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Titaux-Delgado G, Lopez-Giraldo AE, Carrillo E, Cofas-Vargas LF, Carranza LE, López-Vera E, García-Hernández E, Del Rio-Portilla F. Beta-KTx14.3, a scorpion toxin, blocks the human potassium channel KCNQ1. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2023; 1871:140906. [PMID: 36918120 DOI: 10.1016/j.bbapap.2023.140906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/25/2023] [Accepted: 03/06/2023] [Indexed: 03/14/2023]
Abstract
Potassium channels play a key role in regulating many physiological processes, thus, alterations in their proper functioning can lead to the development of several diseases. Hence, the search for compounds capable of regulating the activity of these channels constitutes an intense field of investigation. Potassium scorpion toxins are grouped into six subfamilies (α, β, γ, κ, δ, and λ). However, experimental structures and functional analyses of the long chain β-KTx subfamily are lacking. In this study, we recombinantly produced the toxins TcoKIK and beta-KTx14.3 present in the venom of Tityus costatus and Lychas mucronatus scorpions, respectively. The 3D structures of these β-KTx toxins were determined by nuclear magnetic resonance. In both toxins, the N-terminal region is unstructured, while the C-terminal possesses the classic CSα/β motif. TcoKIK did not show any clear activity against frog Shaker and human KCNQ1 potassium channels; however, beta-KTx14.3 was able to block the KCNQ1 channel. The toxin-channel interaction mode was investigated using molecular dynamics simulations. The results showed that this toxin could form a stable network of polar-to-polar and hydrophobic interactions with KCNQ1, involving key conserved residues in both molecular partners. The discovery and characterization of a toxin capable of inhibiting KCNQ1 pave the way for the future development of novel drugs for the treatment of human diseases caused by the malfunction of this potassium channel. STATEMENT OF SIGNIFICANCE: Scorpion toxins have been shown to rarely block human KCNQ1 channels, which participate in the regulation of cardiac processes. In this study, we obtained recombinant beta-KTx14.3 and TcoKIK toxins and determined their 3D structures by nuclear magnetic resonance. Electrophysiological studies and molecular dynamics models were employed to examine the interactions between these two toxins and the human KCNQ1, which is the major driver channel of cardiac repolarization; beta-KTx14.3 was found to block effectively this channel. Our findings provide insights for the development of novel toxin-based drugs for the treatment of cardiac channelopathies involving KCNQ1-like channels.
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Affiliation(s)
- Gustavo Titaux-Delgado
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, CU, Ciudad de México 04510, Mexico
| | - Andrea Estefanía Lopez-Giraldo
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, CU, Ciudad de México 04510, Mexico
| | - Elisa Carrillo
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Luis Fernando Cofas-Vargas
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, CU, Ciudad de México 04510, Mexico
| | - Luis Enrique Carranza
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, CU, Ciudad de México 04510, Mexico
| | - Estuardo López-Vera
- Laboratorio de Toxinología Marina, Unidad Académica de Ecología y Biodiversidad Acuática, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México 04510, Mexico
| | - Enrique García-Hernández
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, CU, Ciudad de México 04510, Mexico.
| | - Federico Del Rio-Portilla
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, CU, Ciudad de México 04510, Mexico.
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Filipis L, Canepari M. Can neuron modeling constrained by ultrafast imaging data extract the native function of ion channels? Front Comput Neurosci 2023; 17:1192421. [PMID: 37293354 PMCID: PMC10244549 DOI: 10.3389/fncom.2023.1192421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/02/2023] [Indexed: 06/10/2023] Open
Affiliation(s)
- Luiza Filipis
- Univ Grenoble Alpes, CNRS, LIPhy, Grenoble, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Valbonne, France
| | - Marco Canepari
- Univ Grenoble Alpes, CNRS, LIPhy, Grenoble, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Valbonne, France
- Institut National de la Santé et Recherche Médicale, Paris, France
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NMDA Receptor Activation and Ca 2+/PKC Signaling in Nicotine-Induced GABA Transport Shift in Embryonic Chick Retina. Neurochem Res 2023; 48:2104-2115. [PMID: 36792758 DOI: 10.1007/s11064-023-03870-7] [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: 08/15/2022] [Revised: 12/23/2022] [Accepted: 01/21/2023] [Indexed: 02/17/2023]
Abstract
Nicotinic receptors are present in the retina of different vertebrates, and in the chick retina, it is present during early development throughout to post-hatching. These receptors are activated by nicotine, an alkaloid with addictive and neurotransmitter release modulation properties, such as GABA signaling. Here we evaluated the mechanisms of nicotine signaling in the avian retina during the development of neuron-glia cells at a stage where synapses are peaking. Nicotine almost halved [3H]-GABA uptake, reducing it by 45% whilst increasing more than two-fold [3H]-GABA release in E12 embryonic chick retinas. Additionally, nicotine mediated a 33% increase in [3H]-D-aspartate release. MK-801 50 μM blocked 66% of nicotine-induced [3H]-GABA release and Gö 6983 100 nM prevented the nicotine-induced reduction in [3H]-GABA uptake by rescuing 40% of this neurotransmitter uptake, implicating NMDAR and PKC (respectively) in the nicotinic responses. In addition, NO-711 prevented [3H]-GABA uptake and release induced by nicotine. Furthermore, the relevance of calcium influx for PKC activation was evidenced through fura-2 imaging. We conclude that the shift of GABA transport mediated by nicotine promotes GABA release by inducing transporter reversal via nicotine-induced EAA release through EAATs, or by a direct effect of nicotine in activating nicotinic receptors permeable to calcium and promoting PKC pathway activation and shifting GAT-1 activity, both prompting calcium influx, and activation of the PKC pathway and shifting GAT-1 activity.
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Colom-Casasnovas A, Garay E, Cisneros-Mejorado A, Aguilar MB, Lazcano-Pérez F, Arellano RO, Sánchez-Rodríguez J. Sea anemone Bartholomea annulata venom inhibits voltage-gated Na+ channels and activates GABAA receptors from mammals. Sci Rep 2022; 12:5352. [PMID: 35354863 PMCID: PMC8967859 DOI: 10.1038/s41598-022-09339-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/17/2022] [Indexed: 11/18/2022] Open
Abstract
Toxin production in nematocysts by Cnidaria phylum represents an important source of bioactive compounds. Using electrophysiology and, heterologous expression of mammalian ion channels in the Xenopus oocyte membrane, we identified two main effects produced by the sea anemone Bartholomea annulata venom. Nematocysts isolation and controlled discharge of their content, revealed that venom had potent effects on both voltage-dependent Na+ (Nav) channels and GABA type A channel receptors (GABAAR), two essential proteins in central nervous system signaling. Unlike many others sea anemone toxins, which slow the inactivation rate of Nav channels, B. annulata venom potently inhibited the neuronal action potential and the Na+ currents generated by distinct Nav channels opening, including human TTX-sensitive (hNav1.6) and TTX-insensitive Nav channels (hNav1.5). A second effect of B. annulata venom was an agonistic action on GABAAR that activated distinct receptors conformed by either α1β2γ2, α3β2γ1 or, ρ1 homomeric receptors. Since GABA was detected in venom samples by ELISA assay at low nanomolar range, it was excluded that GABA from nematocysts directly activated the GABAARs. This revealed that substances in B. annulata nematocysts generated at least two potent and novel effects on mammalian ion channels that are crucial for nervous system signaling.
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Morgan M, Thai J, Trinh P, Habib M, Effendi KN, Ivanusic JJ. ASIC3 inhibition modulates inflammation-induced changes in the activity and sensitivity of Aδ and C fiber sensory neurons that innervate bone. Mol Pain 2021; 16:1744806920975950. [PMID: 33280501 PMCID: PMC7724402 DOI: 10.1177/1744806920975950] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Acid Sensing Ion Channel 3 (ASIC3) is a non-selective cation channel that is
activated by acidification, and is known to have a role in regulating
inflammatory pain. It has pro-algesic roles in a range of conditions that
present with bone pain, but the mechanism for this has not yet been
demonstrated. We aimed to determine if ASIC3 is expressed in Aδ and/or C fiber
bone afferent neurons, and to explore its role in the activation and
sensitization of bone afferent neurons after acute inflammation. A combination
of retrograde tracing and immunohistochemistry was used to determine expression
of ASIC3 in the soma of bone afferent neurons. A novel, in
vivo, electrophysiological bone-nerve preparation was used to make
recordings of the activity and sensitivity of bone afferent neurons in the
presence of carrageenan-induced inflammation, with and without the selective
ASIC3 inhibitor APET×2. A substantial proportion of bone afferent neurons
express ASIC3, including unmyelinated (neurofilament poor) and small diameter
myelinated (neurofilament rich) neurons that are likely to be C and Aδ nerve
fibers respectively. Electrophysiological recordings revealed that application
of APET×2 to the marrow cavity inhibited carrageenan-induced spontaneous
activity of C and Aδ fiber bone afferent neurons. APET×2 also inhibited
carrageenan-induced sensitization of Aδ and C fiber bone afferent neurons to
mechanical stimulation, but had no effect on the sensitivity of bone afferent
neurons in the absence of inflammation. This evidence supports a role for ASIC3
in the pathogenesis of pain associated with inflammation of the bone.
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Affiliation(s)
- Michael Morgan
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Jenny Thai
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Phu Trinh
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Mohamed Habib
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Kelly N Effendi
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Jason J Ivanusic
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
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Saikia C, Ben-Nissan G, Reuveny E, Karbat I. Production of recombinant venom peptides as tools for ion channel research. Methods Enzymol 2021; 654:169-201. [PMID: 34120712 DOI: 10.1016/bs.mie.2021.01.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Animal venom is a rich source for peptide toxins that bind and modulate the function of ion channels. Owing to their ability to bind receptor sites on the channel protein with high affinity and specificity, peptide neurotoxins have become an indispensable tool for ion channel research. Recent breakthroughs in structural biology and advances in computer simulations of biomolecules have sparked a new interest in animal toxins as probes of channel protein structure and function. Here, we focus on methods used to produce animal toxins for research purposes using recombinant expression. The specific challenges associated with heterologous production of venom peptides are discussed, and several methods targeting these issues are presented with an emphasis on E. coli based systems. An efficient protocol for the bacterial expression, folding, and purification of recombinant venom peptides is described.
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Affiliation(s)
- Chandamita Saikia
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Gili Ben-Nissan
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Eitan Reuveny
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
| | - Izhar Karbat
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
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Israel MR, Dash TS, Bothe SN, Robinson SD, Deuis JR, Craik DJ, Lampert A, Vetter I, Durek T. Characterization of Synthetic Tf2 as a Na V1.3 Selective Pharmacological Probe. Biomedicines 2020; 8:biomedicines8060155. [PMID: 32545167 PMCID: PMC7345637 DOI: 10.3390/biomedicines8060155] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/02/2020] [Accepted: 06/05/2020] [Indexed: 12/17/2022] Open
Abstract
NaV1.3 is a subtype of the voltage-gated sodium channel family. It has been implicated in the pathogenesis of neuropathic pain, although the contribution of this channel to neuronal excitability is not well understood. Tf2, a β-scorpion toxin previously identified from the venom of Tityus fasciolatus, has been reported to selectively activate NaV1.3. Here, we describe the activity of synthetic Tf2 and assess its suitability as a pharmacological probe for NaV1.3. As described for the native toxin, synthetic Tf2 (1 µM) caused early channel opening, decreased the peak current, and shifted the voltage dependence of NaV1.3 activation in the hyperpolarizing direction by −11.3 mV, with no activity at NaV1.1, NaV1.2, and NaV1.4-NaV1.8. Additional activity was found at NaV1.9, tested using the hNav1.9_C4 chimera, where Tf2 (1 µM) shifted the voltage dependence of activation by −6.3 mV. In an attempt to convert Tf2 into an NaV1.3 inhibitor, we synthetized the analogue Tf2[S14R], a mutation previously described to remove the excitatory activity of related β-scorpion toxins. Indeed, Tf2[S14R](10 µM) had reduced excitatory activity at NaV1.3, although it still caused a small −5.8 mV shift in the voltage dependence of activation. Intraplantar injection of Tf2 (1 µM) in mice caused spontaneous flinching and swelling, which was not reduced by the NaV1.1/1.3 inhibitor ICA-121431 nor in NaV1.9-/- mice, suggesting off-target activity. In addition, despite a loss of excitatory activity, intraplantar injection of Tf2[S14R](10 µM) still caused swelling, providing strong evidence that Tf2 has additional off-target activity at one or more non-neuronal targets. Therefore, due to activity at NaV1.9 and other yet to be identified target(s), the use of Tf2 as a selective pharmacological probe may be limited.
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Affiliation(s)
- Mathilde R. Israel
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (M.R.I.); (T.S.D.); (S.D.R.); (J.R.D.); (D.J.C.)
| | - Thomas S. Dash
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (M.R.I.); (T.S.D.); (S.D.R.); (J.R.D.); (D.J.C.)
| | - Stefanie N. Bothe
- Institute of Physiology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (S.N.B.); (A.L.)
- Research Training Group 2416 MultiSenses-MultiScales, RWTH Aachen University, 52074 Aachen, Germany
| | - Samuel D. Robinson
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (M.R.I.); (T.S.D.); (S.D.R.); (J.R.D.); (D.J.C.)
| | - Jennifer R. Deuis
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (M.R.I.); (T.S.D.); (S.D.R.); (J.R.D.); (D.J.C.)
| | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (M.R.I.); (T.S.D.); (S.D.R.); (J.R.D.); (D.J.C.)
| | - Angelika Lampert
- Institute of Physiology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (S.N.B.); (A.L.)
- Research Training Group 2416 MultiSenses-MultiScales, RWTH Aachen University, 52074 Aachen, Germany
- Research Training Group 2415 ME3T, RWTH Aachen University, 52074 Aachen, Germany
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (M.R.I.); (T.S.D.); (S.D.R.); (J.R.D.); (D.J.C.)
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
- Correspondence: (I.V.); (T.D.); Tel.: +61-7-3346-2660 (I.V.); +61-7-3346-2021 (T.D.)
| | - Thomas Durek
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (M.R.I.); (T.S.D.); (S.D.R.); (J.R.D.); (D.J.C.)
- Correspondence: (I.V.); (T.D.); Tel.: +61-7-3346-2660 (I.V.); +61-7-3346-2021 (T.D.)
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Yin K, Deuis JR, Dekan Z, Jin AH, Alewood PF, King GF, Herzig V, Vetter I. Addition of K22 Converts Spider Venom Peptide Pme2a from an Activator to an Inhibitor of Na V1.7. Biomedicines 2020; 8:biomedicines8020037. [PMID: 32092883 PMCID: PMC7167818 DOI: 10.3390/biomedicines8020037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/13/2020] [Accepted: 02/17/2020] [Indexed: 02/07/2023] Open
Abstract
Spider venom is a novel source of disulfide-rich peptides with potent and selective activity at voltage-gated sodium channels (NaV). Here, we describe the discovery of μ-theraphotoxin-Pme1a and μ/δ-theraphotoxin-Pme2a, two novel peptides from the venom of the Gooty Ornamental tarantula Poecilotheria metallica that modulate NaV channels. Pme1a is a 35 residue peptide that inhibits NaV1.7 peak current (IC50 334 ± 114 nM) and shifts the voltage dependence of activation to more depolarised membrane potentials (V1/2 activation: Δ = +11.6 mV). Pme2a is a 33 residue peptide that delays fast inactivation and inhibits NaV1.7 peak current (EC50 > 10 μM). Synthesis of a [+22K]Pme2a analogue increased potency at NaV1.7 (IC50 5.6 ± 1.1 μM) and removed the effect of the native peptide on fast inactivation, indicating that a lysine at position 22 (Pme2a numbering) is important for inhibitory activity. Results from this study may be used to guide the rational design of spider venom-derived peptides with improved potency and selectivity at NaV channels in the future.
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Affiliation(s)
- Kathleen Yin
- Centre for Health Informatics, Australian Institute of Health Innovation, Macquarie University, North Ryde, NSW 2109, Australia;
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.R.D.); (Z.D.); (P.F.A.); (G.F.K.)
| | - Jennifer R. Deuis
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.R.D.); (Z.D.); (P.F.A.); (G.F.K.)
| | - Zoltan Dekan
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.R.D.); (Z.D.); (P.F.A.); (G.F.K.)
| | - Ai-Hua Jin
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.R.D.); (Z.D.); (P.F.A.); (G.F.K.)
| | - Paul F. Alewood
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.R.D.); (Z.D.); (P.F.A.); (G.F.K.)
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.R.D.); (Z.D.); (P.F.A.); (G.F.K.)
| | - Volker Herzig
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.R.D.); (Z.D.); (P.F.A.); (G.F.K.)
- School of Science & Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia
- Correspondence: (V.H.); (I.V.); Tel.: +61-7-5456-5382 (V.H.); +61-7-3346-2660 (I.V.)
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.R.D.); (Z.D.); (P.F.A.); (G.F.K.)
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
- Correspondence: (V.H.); (I.V.); Tel.: +61-7-5456-5382 (V.H.); +61-7-3346-2660 (I.V.)
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