and South America. Finally, we describe the local experience in implementing the patch-clamp technique using two models of excitable cells, as well as the participation in characterizing new modulators of ion channels derived from the venom of a local spider, a toxins' source less studied with electrophysiological techniques. Fostering the implementation of electrophysiological methods in more laboratories in the region will strengthen our capabilities in many fields, such as toxinology, toxicology, pharmacology, natural products, biophysics, biomedicine, and bioengineering.
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Affiliation(s)
| | - Alejandro Gómez-Restrepo
- Physiology and Biochemistry Research Group -PHYSIS, Faculty of Medicine, University of Antioquia, Medellín, Colombia
| | - Cristian Salinas-Restrepo
- Toxinology, Therapeutic and Food Alternatives Research Group, Faculty of Pharmaceutical and Food Sciences, University of Antioquia, Medellín, Colombia
| | - César Segura
- Malaria Group, Faculty of Medicine, University of Antioquia, Medellín, Colombia
| | - Marco A Giraldo
- Biophysics Group, Institute of Physics, University of Antioquia, Medellín, Colombia
| | - Juan C Calderón
- Physiology and Biochemistry Research Group -PHYSIS, Faculty of Medicine, University of Antioquia, Medellín, Colombia
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Sastre D, Colomer-Molera M, de Benito-Bueno A, Valenzuela C, Fernández-Ballester G, Felipe A. KCNE4-dependent modulation of Kv1.3 pharmacology. Biochem Pharmacol 2024; 226:116368. [PMID: 38880360 DOI: 10.1016/j.bcp.2024.116368] [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: 01/31/2024] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 06/18/2024]
Abstract
The voltage-dependent potassium channel Kv1.3 is a promising therapeutic target for the treatment of autoimmune and chronic inflammatory disorders. Kv1.3 blockers are effective in treating multiple sclerosis (fampridine) and psoriasis (dalazatide). However, most Kv1.3 pharmacological antagonists are not specific enough, triggering potential side effects and limiting their therapeutic use. Functional Kv are oligomeric complexes in which the presence of ancillary subunits shapes their function and pharmacology. In leukocytes, Kv1.3 associates with KCNE4, which reduces the surface abundance and enhances the inactivation of the channel. This mechanism exerts profound consequences on Kv1.3-related physiological responses. Because KCNE peptides alter the pharmacology of Kv channels, we studied the effects of KCNE4 on Kv1.3 pharmacology to gain insights into pharmacological approaches. To that end, we used margatoxin, which binds the channel pore from the extracellular space, and Psora-4, which blocks the channel from the intracellular side. While KCNE4 apparently did not alter the affinity of either margatoxin or Psora-4, it slowed the inhibition kinetics of the latter in a stoichiometry-dependent manner. The results suggested changes in the Kv1.3 architecture in the presence of KCNE4. The data indicated that while the outer part of the channel mouth remains unaffected, KCNE4 disturbs the intracellular architecture of the complex. Various leukocyte types expressing different Kv1.3/KCNE4 configurations participate in the immune response. Our data provide evidence that the presence of these variable architectures, which affect both the structure of the complex and their pharmacology, should be considered when developing putative therapeutic approaches.
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Affiliation(s)
- Daniel Sastre
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Magalí Colomer-Molera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain
| | | | - Carmen Valenzuela
- Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, 28029 Madrid, Spain
| | | | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain.
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Shakeel K, Olamendi-Portugal T, Naseem MU, Becerril B, Zamudio FZ, Delgado-Prudencio G, Possani LD, Panyi G. Of Seven New K + Channel Inhibitor Peptides of Centruroides bonito, α-KTx 2.24 Has a Picomolar Affinity for Kv1.2. Toxins (Basel) 2023; 15:506. [PMID: 37624263 PMCID: PMC10467108 DOI: 10.3390/toxins15080506] [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: 07/30/2023] [Revised: 08/07/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023] Open
Abstract
Seven new peptides denominated CboK1 to CboK7 were isolated from the venom of the Mexican scorpion Centruroides bonito and their primary structures were determined. The molecular weights ranged between 3760.4 Da and 4357.9 Da, containing 32 to 39 amino acid residues with three putative disulfide bridges. The comparison of amino acid sequences with known potassium scorpion toxins (KTx) and phylogenetic analysis revealed that CboK1 (α-KTx 10.5) and CboK2 (α-KTx 10.6) belong to the α-KTx 10.x subfamily, whereas CboK3 (α-KTx 2.22), CboK4 (α-KTx 2.23), CboK6 (α-KTx 2.21), and CboK7 (α-KTx 2.24) bear > 95% amino acid similarity with members of the α-KTx 2.x subfamily, and CboK5 is identical to Ce3 toxin (α-KTx 2.10). Electrophysiological assays demonstrated that except CboK1, all six other peptides blocked the Kv1.2 channel with Kd values in the picomolar range (24-763 pM) and inhibited the Kv1.3 channel with comparatively less potency (Kd values between 20-171 nM). CboK3 and CboK4 inhibited less than 10% and CboK7 inhibited about 42% of Kv1.1 currents at 100 nM concentration. Among all, CboK7 showed out-standing affinity for Kv1.2 (Kd = 24 pM), as well as high selectivity over Kv1.3 (850-fold) and Kv1.1 (~6000-fold). These characteristics of CboK7 may provide a framework for developing tools to treat Kv1.2-related channelopathies.
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Affiliation(s)
- Kashmala Shakeel
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary; (K.S.); (M.U.N.)
| | - Timoteo Olamendi-Portugal
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary; (K.S.); (M.U.N.)
| | - Baltazar Becerril
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Fernando Z. Zamudio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Gustavo Delgado-Prudencio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Lourival Domingos Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary; (K.S.); (M.U.N.)
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Olivas-Aguirre M, Cruz-Aguilar LH, Pottosin I, Dobrovinskaya O. Reduction of Ca 2+ Entry by a Specific Block of KCa3.1 Channels Optimizes Cytotoxic Activity of NK Cells against T-ALL Jurkat Cells. Cells 2023; 12:2065. [PMID: 37626875 PMCID: PMC10453324 DOI: 10.3390/cells12162065] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
Degranulation mediated killing mechanism by NK cells is dependent on store-operated Ca2+ entry (SOCE) and has optimum at moderate intracellular Ca2+ elevations so that partial block of SOCE optimizes the killing process. In this study, we tested the effect of the selective blocker of KCa3.1 channel NS6180 on SOCE and the killing efficiency of NK cells from healthy donors and NK-92 cells against T-ALL cell line Jurkat. Patch-clamp analysis showed that only one-quarter of resting NK cells functionally express KCa3.1 current, which increases 3-fold after activation by interleukins 15 and 2. Nevertheless, blockage of KCa3.1 significantly reduced SOCE and intracellular Ca2+ rise induced by IL-15 or target cell recognition. NS6180 (1 μM) decreased NK degranulation at zero time of coculture with Jurkat cells but already after 1 h, the degranulation reached the same level as in the control. Monitoring of target cell death by flow cytometry and confocal microscopy demonstrated that NS6180 significantly improved the killing ability of NK cells after 1 h in coculture with Jurkat cells and increased the Jurkat cell fraction with apoptotic and necrotic markers. Our data evidence a strong dependence of SOCE on KCa3.1 activity in NK cells and that KCa3.1 specific block can improve NK cytotoxicity.
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Affiliation(s)
- Miguel Olivas-Aguirre
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima 28045, Mexico
- Division of Exact, Natural and Technological Sciences, South University Center (CUsur), University of Guadalajara, Guzmán City 49000, Mexico
| | - Laura Hadit Cruz-Aguilar
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima 28045, Mexico
| | - Igor Pottosin
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima 28045, Mexico
| | - Oxana Dobrovinskaya
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima 28045, Mexico
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Orlov NA, Kryukova EV, Efremenko AV, Yakimov SA, Toporova VA, Kirpichnikov MP, Nekrasova OV, Feofanov AV. Interactions of the Kv1.1 Channel with Peptide Pore Blockers: A Fluorescent Analysis on Mammalian Cells. MEMBRANES 2023; 13:645. [PMID: 37505011 PMCID: PMC10383195 DOI: 10.3390/membranes13070645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/29/2023]
Abstract
The voltage-gated potassium channel Kv1.1, which is abundant in the CNS and peripheral nervous system, controls neuronal excitability and neuromuscular transmission and mediates a number of physiological functions in non-excitable cells. The development of some diseases is accompanied by changes in the expression level and/or activity of the channels in particular types of cells. To meet the requirements of studies related to the expression and localization of the Kv1.1 channels, we report on the subnanomolar affinity of hongotoxin 1 N-terminally labeled with Atto 488 fluorophore (A-HgTx) for the Kv1.1 channel and its applicability for fluorescent imaging of the channel in living cells. Taking into consideration the pharmacological potential of the Kv1.1 channel, a fluorescence-based analytical system was developed for the study of peptide ligands that block the ion conductivity of Kv1.1 and are potentially able to correct abnormal activity of the channel. The system is based on analysis of the competitive binding of the studied compounds and A-HgTx to the mKate2-tagged human Kv1.1 (S369T) channel, expressed in the plasma membrane of Neuro2a cells. The system was validated by measuring the affinities of the known Kv1.1-channel peptide blockers, such as agitoxin 2, kaliotoxin 1, hongotoxin 1, and margatoxin. Peptide pore blocker Ce1, from the venom of the scorpion Centruroides elegans, was shown to possess a nanomolar affinity for the Kv1.1 channel. It is reported that interactions of the Kv1.1 channel with the studied peptide blockers are not affected by the transition of the channel from the closed to open state. The conclusion is made that the structural rearrangements accompanying the channel transition into the open state do not change the conformation of the P-loop (including the selectivity filter) involved in the formation of the binding site of the peptide pore blockers.
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Affiliation(s)
- Nikita A Orlov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Elena V Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Anastasia V Efremenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Sergey A Yakimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Victoria A Toporova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Mikhail P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Oksana V Nekrasova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Alexey V Feofanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
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Angi B, Muccioli S, Szabò I, Leanza L. A Meta-Analysis Study to Infer Voltage-Gated K+ Channels Prognostic Value in Different Cancer Types. Antioxidants (Basel) 2023; 12:antiox12030573. [PMID: 36978819 PMCID: PMC10045123 DOI: 10.3390/antiox12030573] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/02/2023] Open
Abstract
Potassium channels are often highly expressed in cancer cells with respect to healthy ones, as they provide proliferative advantages through modulating membrane potential, calcium homeostasis, and various signaling pathways. Among potassium channels, Shaker type voltage-gated Kv channels are emerging as promising pharmacological targets in oncology. Here, we queried publicly available cancer patient databases to highlight if a correlation exists between Kv channel expression and survival rate in five different cancer types. By multiple gene comparison analysis, we found a predominant expression of KCNA2, KCNA3, and KCNA5 with respect to the other KCNA genes in skin cutaneous melanoma (SKCM), uterine corpus endometrial carcinoma (UCEC), stomach adenocarcinoma (STAD), lung adenocarcinoma (LUAD), and lung squamous cell carcinoma (LUSC). This analysis highlighted a prognostic role of KCNA3 and KCNA5 in SKCM, LUAD, LUSC, and STAD, respectively. Interestingly, KCNA3 was associated with a positive prognosis in SKCM and LUAD but not in LUSC. Results obtained by the analysis of KCNA3-related differentially expressed genes (DEGs); tumor immune cell infiltration highlighted differences that may account for such differential prognosis. A meta-analysis study was conducted to investigate the role of KCNA channels in cancer using cancer patients’ datasets. Our study underlines a promising correlation between Kv channel expression in tumor cells, in infiltrating immune cells, and survival rate.
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Wang ZW, Trussell LO, Vedantham K. Regulation of Neurotransmitter Release by K + Channels. ADVANCES IN NEUROBIOLOGY 2023; 33:305-331. [PMID: 37615872 DOI: 10.1007/978-3-031-34229-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
K+ channels play potent roles in the process of neurotransmitter release by influencing the action potential waveform and modulating neuronal excitability and release probability. These diverse effects of K+ channel activation are ensured by the wide variety of K+ channel genes and their differential expression in different cell types. Accordingly, a variety of K+ channels have been implicated in regulating neurotransmitter release, including the Ca2+- and voltage-gated K+ channel Slo1 (also known as BK channel), voltage-gated K+ channels of the Kv3 (Shaw-type), Kv1 (Shaker-type), and Kv7 (KCNQ) families, G-protein-gated inwardly rectifying K+ (GIRK) channels, and SLO-2 (a Ca2+-. Cl-, and voltage-gated K+ channel in C. elegans). These channels vary in their expression patterns, subcellular localization, and biophysical properties. Their roles in neurotransmitter release may also vary depending on the synapse and physiological or experimental conditions. This chapter summarizes key findings about the roles of K+ channels in regulating neurotransmitter release.
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Affiliation(s)
- Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA.
| | - Laurence O Trussell
- Oregon Hearing Research Center & Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Kiranmayi Vedantham
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
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Varanita T, Angi B, Scattolini V, Szabo I. Kv1.3 K + Channel Physiology Assessed by Genetic and Pharmacological Modulation. Physiology (Bethesda) 2023; 38:0. [PMID: 35998249 DOI: 10.1152/physiol.00010.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Potassium channels are widespread over all kingdoms and play an important role in the maintenance of cellular ionic homeostasis. Kv1.3 is a voltage-gated potassium channel of the Shaker family with a wide tissue expression and a well-defined pharmacology. In recent decades, experiments mainly based on pharmacological modulation of Kv1.3 have highlighted its crucial contribution to different fundamental processes such as regulation of proliferation, apoptosis, and metabolism. These findings link channel function to various pathologies ranging from autoimmune diseases to obesity and cancer. In the present review, we briefly summarize studies employing Kv1.3 knockout animal models to confirm such roles and discuss the findings in comparison to the results obtained by pharmacological modulation of Kv1.3 in various pathophysiological settings. We also underline how these studies contributed to our understanding of channel function in vivo and propose possible future directions.
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Affiliation(s)
| | - Beatrice Angi
- Department of Biology, University of Padova, Padova, Italy
| | | | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy
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ShK-Domain-Containing Protein from a Parasitic Nematode Modulates Drosophila melanogaster Immunity. Pathogens 2022; 11:pathogens11101094. [PMID: 36297151 PMCID: PMC9610955 DOI: 10.3390/pathogens11101094] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/19/2022] [Accepted: 09/21/2022] [Indexed: 11/16/2022] Open
Abstract
A key component to understanding host–parasite interactions is the molecular crosstalk between host and parasite. Excreted/secreted products (ESPs) released by parasitic nematodes play an important role in parasitism. They can directly damage host tissue and modulate host defense. Steinernema carpocapsae, a well-studied parasite of insects releases approximately 500 venom proteins as part of the infection process. Though the identity of these proteins is known, few have been studied in detail. One protein family present in the ESPs released by these nematodes is the ShK family. We studied the most abundant ShK-domain-containing protein in S. carpocapsae ESPs, Sc-ShK-1, to investigate its effects in a fruit fly model. We found that Sc-ShK-1 is toxic under high stress conditions and negatively affects the health of fruit flies. We have shown that Sc-ShK-1 contributes to host immunomodulation in bacterial co-infections resulting in increased mortality and microbial growth. This study provides an insight on ShK-domain-containing proteins from nematodes and suggests these proteins may play an important role in host–parasite interactions.
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Naseem MU, Carcamo-Noriega E, Beltrán-Vidal J, Borrego J, Szanto TG, Zamudio FZ, Delgado-Prudencio G, Possani LD, Panyi G. Cm28, a scorpion toxin having a unique primary structure, inhibits KV1.2 and KV1.3 with high affinity. J Gen Physiol 2022; 154:213282. [PMID: 35699659 PMCID: PMC9202693 DOI: 10.1085/jgp.202213146] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/23/2022] [Indexed: 02/03/2023] Open
Abstract
The Cm28 in the venom of Centruroides margaritatus is a short peptide consisting of 27 amino acid residues with a mol wt of 2,820 D. Cm28 has <40% similarity with other known α-KTx from scorpions and lacks the typical functional dyad (lysine-tyrosine) required to block KV channels. However, its unique sequence contains the three disulfide-bond traits of the α-KTx scorpion toxin family. We propose that Cm28 is the first example of a new subfamily of α-KTxs, registered with the systematic number α-KTx32.1. Cm28 inhibited voltage-gated K+ channels KV1.2 and KV1.3 with Kd values of 0.96 and 1.3 nM, respectively. There was no significant shift in the conductance-voltage (G-V) relationship for any of the channels in the presence of toxin. Toxin binding kinetics showed that the association and dissociation rates are consistent with a bimolecular interaction between the peptide and the channel. Based on these, we conclude that Cm28 is not a gating modifier but rather a pore blocker. In a selectivity assay, Cm28 at 150 nM concentration (>100× Kd value for KV1.3) did not inhibit KV1.5, KV11.1, KCa1.1, and KCa3.1 K+ channels; NaV1.5 and NaV1.4 Na+ channels; or the hHV1 H+ channel but blocked ∼27% of the KV1.1 current. In a biological functional assay, Cm28 strongly inhibited the expression of the activation markers interleukin-2 receptor and CD40 ligand in anti-CD3-activated human CD4+ effector memory T lymphocytes. Cm28, due to its unique structure, may serve as a template for the generation of novel peptides targeting KV1.3 in autoimmune diseases.
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Affiliation(s)
- Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Edson Carcamo-Noriega
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - José Beltrán-Vidal
- Grupo de Investigaciones Herpetológicas y Toxinológicas, Centro de Investigaciones Biomédicas, Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Universidad del Cauca, Popayán, Colombia
| | - Jesus Borrego
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Tibor G. Szanto
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Fernando Z. Zamudio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Gustavo Delgado-Prudencio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Lourival D. Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary,Correspondence to Gyorgy Panyi:
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sVmKTx, a transcriptome analysis-based synthetic peptide analogue of Vm24, inhibits Kv1.3 channels of human T cells with improved selectivity. Biochem Pharmacol 2022; 199:115023. [PMID: 35358481 DOI: 10.1016/j.bcp.2022.115023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 12/13/2022]
Abstract
Kv1.3 K+ channels play a central role in the regulation of T cell activation and Ca2+ signaling under physiological and pathophysiological conditions. Peptide toxins targeting Kv1.3 have a significant therapeutic potential in the treatment of autoimmune diseases; thus, the discovery of new toxins is highly motivated. Based on the transcriptome analysis of the venom gland of V. mexicanus smithi a novel synthetic peptide, sVmKTx was generated, containing 36 amino acid residues. sVmKTx shows high sequence similarity to Vm24, a previously characterized peptide from the same species, but contains a Glu at position 32 as opposed to Lys32 in Vm24. Vm24 inhibits Kv1.3 with high affinity (Kd = 2.9 pM). However, it has limited selectivity (~1,500-fold) for Kv1.3 over hKv1.2, hKCa3.1, and mKv1.1. sVmKTx displays reduced Kv1.3 affinity (Kd = 770 pM) but increased selectivity for Kv1.3 over hKv1.2 (~9,000-fold) as compared to Vm24, other channels tested in the panel (hKCa3.1, hKv1.1, hKv1.4, hKv1.5, rKv2.1, hKv11.1, hKCa1.1, hNav1.5) were practically insensitive to the toxin at 2.5 μM. Molecular dynamics simulations showed that introduction of a Glu instead of Lys at position 32 led to a decreased structural fluctuation of the N-terminal segment of sVmKTx, which may explain its increased selectivity for Kv1.3. sVmKTx at 100 nM concentration decreased the expression level of the Ca2+ -dependent T cell activation marker, CD40 ligand. The high affinity block of Kv1.3 and increased selectivity over the natural peptide makes sVmKTx a potential candidate for Kv1.3 blockade-mediated treatment of autoimmune diseases.
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Sebestyén V, Nagy É, Mocsár G, Volkó J, Szilágyi O, Kenesei Á, Panyi G, Tóth K, Hajdu P, Vámosi G. Role of C-Terminal Domain and Membrane Potential in the Mobility of Kv1.3 Channels in Immune Synapse Forming T Cells. Int J Mol Sci 2022; 23:ijms23063313. [PMID: 35328733 PMCID: PMC8952507 DOI: 10.3390/ijms23063313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 02/01/2023] Open
Abstract
Voltage-gated Kv1.3 potassium channels are essential for maintaining negative membrane potential during T-cell activation. They interact with membrane-associated guanylate kinases (MAGUK-s) via their C-terminus and with TCR/CD3, leading to enrichment at the immunological synapse (IS). Molecular interactions and mobility may impact each other and the function of these proteins. We aimed to identify molecular determinants of Kv1.3 mobility, applying fluorescence correlation spectroscopy on human Jurkat T-cells expressing WT, C-terminally truncated (ΔC), and non-conducting mutants of mGFP-Kv1.3. ΔC cannot interact with MAGUK-s and is not enriched at the IS, whereas cells expressing the non-conducting mutant are depolarized. Here, we found that in standalone cells, mobility of ΔC increased relative to the WT, likely due to abrogation of interactions, whereas mobility of the non-conducting mutant decreased, similar to our previous observations on other membrane proteins in depolarized cells. At the IS formed with Raji B-cells, mobility of WT and non-conducting channels, unlike ΔC, was lower than outside the IS. The Kv1.3 variants possessing an intact C-terminus had lower mobility in standalone cells than in IS-engaged cells. This may be related to the observed segregation of F-actin into a ring-like structure at the periphery of the IS, leaving much of the cell almost void of F-actin. Upon depolarizing treatment, mobility of WT and ΔC channels decreased both in standalone and IS-engaged cells, contrary to non-conducting channels, which themselves caused depolarization. Our results support that Kv1.3 is enriched at the IS via its C-terminal region regardless of conductivity, and that depolarization decreases channel mobility.
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Affiliation(s)
- Veronika Sebestyén
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Éva Nagy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Gábor Mocsár
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Julianna Volkó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Orsolya Szilágyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Ádám Kenesei
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - György Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
| | - Katalin Tóth
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
- Division Biophysics of Macromolecules, German Cancer Research Center, D-69120 Heidelberg, Germany
| | - Péter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
- Department of Biophysics and Cell Biology, Faculty of Dentistry, University of Debrecen, H-4032 Debrecen, Hungary
- Correspondence: (P.H.); (G.V.)
| | - György Vámosi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (V.S.); (É.N.); (G.M.); (J.V.); (O.S.); (Á.K.); (G.P.); (K.T.)
- Correspondence: (P.H.); (G.V.)
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GFP-Margatoxin, a Genetically Encoded Fluorescent Ligand to Probe Affinity of Kv1.3 Channel Blockers. Int J Mol Sci 2022; 23:ijms23031724. [PMID: 35163644 PMCID: PMC8835862 DOI: 10.3390/ijms23031724] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 02/01/2023] Open
Abstract
Peptide pore blockers and their fluorescent derivatives are useful molecular probes to study the structure and functions of the voltage-gated potassium Kv1.3 channel, which is considered as a pharmacological target in the treatment of autoimmune and neurological disorders. We present Kv1.3 fluorescent ligand, GFP-MgTx, constructed on the basis of green fluorescent protein (GFP) and margatoxin (MgTx), the peptide, which is widely used in physiological studies of Kv1.3. Expression of the fluorescent ligand in E. coli cells resulted in correctly folded and functionally active GFP-MgTx with a yield of 30 mg per 1 L of culture. Complex of GFP-MgTx with the Kv1.3 binding site is reported to have the dissociation constant of 11 ± 2 nM. GFP-MgTx as a component of an analytical system based on the hybrid KcsA-Kv1.3 channel is shown to be applicable to recognize Kv1.3 pore blockers of peptide origin and to evaluate their affinities to Kv1.3. GFP-MgTx can be used in screening and pre-selection of Kv1.3 channel blockers as potential drug candidates.
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Tajti G, Szanto TG, Csoti A, Racz G, Evaristo C, Hajdu P, Panyi G. Immunomagnetic separation is a suitable method for electrophysiology and ion channel pharmacology studies on T cells. Channels (Austin) 2021; 15:53-66. [PMID: 33356811 PMCID: PMC7781520 DOI: 10.1080/19336950.2020.1859753] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/01/2020] [Accepted: 12/01/2020] [Indexed: 12/11/2022] Open
Abstract
Ion channels play pivotal role in the physiological and pathological function of immune cells. As immune cells represent a functionally diverse population, subtype-specific functional studies, such as single-cell electrophysiology require proper subset identification and separation. Magnetic-activated cell sorting (MACS) techniques provide an alternative to fluorescence-activated cell sorting (FACS), however, the potential impact of MACS-related beads on the biophysical and pharmacological properties of the ion channels were not studied yet. We studied the aforementioned properties of the voltage-gated Kv1.3 K+ channel in activated CD4+ T-cells as well as the membrane capacitance using whole-cell patch-clamp following immunomagnetic positive separation, using the REAlease® kit. This kit allows three experimental configurations: bead-bound configuration, bead-free configuration following the removal of magnetic beads, and the label-free configuration following removal of CD4 recognizing antibody fragments. As controls, we used FACS separation as well as immunomagnetic negative selection. The membrane capacitance and of the biophysical parameters of Kv1.3 gating, voltage-dependence of steady-state activation and inactivation kinetics of the current were not affected by the presence of MACS-related compounds on the cell surface. We found subtle differences in the activation kinetics of the Kv1.3 current that could not be explained by the presence of MACS-related compounds. Neither the equilibrium block of Kv1.3 by TEA+ or charybdotoxin (ChTx) nor the kinetics of ChTx block are affected by the presence of the magnetics beads on the cell surface. Based on our results MACS is a suitable method to separate cells for studying ion channels in non-excitable cells, such as T-lymphocytes.
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Affiliation(s)
- Gabor Tajti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tibor Gabor Szanto
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Agota Csoti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Greta Racz
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - César Evaristo
- R&D Reagents Chemical Biology, Miltenyi Biotec B.V. & Co. KG, Bergisch Gladbach, Germany
| | - Peter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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15
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Naseem MU, Tajti G, Gaspar A, Szanto TG, Borrego J, Panyi G. Optimization of Pichia pastoris Expression System for High-Level Production of Margatoxin. Front Pharmacol 2021; 12:733610. [PMID: 34658872 PMCID: PMC8511391 DOI: 10.3389/fphar.2021.733610] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/30/2021] [Indexed: 11/16/2022] Open
Abstract
Margatoxin (MgTx) is a high-affinity blocker of voltage-gated potassium (Kv) channels. It inhibits Kv1.1–Kv1.3 ion channels in picomolar concentrations. This toxin is widely used to study physiological function of Kv ion channels in various cell types, including immune cells. Isolation of native MgTx in large quantities from scorpion venom is not affordable. Chemical synthesis and recombinant production in Escherichia coli need in vitro oxidative refolding for proper disulfide bond formation, resulting in a very low yield of peptide production. The Pichia pastoris expression system offers an economical approach to overcome all these limitations and gives a higher yield of correctly refolded recombinant peptides. In this study, improved heterologous expression of recombinant MgTx (rMgTx) in P. pastoris was obtained by using preferential codons, selecting the hyper-resistant clone against Zeocin, and optimizing the culturing conditions. About 36 ± 4 mg/L of >98% pure His-tagged rMgTx (TrMgTx) was produced, which is a threefold higher yield than has been previously reported. Proteolytic digestion of TrMgTx with factor Xa generated untagged rMgTx (UrMgTx). Both TrMgTx and UrMgTx blocked the Kv1.2 and Kv1.3 currents (patch-clamp) (Kd for Kv1.2 were 64 and 14 pM, and for Kv1.3, 86 and 50 pM, respectively) with comparable potency to the native MgTx. The analysis of the binding kinetics showed that TrMgTx had a lower association rate than UrMgTx for both Kv1.2 and Kv1.3. The dissociation rate of both the analogues was the same for Kv1.3. However, in the case of Kv1.2, TrMgTx showed a much higher dissociation rate with full recovery of the block than UrMgTx. Moreover, in a biological functional assay, both peptides significantly downregulated the expression of early activation markers IL2R and CD40L in activated CD4+ TEM lymphocytes whose activation was Kv1.3 dependent. In conclusion, the authors report that the Pichia expression system is a powerful method to produce disulfide-rich peptides, the overexpression of which could be enhanced noticeably through optimization strategies, making it more cost-effective. Since the presence of the His-tag on rMgTx only mildly altered the block equilibrium and binding kinetics, recombinant toxins could be used in ion channel research without removing the tag and could thus reduce the cost and time demand for toxin production.
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Affiliation(s)
- Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gabor Tajti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Gaspar
- Department of Inorganic and Analytical Chemistry, Faculty of Science and Technology, Institute of Chemistry, University of Debrecen, Debrecen, Hungary
| | - Tibor G Szanto
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Jesús Borrego
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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16
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Matsumura K, Yokogawa M, Osawa M. Peptide Toxins Targeting KV Channels. Handb Exp Pharmacol 2021; 267:481-505. [PMID: 34117930 DOI: 10.1007/164_2021_500] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A number of peptide toxins isolated from animals target potassium ion (K+) channels. Many of them are particularly known to inhibit voltage-gated K+ (KV) channels and are mainly classified into pore-blocking toxins or gating-modifier toxins. Pore-blocking toxins directly bind to the ion permeation pores of KV channels, thereby physically occluding them. In contrast, gating-modifier toxins bind to the voltage-sensor domains of KV channels, modulating their voltage-dependent conformational changes. These peptide toxins are useful molecular tools in revealing the structure-function relationship of KV channels and have potential for novel treatments for diseases related to KV channels. This review focuses on the inhibition mechanism of pore-blocking and gating-modifier toxins that target KV channels.
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Affiliation(s)
- Kazuki Matsumura
- Graduate School of Pharmaceutical Sciences, Keio University, Tokyo, Japan
| | - Mariko Yokogawa
- Graduate School of Pharmaceutical Sciences, Keio University, Tokyo, Japan
| | - Masanori Osawa
- Graduate School of Pharmaceutical Sciences, Keio University, Tokyo, Japan.
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Colombian Scorpion Centruroides margaritatus: Purification and Characterization of a Gamma Potassium Toxin with Full-Block Activity on the hERG1 Channel. Toxins (Basel) 2021; 13:toxins13060407. [PMID: 34201318 PMCID: PMC8273696 DOI: 10.3390/toxins13060407] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 05/31/2021] [Accepted: 06/04/2021] [Indexed: 01/06/2023] Open
Abstract
The Colombian scorpion Centruroides margaritatus produces a venom considered of low toxicity. Nevertheless, there are known cases of envenomation resulting in cardiovascular disorders, probably due to venom components that target ion channels. Among them, the humanether-à-go-go-Related gene (hERG1) potassium channels are critical for cardiac action potential repolarization and alteration in its functionality are associated with cardiac disorders. This work describes the purification and electrophysiological characterization of a Centruroides margaritatus venom component acting on hERG1 channels, the CmERG1 toxin. This novel peptide is composed of 42 amino acids with a MW of 4792.88 Da, folded by four disulfide bonds and it is classified as member number 10 of the γ-KTx1 toxin family. CmERG1 inhibits hERG1 currents with an IC50 of 3.4 ± 0.2 nM. Despite its 90.5% identity with toxin ɣ-KTx1.1, isolated from Centruroides noxius, CmERG1 completely blocks hERG1 current, suggesting a more stable plug of the hERG channel, compared to that formed by other ɣ-KTx.
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18
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Kudryashova KS, Nekrasova OV, Kirpichnikov MP, Feofanov AV. Chimeras of KcsA and Kv1 as a bioengineering tool to study voltage-gated potassium channels and their ligands. Biochem Pharmacol 2021; 190:114646. [PMID: 34090876 DOI: 10.1016/j.bcp.2021.114646] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 11/28/2022]
Abstract
Chimeric potassium channels KcsA-Kv1, which are among the most intensively studied hybrid membrane proteins to date, were constructed by replacing a part of the pore domain of bacterial potassium channel KcsA (K channel of streptomyces A) with corresponding regions of the mammalian voltage-gated potassium channels belonging to the Kv1 subfamily. In this way, the pore blocker binding site of Kv1 channels was transferred to KcsA, opening up possibility to use the obtained hybrids as receptors of Kv1-channel pore blockers of different origin. In this review the recent progress in KcsA-Kv1 channel design and applications is discussed with a focus on the development of new assays for studying interactions of pore blockers with the channels. A summary of experimental data is presented demonstrating that hybrid channels reproduce the blocker-binding profiles of parental Kv1 channels. It is overviewed how the KcsA-Kv1 chimeras are used to get new insight into the structure of potassium channels, to determine molecular basis for high affinity and selectivity of binding of peptide blockers to Kv1 channels, as well as to identify new peptide ligands.
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Affiliation(s)
- Ksenia S Kudryashova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Oksana V Nekrasova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia.
| | - Mikhail P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, 119992 Moscow, Russia
| | - Alexey V Feofanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, 119992 Moscow, Russia
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Liu J, Lv XW, Zhang L, Wang H, Li J, Wu B. Review on Biological Characteristics of Kv1.3 and Its Role in Liver Diseases. Front Pharmacol 2021; 12:652508. [PMID: 34093186 PMCID: PMC8176307 DOI: 10.3389/fphar.2021.652508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/23/2021] [Indexed: 01/30/2023] Open
Abstract
The liver accounts for the largest proportion of macrophages in all solid organs of the human body. Liver macrophages are mainly composed of cytolytic cells inherent in the liver and mononuclear macrophages recruited from the blood. Monocytes recruitment occurs mainly in the context of liver injury and inflammation and can be recruited into the liver and achieve a KC-like phenotype. During the immune response of the liver, macrophages/KC cells release inflammatory cytokines and infiltrate into the liver, which are considered to be the common mechanism of various liver diseases in the early stage. Meanwhile, macrophages/KC cells form an interaction network with other liver cells, which can affect the occurrence and progression of liver diseases. From the perspective of liver disease treatment, knowing the full spectrum of macrophage activation, the underlying molecular mechanisms, and their implication in either promoting liver disease progression or repairing injured liver tissue is highly relevant from a therapeutic point of view. Kv1.3 is a subtype of the voltage-dependent potassium channel, whose function is closely related to the regulation of immune cell function. At present, there are few studies on the relationship between Kv1.3 and liver diseases, and the application of its blockers as a potential treatment for liver diseases has not been reported. This manuscript reviewed the physiological characteristics of Kv1.3, the relationship between Kv1.3 and cell proliferation and apoptosis, and the role of Kv1.3 in a variety of liver diseases, so as to provide new ideas and strategies for the prevention and treatment of liver diseases. In short, by understanding the role of Kv1.3 in regulating the functions of immune cells such as macrophages, selective blockers of Kv1.3 or compounds with similar functions can be applied to alleviate the progression of liver diseases and provide new ideas for the prevention and treatment of liver diseases.
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Affiliation(s)
- Junda Liu
- First Affiliated Hospital of Anhui Medical University, Hefei, China.,School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Xiong-Wen Lv
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Lei Zhang
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Hua Wang
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Baoming Wu
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
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Inhibition of inflammatory cytokine production and proliferation in macrophages by Kunitz-type inhibitors from Echinococcus granulosus. Mol Biochem Parasitol 2021; 242:111351. [PMID: 33428949 DOI: 10.1016/j.molbiopara.2021.111351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/21/2020] [Accepted: 01/04/2021] [Indexed: 10/22/2022]
Abstract
The genus Echinococcus of cestode parasites includes important pathogens of humans and livestock animals. Transcriptomic and genomic studies on E. granulosus and E. multilocularis uncovered striking expansion of monodomain Kunitz proteins. This expansion is accompanied by the specialization of some family members away from the ancestral protease inhibition function to fulfill cation channel blockade functions. Since cation channels are involved in immune processes, we tested the effects on macrophage physiology of two E. granulosus Kunitz-type inhibitors of voltage-activated cation channels (Kv) that are close paralogs. Both inhibitors, EgKU-1 and EgKU-4, inhibited production of the Th1/Th17 cytokine subunit IL-12/23p40 by macrophages stimulated with the TLR4 agonist LPS. In addition, EgKU-4 but not EgKU-1 inhibited production of the inflammatory cytokine IL-6. These activities were not displayed by EgKU-3, a family member that is a protease inhibitor without known activity on cation channels. EgKU-4 potently inhibited macrophage proliferation in response to M-CSF, whereas EgKU-1 displayed similar activity but with much lower potency, similar to EgKU-3. We discuss structural differences, including a heavily cationic C-terminal extension present in EgKU-4 but not in EgKU-1, that may explain the differential activities of the two close paralogs.
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21
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Krishnarjuna B, Sunanda P, Villegas-Moreno J, Csoti A, A V Morales R, Wai DCC, Panyi G, Prentis P, Norton RS. A disulfide-stabilised helical hairpin fold in acrorhagin I: An emerging structural motif in peptide toxins. J Struct Biol 2020; 213:107692. [PMID: 33387653 DOI: 10.1016/j.jsb.2020.107692] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/14/2020] [Accepted: 12/24/2020] [Indexed: 12/22/2022]
Abstract
Acrorhagin I (U-AITX-Aeq5a) is a disulfide-rich peptide identified in the aggressive organs (acrorhagi) of the sea anemone Actinia equina. Previous studies (Toxicon 2005, 46:768-74) found that the peptide is toxic in crabs, although the structural and functional properties of acrorhagin I have not been reported. In this work, an Escherichia coli (BL21 strain) expression system was established for the preparation of 13C,15N-labelled acrorhagin I, and the solution structure was determined using NMR spectroscopy. Structurally, acrorhagin I is similar to B-IV toxin from the marine worm Cerebratulus lacteus (PDB id 1VIB), with a well-defined helical hairpin structure stabilised by four intramolecular disulfide bonds. The recombinant peptide was tested in patch-clamp electrophysiology assays against voltage-gated potassium and sodium channels, and in bacterial and fungal growth inhibitory assays and haemolytic assays. Acrorhagin I was not active against any of the ion channels tested and showed no activity in functional assays, indicating that this peptide may possess a different biological function. Metal ion interaction studies using NMR spectroscopy showed that acrorhagin I bound zinc and nickel, suggesting that its function might be modulated by metal ions or that it may be involved in regulating metal ion levels and their transport. The similarity between the structure of acrorhagin I and that of B-IV toxin from a marine worm suggests that this fold may prove to be a recurring motif in disulfide-rich peptides from marine organisms.
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Affiliation(s)
- Bankala Krishnarjuna
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Punnepalli Sunanda
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Jessica Villegas-Moreno
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia; Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Agota Csoti
- Department of Biophysics and Cell Biology, University of Debrecen, 4032 Debrecen, Hungary; MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, 4032 Debrecen, Hungary
| | - Rodrigo A V Morales
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Dorothy C C Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, University of Debrecen, 4032 Debrecen, Hungary; MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, 4032 Debrecen, Hungary
| | - Peter Prentis
- School of Earth, Environmental and Biological Sciences, Science and Engineering Faculty, Queensland University of Technology, Brisbane, Australia; Institute for Future Environments, Queensland University of Technology, Brisbane, Australia
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria 3052, Australia.
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22
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Bachmann M, Li W, Edwards MJ, Ahmad SA, Patel S, Szabo I, Gulbins E. Voltage-Gated Potassium Channels as Regulators of Cell Death. Front Cell Dev Biol 2020; 8:611853. [PMID: 33381507 PMCID: PMC7767978 DOI: 10.3389/fcell.2020.611853] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022] Open
Abstract
Ion channels allow the flux of specific ions across biological membranes, thereby determining ion homeostasis within the cells. Voltage-gated potassium-selective ion channels crucially contribute to the setting of the plasma membrane potential, to volume regulation and to the physiologically relevant modulation of intracellular potassium concentration. In turn, these factors affect cell cycle progression, proliferation and apoptosis. The present review summarizes our current knowledge about the involvement of various voltage-gated channels of the Kv family in the above processes and discusses the possibility of their pharmacological targeting in the context of cancer with special emphasis on Kv1.1, Kv1.3, Kv1.5, Kv2.1, Kv10.1, and Kv11.1.
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Affiliation(s)
- Magdalena Bachmann
- Department of Biology, University of Padova, Padua, Italy.,Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Weiwei Li
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Michael J Edwards
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Syed A Ahmad
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Sameer Patel
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padua, Italy.,Consiglio Nazionale delle Ricerche Institute of Neuroscience, Padua, Italy
| | - Erich Gulbins
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States.,Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany
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23
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Fan C, Yang X, Wang WW, Wang J, Li W, Guo M, Huang S, Wang Z, Liu K. Role of Kv1.3 Channels in Platelet Functions and Thrombus Formation. Arterioscler Thromb Vasc Biol 2020; 40:2360-2375. [PMID: 32787516 DOI: 10.1161/atvbaha.120.314278] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective:
Platelet activation by stimulatory factors leads to an increase in intracellular calcium concentration ([Ca
2+
]
i
), which is essential for almost all platelet functions. Modulation of Ca
2+
influx and [Ca
2+
]
i
in platelets has been emerging as a possible strategy for preventing and treating platelet-dependent thrombosis. Voltage-gated potassium 1.3 channels (Kv1.3) are highly expressed in platelets and able to regulate agonist-evoked [Ca
2+
]
i
increase. However, the role of Kv1.3 channels in regulating platelet functions and thrombosis has not yet been elucidated. In addition, it is difficult to obtain a specific blocker for this channel, since Kv1.3 shares identical drug-binding sites with other K
+
channels. Here, we investigate whether specific blockade of Kv1.3 channels by monoclonal antibodies affects platelet functions and thrombosis.
Approach and Results:
In this study, we produced the anti-Kv1.3 monoclonal antibody 6E12#15, which could specifically recognize both human and mouse Kv1.3 proteins and sufficiently block Kv1.3 channel currents. We found Kv1.3 blockade by 6E12#15 inhibited platelet aggregation, adhesion, and activation upon agonist stimulation. In vivo treatment with 6E12#15 alleviated thrombus formation in a mesenteric arteriole thrombosis mouse model and protected mice from collagen/epinephrine-induced pulmonary thromboembolism. Furthermore, we observed Kv1.3 regulated platelet functions by modulating Ca
2+
influx and [Ca
2+
]
i
elevation, and that this is mediated in part by P2X
1
. Interestingly,
Kv1.3
−/−
mice showed impaired platelet aggregation while displayed no abnormalities in in vivo thrombus formation. This phenomenon was related to more megakaryocytes and platelets produced in
Kv1.3
−/−
mice compared with wild-type mice.
Conclusions:
We showed specific inhibition of Kv1.3 by the novel monoclonal antibody 6E12#15 suppressed platelet functions and platelet-dependent thrombosis through modulating platelet [Ca
2+
]
i
elevation. These results indicate that Kv1.3 could act as a promising therapeutic target for antiplatelet therapies.
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Affiliation(s)
- Cheng Fan
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (C.F., M.G., S.H., Z.W.)
| | - Xiaofang Yang
- Center for Cardiac Intensive Care, Beijing Anzhen Hospital, Capital Medical University, China (X.Y.)
| | | | - Jue Wang
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (J.W.)
| | - Wenzhu Li
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston (W.L.)
| | - Mengyuan Guo
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (C.F., M.G., S.H., Z.W.)
| | - Shiyuan Huang
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (C.F., M.G., S.H., Z.W.)
| | - Zhaohui Wang
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (C.F., M.G., S.H., Z.W.)
| | - Kun Liu
- Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (K.L.)
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24
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Peruzzo R, Mattarei A, Azzolini M, Becker-Flegler KA, Romio M, Rigoni G, Carrer A, Biasutto L, Parrasia S, Kadow S, Managò A, Urbani A, Rossa A, Semenzato G, Soriano ME, Trentin L, Ahmad S, Edwards M, Gulbins E, Paradisi C, Zoratti M, Leanza L, Szabò I. Insight into the mechanism of cytotoxicity of membrane-permeant psoralenic Kv1.3 channel inhibitors by chemical dissection of a novel member of the family. Redox Biol 2020; 37:101705. [PMID: 33007503 PMCID: PMC7527709 DOI: 10.1016/j.redox.2020.101705] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/14/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023] Open
Abstract
The potassium channel Kv1.3, involved in several important pathologies, is the target of a family of psoralen-based drugs whose mechanism of action is not fully understood. Here we provide evidence for a physical interaction of the mitochondria-located Kv1.3 (mtKv1.3) and Complex I of the respiratory chain and show that this proximity underlies the death-inducing ability of psoralenic Kv1.3 inhibitors. The effects of PAP-1-MHEG (PAP-1, a Kv1.3 inhibitor, with six monomeric ethylene glycol units attached to the phenyl ring of PAP-1), a more soluble novel derivative of PAP-1 and of its various portions on mitochondrial physiology indicate that the psoralenic moiety of PAP-1 bound to mtKv1.3 facilitates the diversion of electrons from Complex I to molecular oxygen. The resulting massive production of toxic Reactive Oxygen Species leads to death of cancer cells expressing Kv1.3. In vivo, PAP-1-MHEG significantly decreased melanoma volume. In summary, PAP-1-MHEG offers insights into the mechanisms of cytotoxicity of this family of compounds and may represent a valuable clinical tool. The mitochondrial channel mitoKv1.3 is a promising pharmacological target. MitoKv1.3 interacts with Complex I of the respiratory chain. Psoralenic inhibitors of Kv1.3 facilitate the diversion of e− from complex I to O2. A novel psoralenic Kv1.3 inhibitor with increased solubility reduces melanoma volume.
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Affiliation(s)
| | - Andrea Mattarei
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Italy
| | | | | | - Matteo Romio
- Department of Chemical Sciences, University of Padua, Italy
| | | | - Andrea Carrer
- Department of Biology, University of Padua, Italy; Department of Biomedical Sciences, University of Padua, Italy
| | - Lucia Biasutto
- Department of Biomedical Sciences, University of Padua, Italy; CNR Institute of Neuroscience, Padua, Italy
| | - Sofia Parrasia
- Department of Biomedical Sciences, University of Padua, Italy
| | - Stephanie Kadow
- Department of Molecular Biology, University of Duisburg-Essen, Germany
| | | | - Andrea Urbani
- Department of Biology, University of Padua, Italy; Department of Biomedical Sciences, University of Padua, Italy
| | - Andrea Rossa
- Department of Chemical Sciences, University of Padua, Italy
| | | | | | | | - Syed Ahmad
- Department of Surgery, Medical School, University of Cincinnati, USA
| | - Michael Edwards
- Department of Surgery, Medical School, University of Cincinnati, USA
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Germany
| | | | - Mario Zoratti
- Department of Biomedical Sciences, University of Padua, Italy; CNR Institute of Neuroscience, Padua, Italy
| | - Luigi Leanza
- Department of Biology, University of Padua, Italy
| | - Ildikò Szabò
- Department of Biology, University of Padua, Italy; CNR Institute of Neuroscience, Padua, Italy.
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25
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Effect of Ultrafine Powderization and Solid Dispersion Formation via Hot-Melt Extrusion on Antioxidant, Anti-Inflammatory, and the Human Kv1.3 Channel Inhibitory Activities of Angelica gigas Nakai. Bioinorg Chem Appl 2020; 2020:7846176. [PMID: 32952541 PMCID: PMC7482008 DOI: 10.1155/2020/7846176] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 08/08/2020] [Indexed: 12/28/2022] Open
Abstract
Angelica gigas Nakai (AGN) was first processed by ultrafine grinding technology and hot-melt extrusion (HME). The potential antioxidant and anti-inflammatory activities of AGN with a different process were compared, and the effect on the human Kv1.3 potassium channel was detected. The process of ultrafine powderization on AGN significantly increased the total phenolic and flavonoid contents, antioxidant activity, and DNA damage protective effect. On the contrary, AGN solid dispersion (AGN-SD) based on Soluplus® showed the highest inhibitory effect on NO production and the human Kv1.3 channel. In addition, AGN-SD inhibited the production of prostaglandin E2 and intracellular reactive oxygen species and the mRNA expression of inducible nitric oxide synthase, cyclooxygenase-2, interleukin 1β, and interleukin 6. Taken together, these results suggest that ultrafine powderization and solid dispersion formation via HME can significantly improve the biological activities of AGN. The results also suggested that ultrafine powderization and HME may be developed and applied in the pharmaceutical industry.
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26
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Clinical Importance of the Human Umbilical Artery Potassium Channels. Cells 2020; 9:cells9091956. [PMID: 32854241 PMCID: PMC7565333 DOI: 10.3390/cells9091956] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023] Open
Abstract
Potassium (K+) channels are usually predominant in the membranes of vascular smooth muscle cells (SMCs). These channels play an important role in regulating the membrane potential and vessel contractility-a role that depends on the vascular bed. Thus, the activity of K+ channels represents one of the main mechanisms regulating the vascular tone in physiological and pathophysiological conditions. Briefly, the activation of K+ channels in SMC leads to hyperpolarization and vasorelaxation, while its inhibition induces depolarization and consequent vascular contraction. Currently, there are four different types of K+ channels described in SMCs: voltage-dependent K+ (KV) channels, calcium-activated K+ (KCa) channels, inward rectifier K+ (Kir) channels, and 2-pore domain K+ (K2P) channels. Due to the fundamental role of K+ channels in excitable cells, these channels are promising therapeutic targets in clinical practice. Therefore, this review discusses the basic properties of the various types of K+ channels, including structure, cellular mechanisms that regulate their activity, and new advances in the development of activators and blockers of these channels. The vascular functions of these channels will be discussed with a focus on vascular SMCs of the human umbilical artery. Then, the clinical importance of K+ channels in the treatment and prevention of cardiovascular diseases during pregnancy, such as gestational hypertension and preeclampsia, will be explored.
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27
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Tajti G, Wai DCC, Panyi G, Norton RS. The voltage-gated potassium channel K V1.3 as a therapeutic target for venom-derived peptides. Biochem Pharmacol 2020; 181:114146. [PMID: 32653588 DOI: 10.1016/j.bcp.2020.114146] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/05/2020] [Accepted: 07/07/2020] [Indexed: 02/07/2023]
Abstract
The voltage-gated potassium channel KV1.3 is a well-established therapeutic target for a range of autoimmune diseases, in addition to being the site of action of many venom-derived peptides. Numerous studies have documented the efficacy of venom peptides that target KV1.3, in particular from sea anemones and scorpions, in animal models of autoimmune diseases such as rheumatoid arthritis, psoriasis and multiple sclerosis. Moreover, an analogue of the sea anemone peptide ShK (known as dalazatide) has successfully completed Phase 1 clinical trials in mild-to-moderate plaque psoriasis. In this article we consider other potential therapeutic applications of inhibitors of KV1.3, including in inflammatory bowel disease and neuroinflammatory conditions such as Alzheimer's and Parkinson's diseases, as well as fibrotic diseases. We also summarise strategies for facilitating the entry of peptides to the central nervous system, given that this will be a pre-requisite for the treatment of most neuroinflammatory diseases. Venom-derived peptides that have been reported recently to target KV1.3 are also described. The increasing number of autoimmune and other conditions in which KV1.3 is upregulated and is therefore a potential therapeutic target, combined with the fact that many venom-derived peptides are potent inhibitors of KV1.3, suggests that venoms are likely to continue to serve as a rich source of new pharmacological tools and therapeutic leads targeting this channel.
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Affiliation(s)
- Gabor Tajti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Dorothy C C Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary.
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, VIC 3052, Australia.
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28
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Djokic V, Jankovic S, Labudovic-Borovic M, Rakocevic J, Stanisic J, Rajkovic J, Novakovic R, Kostic M, Djuric M, Gostimirovic M, Gojkovic-Bukarica L. Pregnancy-induced hypertension decreases K v1.3 potassium channel expression and function in human umbilical vein smooth muscle. Eur J Pharmacol 2020; 882:173281. [PMID: 32562800 DOI: 10.1016/j.ejphar.2020.173281] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 10/24/2022]
Abstract
Voltage-gated potassium (Kv) channels are the largest superfamily of potassium (K) channels. A variety of Kv channels are expressed in the vascular smooth muscle cells (SMC). Studies have shown that gestational diabetes mellitus (GDM) and pregnancy-induced hypertension (PIH) cause various changes in the human umbilical vein (HUV). Recently, we have shown that 4-AP, a nonspecific Kv1-4 channel inhibitor, significantly decreases vasorelaxation induced by K channel opener pinacidil in vascular SMCs of the HUVs from normal pregnancies, but not in GDM and PIH. The goal of this study was to provide more detailed insight in the Kv channel subtypes involved in pinacidil-induced vasodilation of HUVs, as well as to investigate potential alterations of their function and expression during GDM and PIH. Margatoxin, a specific blocker of Kv1.2 and Kv1.3 channels, significantly antagonized pinacidil-induced vasorelaxation in normal pregnancy, while in HUVs from GDM and PIH that was not the case, indicating damage of Kv1.2 and Kv1.3 channel function. Immunohistochemistry and Western blot revealed similar expression of Kv1.2 channels in all groups. The expression of Kv1.3 subunit was significantly decreased in PIH, while it remained unchanged in GDM compared to normal pregnancy. Phrixotoxin, specific blocker of Kv4.2 and Kv4.3 channels, did not antagonize response to pinacidil in any of the groups. The major novel findings show that margatoxin antagonized pinacidil-induced relaxation in normal pregnancy, but not in GDM and PIH. Decreased expression of Kv1.3 channels in HUV during PIH may be important pathophysiological mechanism contributing to an increased risk of adverse pregnancy outcomes.
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Affiliation(s)
- Vladimir Djokic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia.
| | - Svetlana Jankovic
- Department of Obstetrics and Gynecology "Narodni Front", Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Milica Labudovic-Borovic
- Institute of Histology and Embryology "Aleksandar Dj. Kostic", Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Jelena Rakocevic
- Institute of Histology and Embryology "Aleksandar Dj. Kostic", Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Jelena Stanisic
- Vinca Institute of Nuclear Sciences, 11000, Belgrade, Serbia
| | - Jovana Rajkovic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Radmila Novakovic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Milan Kostic
- Vinca Institute of Nuclear Sciences, 11000, Belgrade, Serbia
| | - Milos Djuric
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Milos Gostimirovic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Ljiljana Gojkovic-Bukarica
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
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29
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Scorpion Toxins and Ion Channels: Potential Applications in Cancer Therapy. Toxins (Basel) 2020; 12:toxins12050326. [PMID: 32429050 PMCID: PMC7290751 DOI: 10.3390/toxins12050326] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 12/24/2022] Open
Abstract
Apoptosis, a genetically directed process of cell death, has been studied for many years, and the biochemical mechanisms that surround it are well known and described. There are at least three pathways by which apoptosis occurs, and each pathway depends on extra or intracellular processes for activation. Apoptosis is a vital process, but disturbances in proliferation and cell death rates can lead to the development of diseases like cancer. Several compounds, isolated from scorpion venoms, exhibit inhibitory effects on different cancer cells. Indeed, some of these compounds can differentiate between healthy and cancer cells within the same tissue. During the carcinogenic process, morphological, biochemical, and biological changes occur that enable these compounds to modulate cancer but not healthy cells. This review highlights cancer cell features that enable modulation by scorpion neurotoxins. The properties of the isolated scorpion neurotoxins in cancer cells and the potential uses of these compounds as alternative treatments for cancer are discussed.
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30
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Wu B, Liu JD, Bian E, Hu W, Huang C, Meng X, Zhang L, Lv X, Li J. Blockage of Kv1.3 regulates macrophage migration in acute liver injury by targeting δ-catenin through RhoA signaling. Int J Biol Sci 2020; 16:671-681. [PMID: 32025214 PMCID: PMC6990916 DOI: 10.7150/ijbs.38950] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/04/2019] [Indexed: 11/05/2022] Open
Abstract
Background: Activation of macrophages and infiltration are key events in acute liver injury (ALI). Kv1.3 plays an important role in regulating immunologic functions of macrophages and is extensively recognized as a potential ion channel for immunological diseases. Objective: We hypothesized that blockage of Kv1.3 may influence ALI by inhibiting macrophages infiltration in damaged liver tissues. Methods: Margatoxin was administered into the peritoneal cavity of ALI mice. The impact of this treatment on ALI and macrophage migration in vivo and in vitro was determined using immunohistochemistry, transwell migration, and wound healing assays. Results: MgTX treatment alleviated ALI in mice, as evidenced by reduced macrophage infiltration in liver tissues and lower serum levels of liver ALT and AST. RNA-seq profiling analysis showed that the most obvious change by MgTX treatment was downregulation of δ-catenin, a protein known to be associated with macrophage migration. The effect of MgTX on macrophage migration and involvement of δ-catenin was confirmed by transwell and wound healing assays. Overexpression of δ-catenin in RAW264.7 cells promoted migration, an event that was suppressed upon silencing of δ-catenin. Mechanistically, the expression of RhoA was regulated by the overexpression or knockdown of δ-catenin. Conclusion: These findings suggest a role for blockage of Kv1.3 channel in macrophage migration and reveal a new target in the treatment of ALI.
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Affiliation(s)
- Baoming Wu
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China.,The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.,Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China.,Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China
| | - Jun-da Liu
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China.,The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.,Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China.,Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China.,The first affiliated hospital of Anhui medical university, Hefei 230032, China
| | - Erbao Bian
- The second affiliated hospital of Anhui medical university, Hefei 230032, China
| | - Wei Hu
- The second affiliated hospital of Anhui medical university, Hefei 230032, China
| | - Cheng Huang
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China.,The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.,Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China.,Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China
| | - Xiaoming Meng
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China.,The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.,Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China.,Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China
| | - Lei Zhang
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China.,The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.,Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China.,Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China
| | - Xiongwen Lv
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China.,The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.,Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China.,Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China
| | - Jun Li
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China.,The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.,Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China.,Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China
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31
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Wang X, Li G, Guo J, Zhang Z, Zhang S, Zhu Y, Cheng J, Yu L, Ji Y, Tao J. Kv1.3 Channel as a Key Therapeutic Target for Neuroinflammatory Diseases: State of the Art and Beyond. Front Neurosci 2020; 13:1393. [PMID: 31992966 PMCID: PMC6971160 DOI: 10.3389/fnins.2019.01393] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 12/10/2019] [Indexed: 12/26/2022] Open
Abstract
It remains a challenge for the effective treatment of neuroinflammatory disease, including multiple sclerosis (MS), stroke, epilepsy, and Alzheimer’s and Parkinson’s disease. The voltage-gated potassium Kv1.3 channel is of interest, which is considered as a novel therapeutic target for treating neuroinflammatory disorders due to its crucial role in subsets of T lymphocytes as well as microglial cells. Toxic animals, such as sea anemones, scorpions, spiders, snakes, and cone snails, can produce a variety of toxins that act on the Kv1.3 channel. The Stichodactyla helianthus K+ channel blocking toxin (ShK) from the sea anemone S. helianthus is proved as a classical blocker of Kv1.3. One of the synthetic analogs ShK-186, being developed as a therapeutic for autoimmune diseases, has successfully completed first-in-man Phase 1 trials. In addition to addressing the recent progress on the studies underlying the pharmacological characterizations of ShK on MS, the review will also explore the possibility for clinical treatment of ShK-like Kv1.3 blocking polypeptides on other neuroinflammatory diseases.
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Affiliation(s)
- Xiaoli Wang
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Guoyi Li
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jingkang Guo
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Zhiping Zhang
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Shuzhang Zhang
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China
| | - Yudan Zhu
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jiwei Cheng
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lu Yu
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yonghua Ji
- Institute of Biomembrane and Biopharmaceutics, Shanghai University, Shanghai, China,Xinhua Translational Institute for Cancer Pain, Shanghai, China
| | - Jie Tao
- Department of Neurology and Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Putuo Clinical Medical School, Anhui Medical University, Shanghai, China
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Bajaj S, Han J. Venom-Derived Peptide Modulators of Cation-Selective Channels: Friend, Foe or Frenemy. Front Pharmacol 2019; 10:58. [PMID: 30863305 PMCID: PMC6399158 DOI: 10.3389/fphar.2019.00058] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 01/18/2019] [Indexed: 01/31/2023] Open
Abstract
Ion channels play a key role in our body to regulate homeostasis and conduct electrical signals. With the help of advances in structural biology, as well as the discovery of numerous channel modulators derived from animal toxins, we are moving toward a better understanding of the function and mode of action of ion channels. Their ubiquitous tissue distribution and the physiological relevancies of their opening and closing suggest that cation channels are particularly attractive drug targets, and years of research has revealed a variety of natural toxins that bind to these channels and alter their function. In this review, we provide an introductory overview of the major cation ion channels: potassium channels, sodium channels and calcium channels, describe their venom-derived peptide modulators, and how these peptides provide great research and therapeutic value to both basic and translational medical research.
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Affiliation(s)
- Saumya Bajaj
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Jingyao Han
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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Nagy É, Mocsár G, Sebestyén V, Volkó J, Papp F, Tóth K, Damjanovich S, Panyi G, Waldmann TA, Bodnár A, Vámosi G. Membrane Potential Distinctly Modulates Mobility and Signaling of IL-2 and IL-15 Receptors in T Cells. Biophys J 2018; 114:2473-2482. [PMID: 29754714 PMCID: PMC6129476 DOI: 10.1016/j.bpj.2018.04.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/21/2018] [Accepted: 04/23/2018] [Indexed: 12/11/2022] Open
Abstract
The high electric field across the plasma membrane might influence the conformation and behavior of transmembrane proteins that have uneven charge distributions in or near their transmembrane regions. Membrane depolarization of T cells occurs in the tumor microenvironment and in inflamed tissues because of K+ release from necrotic cells and hypoxia affecting the expression of K+ channels. However, little attention has been given to the effect of membrane potential (MP) changes on membrane receptor function. Therefore, we studied the influence of membrane de- and hyperpolarization on the biophysical properties and signaling of interleukin-2 (IL-2) and interleukin-15 (IL-15) receptors, which play important roles in T cell function. We investigated the mobility, clustering, and signaling of these receptors and major histocompatibility complex (MHC) I/II glycoproteins forming coclusters in lipid rafts of T cells. Depolarization by high K+ buffer or K+ channel blockers resulted in a decrease in the mobility of IL-2Rα and MHC glycoproteins, as shown by fluorescence correlation spectroscopy, whereas hyperpolarization by the K+ ionophore valinomycin increased their mobility. Contrary to this, the mobility of IL-15Rα decreased upon both de- and hyperpolarization. These changes in protein mobility are not due to an alteration of membrane fluidity, as evidenced by fluorescence anisotropy measurements. Förster resonance energy transfer measurements showed that most homo- or heteroassociations of IL-2R, IL-15R, and MHC I did not change considerably, either. MP changes modulated signaling by the two cytokines in distinct ways: depolarization caused a significant increase in the IL-2-induced phosphorylation of signal transducer and activator of transcription 5, whereas hyperpolarization evoked a decrease only in the IL-15-induced signal. Our data imply that the MP may be an important modulator of interleukin receptor signaling and dynamics. Enhanced IL-2 signaling in depolarized Treg cells highly expressing IL-2R may contribute to suppression of antitumor immune surveillance.
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Affiliation(s)
- Éva Nagy
- Department of Biophysics and Cell Biology, Faculty of Medicine
| | - Gábor Mocsár
- Department of Biophysics and Cell Biology, Faculty of Medicine
| | | | - Julianna Volkó
- Department of Biophysics and Cell Biology, Faculty of Medicine
| | - Ferenc Papp
- Department of Biophysics and Cell Biology, Faculty of Medicine; MTA-DE- NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Debrecen, Hungary
| | - Katalin Tóth
- Division Biophysics of Macromolecules, German Cancer Research Center, Heidelberg, Germany
| | | | - György Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine; MTA-DE- NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Debrecen, Hungary
| | - Thomas A Waldmann
- Lymphoid Malignancies Branch, National Institutes of Health, Bethesda, Maryland
| | - Andrea Bodnár
- Department of Biophysics and Cell Biology, Faculty of Medicine
| | - György Vámosi
- Department of Biophysics and Cell Biology, Faculty of Medicine.
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Valle-Reyes S, Valencia-Cruz G, Liñan-Rico L, Pottosin I, Dobrovinskaya O. Differential Activity of Voltage- and Ca 2+-Dependent Potassium Channels in Leukemic T Cell Lines: Jurkat Cells Represent an Exceptional Case. Front Physiol 2018; 9:499. [PMID: 29867547 PMCID: PMC5954129 DOI: 10.3389/fphys.2018.00499] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 04/18/2018] [Indexed: 12/17/2022] Open
Abstract
Activation of resting T cells relies on sustained Ca2+ influx across the plasma membrane, which in turn depends on the functional expression of potassium channels, whose activity repolarizes the membrane potential. Depending on the T-cells subset, upon activation the expression of Ca2+- or voltage-activated K+ channels, KCa or Kv, is up-regulated. In this study, by means of patch-clamp technique in the whole cell mode, we have studied in detail the characteristics of Kv and KCa currents in resting and activated human T cells, the only well explored human T-leukemic cell line Jurkat, and two additional human leukemic T cell lines, CEM and MOLT-3. Voltage dependence of activation and inactivation of Kv1.3 current were shifted up to by 15 mV to more negative potentials upon a prolonged incubation in the whole cell mode and displayed little difference at a stable state in all cell lines but CEM, where the activation curve was biphasic, with a high and low potential components. In Jurkat, KCa currents were dominated by apamine-sensitive KCa2.2 channels, whereas only KCa3.1 current was detected in healthy T and leukemic CEM and MOLT-3 cells. Despite a high proliferation potential of Jurkat cells, Kv and KCa currents were unexpectedly small, more than 10-fold lesser as compared to activated healthy human T cells, CEM and MOLT-3, which displayed characteristic Kv1.3high:KCa3.1high phenotype. Our results suggest that Jurkat cells represent perhaps a singular case and call for more extensive studies on primary leukemic T cell lines as well as a verification of the therapeutic potential of specific KCa3.1 blockers to combat acute lymphoblastic T leukemias.
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Affiliation(s)
- Salvador Valle-Reyes
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | - Georgina Valencia-Cruz
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | - Liliana Liñan-Rico
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | - Igor Pottosin
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | - Oxana Dobrovinskaya
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
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Aissaoui D, Mlayah-Bellalouna S, Jebali J, Abdelkafi-Koubaa Z, Souid S, Moslah W, Othman H, Luis J, ElAyeb M, Marrakchi N, Essafi-Benkhadir K, Srairi-Abid N. Functional role of Kv1.1 and Kv1.3 channels in the neoplastic progression steps of three cancer cell lines, elucidated by scorpion peptides. Int J Biol Macromol 2018; 111:1146-1155. [DOI: 10.1016/j.ijbiomac.2018.01.144] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/19/2018] [Accepted: 01/20/2018] [Indexed: 12/11/2022]
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Voros O, Szilagyi O, Balajthy A, Somodi S, Panyi G, Hajdu P. The C-terminal HRET sequence of Kv1.3 regulates gating rather than targeting of Kv1.3 to the plasma membrane. Sci Rep 2018; 8:5937. [PMID: 29650988 PMCID: PMC5897520 DOI: 10.1038/s41598-018-24159-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 03/08/2018] [Indexed: 12/13/2022] Open
Abstract
Kv1.3 channels are expressed in several cell types including immune cells, such as T lymphocytes. The targeting of Kv1.3 to the plasma membrane is essential for T cell clonal expansion and assumed to be guided by the C-terminus of the channel. Using two point mutants of Kv1.3 with remarkably different features compared to the wild-type Kv1.3 (A413V and H399K having fast inactivation kinetics and tetraethylammonium-insensitivity, respectively) we showed that both Kv1.3 channel variants target to the membrane when the C-terminus was truncated right after the conserved HRET sequence and produce currents identical to those with a full-length C-terminus. The truncation before the HRET sequence (NOHRET channels) resulted in reduced membrane-targeting but non-functional phenotypes. NOHRET channels did not display gating currents, and coexpression with wild-type Kv1.3 did not rescue the NOHRET-A413V phenotype, no heteromeric current was observed. Interestingly, mutants of wild-type Kv1.3 lacking HRET(E) (deletion) or substituted with five alanines for the HRET(E) motif expressed current indistinguishable from the wild-type. These results demonstrate that the C-terminal region of Kv1.3 immediately proximal to the S6 helix is required for the activation gating and conduction, whereas the presence of the distal region of the C-terminus is not exclusively required for trafficking of Kv1.3 to the plasma membrane.
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Affiliation(s)
- Orsolya Voros
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 400, 1 Egyetem sq., Debrecen, 4032, Hungary
| | - Orsolya Szilagyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 400, 1 Egyetem sq., Debrecen, 4032, Hungary
| | - András Balajthy
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, 400, 1 Egyetem sq., Debrecen, 4032, Hungary
| | - Sándor Somodi
- Department of Internal Medicine, Faculty of Medicine, University of Debrecen, 400, 1 Egyetem sq., Debrecen, 4032, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 1 Egyetem sq., 4032, Hungary. MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, 400, Debrecen, Hungary
| | - Péter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 400, 1 Egyetem sq., Debrecen, 4032, Hungary. .,Department of Biophysics and Cell Biology, Faculty of Dentistry, University of Debrecen, 400, 1 Egyetem sq., Debrecen, 4032, Hungary.
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Guan D, Pathak D, Foehring RC. Functional roles of Kv1-mediated currents in genetically identified subtypes of pyramidal neurons in layer 5 of mouse somatosensory cortex. J Neurophysiol 2018; 120:394-408. [PMID: 29641306 DOI: 10.1152/jn.00691.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We used voltage-clamp recordings from somatic outside-out macropatches to determine the amplitude and biophysical properties of putative Kv1-mediated currents in layer 5 pyramidal neurons (PNs) from mice expressing EGFP under the control of promoters for etv1 or glt. We then used whole cell current-clamp recordings and Kv1-specific peptide blockers to test the hypothesis that Kv1 channels differentially regulate action potential (AP) voltage threshold, repolarization rate, and width as well as rheobase and repetitive firing in these two PN types. We found that Kv1-mediated currents make up a similar percentage of whole cell K+ current in both cell types, and only minor biophysical differences were observed between PN types or between currents sensitive to different Kv1 blockers. Putative Kv1 currents contributed to AP voltage threshold in both PN types, but AP width and rate of repolarization were only affected in etv1 PNs. Kv1 currents regulate rheobase, delay to the first AP, and firing rate similarly in both cell types, but the frequency-current slope was much more sensitive to Kv1 block in etv1 PNs. In both cell types, Kv1 block shifted the current required to elicit an onset doublet of action potentials to lower currents. Spike frequency adaptation was also affected differently by Kv1 block in the two PN types. Thus, despite similar expression levels and minimal differences in biophysical properties, Kv1 channels differentially regulate APs and repetitive firing in etv1 and glt PNs. This may reflect differences in subcellular localization of channel subtypes or differences in the other K+ channels expressed. NEW & NOTEWORTHY In two types of genetically identified layer 5 pyramidal neurons, α-dendrotoxin blocked approximately all of the putative Kv1 current (on average). We used outside-out macropatches and whole cell recordings at 33°C to show that despite similar expression levels and minimal differences in biophysical properties, Kv1 channels differentially regulate action potentials and repetitive firing in etv1 and glt pyramidal neurons. This may reflect differences in subcellular localization of channel subtypes or differences in the other K+ channels expressed.
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Affiliation(s)
- Dongxu Guan
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Dhruba Pathak
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Robert C Foehring
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center , Memphis, Tennessee
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Prentis PJ, Pavasovic A, Norton RS. Sea Anemones: Quiet Achievers in the Field of Peptide Toxins. Toxins (Basel) 2018; 10:toxins10010036. [PMID: 29316700 PMCID: PMC5793123 DOI: 10.3390/toxins10010036] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/04/2018] [Accepted: 01/04/2018] [Indexed: 01/09/2023] Open
Abstract
Sea anemones have been understudied as a source of peptide and protein toxins, with relatively few examined as a source of new pharmacological tools or therapeutic leads. This is surprising given the success of some anemone peptides that have been tested, such as the potassium channel blocker from Stichodactyla helianthus known as ShK. An analogue of this peptide, ShK-186, which is now known as dalazatide, has successfully completed Phase 1 clinical trials and is about to enter Phase 2 trials for the treatment of autoimmune diseases. One of the impediments to the exploitation of sea anemone toxins in the pharmaceutical industry has been the difficulty associated with their high-throughput discovery and isolation. Recent developments in multiple ‘omic’ technologies, including genomics, transcriptomics and proteomics, coupled with advanced bioinformatics, have opened the way for large-scale discovery of novel sea anemone toxins from a range of species. Many of these toxins will be useful pharmacological tools and some will hopefully prove to be valuable therapeutic leads.
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Affiliation(s)
- Peter J Prentis
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia.
- Institute of Future Environments, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia.
| | - Ana Pavasovic
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia.
- Faculty of Health, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia.
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
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Renauld S, Cortes S, Bersch B, Henry X, De Waard M, Schaack B. Functional reconstitution of cell-free synthesized purified Kv channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2373-2380. [DOI: 10.1016/j.bbamem.2017.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/29/2017] [Accepted: 09/05/2017] [Indexed: 12/11/2022]
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Jimenez R, Ikonomopoulou MP, Lopez JA, Miles JJ. Immune drug discovery from venoms. Toxicon 2017; 141:18-24. [PMID: 29170055 DOI: 10.1016/j.toxicon.2017.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 11/14/2017] [Accepted: 11/18/2017] [Indexed: 01/22/2023]
Abstract
This review catalogues recent advances in knowledge on venoms as standalone therapeutic agents or as blueprints for drug design, with an emphasis on venom-derived compounds that affects the immune system. We discuss venoms and venom-derived compounds that affect total immune cell numbers, immune cell proliferation, immune cell migration, immune cell phenotype and cytokine secretion. Identifying novel compounds that 'tune' the system, up-regulating the immune response during infectious disease and cancer and down-regulating the immune response during autoimmunity, will greatly expand the tool kit of human immunotherapeutics. Targeting these pathways may also open therapeutic options that alleviate symptoms of envenomation. Finally, combining recent advances in venomics with progress in low cost, high-throughput screening platforms will no doubt yield hundreds of prototype immune modulating compounds in the coming years.
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Affiliation(s)
- Rocio Jimenez
- Griffith University, School of Natural Sciences, Brisbane, Queensland, Australia; QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Maria P Ikonomopoulou
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia; School of Medicine, The University of Queensland, Brisbane, Australia; Madrid Institute for Advanced Studies (IMDEA) in Food, CEI UAM+CSIC, Madrid, Spain
| | - J Alejandro Lopez
- Griffith University, School of Natural Sciences, Brisbane, Queensland, Australia; QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - John J Miles
- Griffith University, School of Natural Sciences, Brisbane, Queensland, Australia; QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia; School of Medicine, The University of Queensland, Brisbane, Australia; Centre for Biodiscovery and Molecular Development of Therapeutics, AITHM, James Cook University, Cairns, Queensland, Australia; Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom.
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41
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Yuan S, Gao B, Zhu S. Molecular Dynamics Simulation Reveals Specific Interaction Sites between Scorpion Toxins and K v1.2 Channel: Implications for Design of Highly Selective Drugs. Toxins (Basel) 2017; 9:toxins9110354. [PMID: 29104247 PMCID: PMC5705969 DOI: 10.3390/toxins9110354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/15/2017] [Accepted: 10/19/2017] [Indexed: 01/06/2023] Open
Abstract
The Kv1.2 channel plays an important role in the maintenance of resting membrane potential and the regulation of the cellular excitability of neurons, whose silencing or mutations can elicit neuropathic pain or neurological diseases (e.g., epilepsy and ataxia). Scorpion venom contains a variety of peptide toxins targeting the pore region of this channel. Despite a large amount of structural and functional data currently available, their detailed interaction modes are poorly understood. In this work, we choose four Kv1.2-targeted scorpion toxins (Margatoxin, Agitoxin-2, OsK-1, and Mesomartoxin) to construct their complexes with Kv1.2 based on the experimental structure of ChTx-Kv1.2. Molecular dynamics simulation of these complexes lead to the identification of hydrophobic patches, hydrogen-bonds, and salt bridges as three essential forces mediating the interactions between this channel and the toxins, in which four Kv1.2-specific interacting amino acids (D353, Q358, V381, and T383) are identified for the first time. This discovery might help design highly selective Kv1.2-channel inhibitors by altering amino acids of these toxins binding to the four channel residues. Finally, our results provide new evidence in favor of an induced fit model between scorpion toxins and K+ channel interactions.
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Affiliation(s)
- Shouli Yuan
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Bin Gao
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Shunyi Zhu
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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42
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Lam D, Lively S, Schlichter LC. Responses of rat and mouse primary microglia to pro- and anti-inflammatory stimuli: molecular profiles, K + channels and migration. J Neuroinflammation 2017; 14:166. [PMID: 28830445 PMCID: PMC5567442 DOI: 10.1186/s12974-017-0941-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/13/2017] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Acute CNS damage is commonly studied using rat and mouse models, but increasingly, molecular analysis is finding species differences that might affect the ability to translate findings to humans. Microglia can undergo complex molecular and functional changes, often studied by in vitro responses to discrete activating stimuli. There is considerable evidence that pro-inflammatory (M1) activation can exacerbate tissue damage, while anti-inflammatory (M2) states help resolve inflammation and promote tissue repair. However, in assessing potential therapeutic targets for controlling inflammation, it is crucial to determine whether rat and mouse microglia respond the same. METHODS Primary microglia from Sprague-Dawley rats and C57BL/6 mice were cultured, then stimulated with interferon-γ + tumor necrosis factor-α (I + T; M1 activation), interleukin (IL)-4 (M2a, alternative activation), or IL-10 (M2c, acquired deactivation). To profile their activation responses, NanoString was used to monitor messenger RNA (mRNA) expression of numerous pro- and anti-inflammatory mediators, microglial markers, immunomodulators, and other molecules. Western analysis was used to measure selected proteins. Two potential targets for controlling inflammation-inward- and outward-rectifier K+ channels (Kir2.1, Kv1.3)-were examined (mRNA, currents) and specific channel blockers were applied to determine their contributions to microglial migration in the different activation states. RESULTS Pro-inflammatory molecules increased after I + T treatment but there were several qualitative and quantitative differences between the species (e.g., iNOS and nitric oxide, COX-2). Several molecules commonly associated with an M2a state differed between species or they were induced in additional activation states (e.g., CD206, ARG1). Resting levels and/or responses of several microglial markers (Iba1, CD11b, CD68) differed with the activation state, species, or both. Transcripts for several Kir2 and Kv1 family members were detected in both species. However, the current amplitudes (mainly Kir2.1 and Kv1.3) depended on activation state and species. Treatment-induced changes in morphology and migratory capacity were similar between the species (migration reduced by I + T, increased by IL-4 or IL-10). In both species, Kir2.1 block reduced migration and Kv1.3 block increased it, regardless of activation state; thus, these channels might affect microglial migration to damage sites. CONCLUSIONS Caution is recommended in generalizing molecular and functional responses of microglia to activating stimuli between species.
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Affiliation(s)
- Doris Lam
- Genes and Development Division, Krembil Research Institute, University Health Network, Krembil Discovery Tower, Room 7KD417, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Starlee Lively
- Genes and Development Division, Krembil Research Institute, University Health Network, Krembil Discovery Tower, Room 7KD417, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada
| | - Lyanne C Schlichter
- Genes and Development Division, Krembil Research Institute, University Health Network, Krembil Discovery Tower, Room 7KD417, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada. .,Department of Physiology, University of Toronto, Toronto, ON, Canada.
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Olamendi-Portugal T, Csoti A, Jimenez-Vargas J, Gomez-Lagunas F, Panyi G, Possani L. Pi5 and Pi6, two undescribed peptides from the venom of the scorpion Pandinus imperator and their effects on K + -channels. Toxicon 2017; 133:136-144. [DOI: 10.1016/j.toxicon.2017.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/06/2017] [Accepted: 05/09/2017] [Indexed: 01/15/2023]
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44
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Voos P, Yazar M, Lautenschläger R, Rauh O, Moroni A, Thiel G. The small neurotoxin apamin blocks not only small conductance Ca 2+ activated K + channels (SK type) but also the voltage dependent Kv1.3 channel. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:517-523. [PMID: 28108814 DOI: 10.1007/s00249-016-1196-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/12/2016] [Accepted: 12/30/2016] [Indexed: 11/29/2022]
Abstract
Apamin is frequently used as a specific blocker of small-conductance Ca2+-activated (SK type) K+ channels. Here we show that the small neurotoxin is not as specific as anticipated. It is also a high-affinity inhibitor with an IC50 of 13 nM of the Kv1.3 channel; it blocks the latter with potency similar to the Kv1.3 blocker PAP-1. Since SK type channels and Kv1.3 channels are frequently coexpressed in different tissues such as cells of the immune system, apamin must be used with caution as a pharmacological tool.
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Affiliation(s)
- Patrick Voos
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - Mehtap Yazar
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - René Lautenschläger
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - Oliver Rauh
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - Anna Moroni
- Department of Biology and CNR IBF-Mi, Università degli Studi di Milano, Milan, Italy
| | - Gerhard Thiel
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany.
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Schwartz AB, Kapur A, Wang W, Huang Z, Fardone E, Palui G, Mattoussi H, Fadool DA. Margatoxin-bound quantum dots as a novel inhibitor of the voltage-gated ion channel Kv1.3. J Neurochem 2016; 140:404-420. [PMID: 27861889 DOI: 10.1111/jnc.13891] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 10/24/2016] [Accepted: 10/31/2016] [Indexed: 01/01/2023]
Abstract
Venom-derived ion channel inhibitors have strong channel selectivity, potency, and stability; however, tracking delivery to their target can be challenging. Herein, we utilized luminescent quantum dots (QDs) conjugated to margatoxin (MgTx) as a traceable vehicle to target a voltage-dependent potassium channel, Kv1.3, which has a select distribution and well-characterized role in immunity, glucose metabolism, and sensory ability. We screened both unconjugated (MgTx) and conjugated MgTx (QD-MgTx) for their ability to inhibit Shaker channels Kv1.1 to Kv1.7 using patch-clamp electrophysiology in HEK293 cells. Our data indicate that MgTx inhibits 79% of the outward current in Kv1.3-transfected cells and that the QD-MgTx conjugate is able to achieve a similar level of block, albeit a slightly reduced efficacy (66%) and at a slower time course (50% block by 10.9 ± 1.1 min, MgTx; vs. 15.3 ± 1.2 min, QD-MgTx). Like the unbound peptide, the QD-MgTx conjugate inhibits both Kv1.3 and Kv1.2 at a 1 nM concentration, whereas it does not inhibit other screened Shaker channels. We tested the ability of QD-MgTx to inhibit native Kv1.3 expressed in the mouse olfactory bulb (OB). In brain slices of the OB, the conjugate acted similarly to MgTx to inhibit Kv1.3, causing an increased action potential firing frequency attributed to decreased intraburst duration rather than interspike interval. Our data demonstrate a retention of known biophysical properties associated with block of the vestibule of Kv1.3 by QD-MgTx conjugate compared to that of MgTx, inferring QDs could provide a useful tool to deliver ion channel inhibitors to targeted tissues in vivo.
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Affiliation(s)
- Austin B Schwartz
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
| | - Anshika Kapur
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Wentao Wang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Zhenbo Huang
- Program in Neuroscience, Florida State University, Tallahassee, Florida, USA
| | - Erminia Fardone
- Program in Neuroscience, Florida State University, Tallahassee, Florida, USA.,Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Goutam Palui
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Hedi Mattoussi
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Debra Ann Fadool
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA.,Program in Neuroscience, Florida State University, Tallahassee, Florida, USA.,Department of Biological Science, Florida State University, Tallahassee, Florida, USA
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Housley DM, Housley GD, Liddell MJ, Jennings EA. Scorpion toxin peptide action at the ion channel subunit level. Neuropharmacology 2016; 127:46-78. [PMID: 27729239 DOI: 10.1016/j.neuropharm.2016.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/06/2016] [Accepted: 10/06/2016] [Indexed: 12/19/2022]
Abstract
This review categorizes functionally validated actions of defined scorpion toxin (SCTX) neuropeptides across ion channel subclasses, highlighting key trends in this rapidly evolving field. Scorpion envenomation is a common event in many tropical and subtropical countries, with neuropharmacological actions, particularly autonomic nervous system modulation, causing significant mortality. The primary active agents within scorpion venoms are a diverse group of small neuropeptides that elicit specific potent actions across a wide range of ion channel classes. The identification and functional characterisation of these SCTX peptides has tremendous potential for development of novel pharmaceuticals that advance knowledge of ion channels and establish lead compounds for treatment of excitable tissue disorders. This review delineates the unique specificities of 320 individual SCTX peptides that collectively act on 41 ion channel subclasses. Thus the SCTX research field has significant translational implications for pathophysiology spanning neurotransmission, neurohumoral signalling, sensori-motor systems and excitation-contraction coupling. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- David M Housley
- College of Medicine and Dentistry, Cairns Campus, James Cook University, Cairns, Queensland 4878, Australia; Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia.
| | - Gary D Housley
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia
| | - Michael J Liddell
- Centre for Tropical Environmental and Sustainability Science and College of Science & Engineering, Cairns Campus, James Cook University, Cairns, Queensland 4878, Australia
| | - Ernest A Jennings
- College of Medicine and Dentistry, Cairns Campus, James Cook University, Cairns, Queensland 4878, Australia; Centre for Biodiscovery and Molecular Development of Therapeutics, James Cook University, Queensland 4878, Australia; Australian Institute of Tropical Health and Medicine, James Cook University, Cairns Campus, QLD, Australia
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Ehling P, Meuth P, Eichinger P, Herrmann AM, Bittner S, Pawlowski M, Pankratz S, Herty M, Budde T, Meuth SG. Human T cells in silico: Modelling their electrophysiological behaviour in health and disease. J Theor Biol 2016; 404:236-250. [PMID: 27288542 DOI: 10.1016/j.jtbi.2016.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/27/2016] [Accepted: 06/01/2016] [Indexed: 01/27/2023]
Abstract
Although various types of ion channels are known to have an impact on human T cell effector functions, their exact mechanisms of influence are still poorly understood. The patch clamp technique is a well-established method for the investigation of ion channels in neurons and T cells. However, small cell sizes and limited selectivity of pharmacological blockers restrict the value of this experimental approach. Building a realistic T cell computer model therefore can help to overcome these kinds of limitations as well as reduce the overall experimental effort. The computer model introduced here was fed off ion channel parameters from literature and new experimental data. It is capable of simulating the electrophysiological behaviour of resting and activated human CD4(+) T cells under basal conditions and during extracellular acidification. The latter allows for the very first time to assess the electrophysiological consequences of tissue acidosis accompanying most forms of inflammation.
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Affiliation(s)
- Petra Ehling
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany.
| | - Patrick Meuth
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Paul Eichinger
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany; Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München TUM, Ismaninger Strasse 22, 81675 Munich, Germany
| | - Alexander M Herrmann
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Matthias Pawlowski
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany; Wellcome Trust and MRC Cambridge Stem Cell Institute, and Anne McLaren Laboratory for Regenerative Medicine, University of Cambridge, West Forvie Building, Forvie Site, Robinson Way, Cambridge, UK
| | - Susann Pankratz
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Michael Herty
- RWTH Aachen University, Mathematics (Continuous optimization), Templergraben 55, 52056 Aachen, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Robert-Koch-Str. 27a, 48149 Münster, Germany
| | - Sven G Meuth
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
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Olamendi-Portugal T, Bartok A, Zamudio-Zuñiga F, Balajthy A, Becerril B, Panyi G, Possani LD. Isolation, chemical and functional characterization of several new K+-channel blocking peptides from the venom of the scorpion Centruroides tecomanus. Toxicon 2016; 115:1-12. [DOI: 10.1016/j.toxicon.2016.02.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/04/2016] [Accepted: 02/18/2016] [Indexed: 11/29/2022]
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Kovach CP, Al Koborssy D, Huang Z, Chelette BM, Fadool JM, Fadool DA. Mitochondrial Ultrastructure and Glucose Signaling Pathways Attributed to the Kv1.3 Ion Channel. Front Physiol 2016; 7:178. [PMID: 27242550 PMCID: PMC4871887 DOI: 10.3389/fphys.2016.00178] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/04/2016] [Indexed: 12/20/2022] Open
Abstract
Gene-targeted deletion of the potassium channel Kv1.3 (Kv1.3−∕−) results in “Super-smeller” mice with a sensory phenotype that includes an increased olfactory ability linked to changes in olfactory circuitry, increased abundance of olfactory cilia, and increased expression of odorant receptors and the G-protein, Golf. Kv1.3−∕− mice also have a metabolic phenotype including lower body weight and decreased adiposity, increased total energy expenditure (TEE), increased locomotor activity, and resistance to both diet- and genetic-induced obesity. We explored two cellular aspects to elucidate the mechanism by which loss of Kv1.3 channel in the olfactory bulb (OB) may enhance glucose utilization and metabolic rate. First, using in situ hybridization we find that Kv1.3 and the insulin-dependent glucose transporter type 4 (GLUT4) are co-localized to the mitral cell layer of the OB. Disruption of Kv1.3 conduction via construction of a pore mutation (W386F Kv1.3) was sufficient to independently translocate GLUT4 to the plasma membrane in HEK 293 cells. Because olfactory sensory perception and the maintenance of action potential (AP) firing frequency by mitral cells of the OB is highly energy demanding and Kv1.3 is also expressed in mitochondria, we next explored the structure of this organelle in mitral cells. We challenged wildtype (WT) and Kv1.3−∕− male mice with a moderately high-fat diet (MHF, 31.8 % kcal fat) for 4 months and then examined OB ultrastructure using transmission electron microscopy. In WT mice, mitochondria were significantly enlarged following diet-induced obesity (DIO) and there were fewer mitochondria, likely due to mitophagy. Interestingly, mitochondria were significantly smaller in Kv1.3−∕− mice compared with that of WT mice. Similar to their metabolic resistance to DIO, the Kv1.3−∕− mice had unchanged mitochondria in terms of cross sectional area and abundance following a challenge with modified diet. We are very interested to understand how targeted disruption of the Kv1.3 channel in the OB can modify TEE. Our study demonstrates that Kv1.3 regulates mitochondrial structure and alters glucose utilization; two important metabolic changes that could drive whole system changes in metabolism initiated at the OB.
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Affiliation(s)
- Christopher P Kovach
- Program in Neuroscience, Florida State UniversityTallahassee, FL, USA; Department of Biological Science, Florida State UniversityTallahassee, FL, USA
| | - Dolly Al Koborssy
- Program in Neuroscience, Florida State University Tallahassee, FL, USA
| | - Zhenbo Huang
- Program in Neuroscience, Florida State University Tallahassee, FL, USA
| | | | - James M Fadool
- Program in Neuroscience, Florida State UniversityTallahassee, FL, USA; Department of Biological Science, Florida State UniversityTallahassee, FL, USA
| | - Debra A Fadool
- Program in Neuroscience, Florida State UniversityTallahassee, FL, USA; Department of Biological Science, Florida State UniversityTallahassee, FL, USA; Institute of Molecular Biophysics, Florida State UniversityTallahassee, FL, USA
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The Gatekeepers in the Mouse Ophthalmic Artery: Endothelium-Dependent Mechanisms of Cholinergic Vasodilation. Sci Rep 2016; 6:20322. [PMID: 26831940 PMCID: PMC4735817 DOI: 10.1038/srep20322] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/04/2016] [Indexed: 01/25/2023] Open
Abstract
Cholinergic regulation of arterial luminal diameter involves intricate network of intercellular communication between the endothelial and smooth muscle cells that is highly dependent on the molecular mediators released by the endothelium. Albeit the well-recognized contribution of nitric oxide (NO) towards vasodilation, the identity of compensatory mechanisms that maintain vasomotor tone when NO synthesis is deranged remain largely unknown in the ophthalmic artery. This is the first study to identify the vasodilatory signalling mechanisms of the ophthalmic artery employing wild type mice. Acetylcholine (ACh)-induced vasodilation was only partially attenuated when NO synthesis was inhibited. Intriguingly, the combined blocking of cytochrome P450 oxygenase (CYP450) and lipoxygenase (LOX), as well as CYP450 and gap junctions, abolished vasodilation; demonstrating that the key compensatory mechanisms comprise arachidonic acid metabolites which, work in concert with gap junctions for downstream signal transmission. Furthermore, the voltage-gated potassium ion channel, Kv1.6, was functionally relevant in mediating vasodilation. Its localization was found exclusively in the smooth muscle. In conclusion, ACh-induced vasodilation of mouse ophthalmic artery is mediated in part by NO and predominantly via arachidonic acid metabolites, with active involvement of gap junctions. Particularly, the Kv1.6 channel represents an attractive therapeutic target in ophthalmopathologies when NO synthesis is compromised.
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