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Sakai S, Fujita Y, Juichi H, Nakagawa Y, Miyashita M. Chemical synthesis and functional characterization of LaIT3, an insecticidal two-domain peptide in Liocheles australasiae venom. Toxicon 2024; 238:107564. [PMID: 38113946 DOI: 10.1016/j.toxicon.2023.107564] [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: 10/06/2023] [Revised: 11/29/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
LaIT3, belonging to the β-KTx family, is an insecticidal peptide in the venom of the Liocheles australasiae scorpion. Peptides in the family consist of two structural domains: an N-terminal domain with an α-helical structure common to antimicrobial peptides and a C-terminal domain with a structure stabilized by three disulfide bonds common to ion-channel blocking peptides. However, the contribution of each domain of LaIT3 to its activity remained unknown. In addition, some peptidic components are known to be enzymatically cleaved in the venom, which generates partial peptides. In our study, we searched for partial peptides of LaIT3 using LC/MS analysis and found peptides generated by cleavage at the central region of LaIT3. We subsequently synthesized full-length LaIT3 and its partial peptides to evaluate their insecticidal activity. The results, showing that only full-length LaIT3 is active, indicate that the insecticidal activity of LaIT3 depends on the presence of both N-terminal and C-terminal domains. Furthermore, LaIT3 did not exhibit the cytolytic activity against insect cells and showed only weak antibacterial activity. These findings suggest that its action is not due to a simple membrane disruption effect but instead due to actions on specific target molecules, including ion channels.
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Affiliation(s)
- Shoichi Sakai
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Yuumi Fujita
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Hironori Juichi
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Yoshiaki Nakagawa
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Masahiro Miyashita
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan.
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2
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da Silva CN, Nunes KP, Dourado LFN, Vieira TO, Mariano XM, Cunha Junior ADS, de Lima ME. From the PnTx2-6 Toxin to the PnPP-19 Engineered Peptide: Therapeutic Potential in Erectile Dysfunction, Nociception, and Glaucoma. Front Mol Biosci 2022; 9:831823. [PMID: 35480885 PMCID: PMC9035689 DOI: 10.3389/fmolb.2022.831823] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
The venom of the “armed” spider Phoneutria nigriventer comprises several potent toxins. One of the most toxic components from this venom is the neurotoxin PnTx2-6 (LD50 = ∼ 0.7 μg/mouse, 48 residues, five disulfide bridges, MW = 5,289.31 Da), which slows down the inactivation of various Na+ channels. In mice and rats, this toxin causes priapism, an involuntary and painful erection, similar to what is observed in humans bitten by P. nigriventer. While not completely elucidated, it is clear that PnTx2-6 potentiates erectile function via NO/cGMP signaling, but it has many off-target effects. Seeking to obtain a simpler and less toxic molecule able to retain the pharmacological properties of this toxin, we designed and synthesized the peptide PnPP-19 (19 residues, MW = 2,485.6 Da), representing a discontinuous epitope of PnTx2-6. This synthetic peptide also potentiates erectile function via NO/cGMP, but it does not target Na+ channels, and therefore, it displays nontoxic properties in animals even at high doses. PnPP-19 effectively potentiates erectile function not only after subcutaneous or intravenous administration but also following topical application. Surprisingly, PnPP-19 showed central and peripheral antinociceptive activity involving the opioid and cannabinoid systems, suggesting applicability in nociception. Furthermore, considering that PnPP-19 increases NO availability in the corpus cavernosum, this peptide was also tested in a model of induced intraocular hypertension, characterized by low NO levels, and it showed promising results by decreasing the intraocular pressure which prevents retinal damage. Herein, we discuss how was engineered this smaller active non-toxic peptide with promising results in the treatment of erectile dysfunction, nociception, and glaucoma from the noxious PnTx2-6, as well as the pitfalls of this ongoing journey.
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Affiliation(s)
- Carolina Nunes da Silva
- Departmentamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- *Correspondence: Maria Elena de Lima, ; Carolina Nunes da Silva, ; Kenia Pedrosa Nunes,
| | - Kenia Pedrosa Nunes
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
- *Correspondence: Maria Elena de Lima, ; Carolina Nunes da Silva, ; Kenia Pedrosa Nunes,
| | | | - Thayllon Oliveira Vieira
- Programa de Pós-Graduação em Medicina e Biomedicina Faculdade Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
| | - Xavier Maia Mariano
- Programa de Pós-Graduação em Medicina e Biomedicina Faculdade Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
| | | | - Maria Elena de Lima
- Departmentamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Programa de Pós-Graduação em Medicina e Biomedicina Faculdade Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
- *Correspondence: Maria Elena de Lima, ; Carolina Nunes da Silva, ; Kenia Pedrosa Nunes,
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Oliveira CFB, Alves DP, Emerich BL, de Figueiredo SG, Cordeiro MDN, Borges MH, Richardson M, Pimenta AMDC, Duarte IDG, de Lima ME. Antinociceptive effect of PnTx4(5-5), a peptide from Phoneutria nigriventer spider venom, in rat models and the involvement of glutamatergic system. J Venom Anim Toxins Incl Trop Dis 2019; 25:e20190022. [PMID: 31467512 PMCID: PMC6706083 DOI: 10.1590/1678-9199-jvatitd-2019-0022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 07/10/2019] [Indexed: 03/12/2023] Open
Abstract
Background: The venom of Phoneutria nigriventer spider is a source of
numerous bioactive substances, including some toxins active in insects. An
example is PnTx4(5-5) that shows a high insecticidal activity and no
apparent toxicity to mice, although it inhibited NMDA-evoked currents in rat
hippocampal neurons. In this work the analgesic activity of PnTx4(5-5)
(renamed Γ-ctenitoxin-Pn1a) was investigated. Methods: The antinociceptive activity was evaluated using the paw pressure test in
rats, after hyperalgesia induction with intraplantar injection of
carrageenan or prostaglandin E2 (PGE2). Results: PnTx4(5-5), subcutaneously injected, was able to reduce the hyperalgesia
induced by PGE2 in rat paw, demonstrating a systemic effect.
PnTx4(5-5) administered in the plantar surface of the paw caused a
peripheral and dose-dependent antinociceptive effect on hyperalgesia induced
by carrageenan or PGE2. The hyperalgesic effect observed in these
two pain models was completely reversed with 5 µg of PnTx4(5-5).
Intraplantar administration of L-glutamate induced hyperalgesic effect that
was significantly reverted by 5 μg of PnTx4(5-5) injection in rat paw. Conclusion: The antinociceptive effect for PnTx4(5-5) was demonstrated against different
rat pain models, i.e. induced by PGE2, carrageenan or glutamate.
We suggest that the antinociceptive effect of PnTx4(5-5) may be related to
an inhibitory activity on the glutamatergic system.
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Affiliation(s)
- Camila Franco Batista Oliveira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brasil
| | - Daniela Pereira Alves
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brasil
| | - Bruna Luiza Emerich
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brasil
| | - Suely Gomes de Figueiredo
- Departamento de Ciências Fisiológicas, Centro de Ciências da Saúde, Universidade Federal do Espirito Santo (UFES), Vitória (ES), Brasil
| | - Marta do Nascimento Cordeiro
- Centro de Pesquisa e Desenvolvimento Professor Carlos Diniz, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brasil
| | - Márcia Helena Borges
- Centro de Pesquisa e Desenvolvimento Professor Carlos Diniz, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brasil
| | - Michael Richardson
- Centro de Pesquisa e Desenvolvimento Professor Carlos Diniz, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brasil
| | - Adriano Monteiro de Castro Pimenta
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brasil
| | - Igor Dimitri Gama Duarte
- Departamento de Fisiologia e Farmacologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brasil
| | - Maria Elena de Lima
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brasil.,Instituto de Ensino e Pesquisa, Santa Casa de Belo Horizonte, Rua Domingos Vieira, 590, Santa Efigênia, Belo Horizonte, MG, CEP 30.150-240, Brasil
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Isolation and Characterization of Insecticidal Toxins from the Venom of the North African Scorpion, Buthacus leptochelys. Toxins (Basel) 2019; 11:toxins11040236. [PMID: 31027216 PMCID: PMC6521144 DOI: 10.3390/toxins11040236] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/16/2019] [Accepted: 04/22/2019] [Indexed: 11/17/2022] Open
Abstract
Various bioactive peptides have been identified in scorpion venom, but there are many scorpion species whose venom has not been investigated. In this study, we characterized venom components of the North African scorpion, Buthacus leptochelys, by mass spectrometric analysis and evaluated their insect toxicity. This is the first report of chemical and biological characterization of the B. leptochelys venom. LC/MS analysis detected at least 148 components in the venom. We isolated four peptides that show insect toxicity (Bl-1, Bl-2, Bl-3, and Bl-4) through bioassay-guided HPLC fractionation. These toxins were found to be similar to scorpion α- and β-toxins based on their N-terminal sequences. Among them, the complete primary structure of Bl-1 was determined by combination of Edman degradation and MS/MS analysis. Bl-1 is composed of 67 amino acid residues and crosslinked with four disulfide bonds. Since Bl-1 shares high sequence similarity with α-like toxins, it is likely that it acts on Na+ channels of both insects and mammals.
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Krämer J, Pohl H, Predel R. Venom collection and analysis in the pseudoscorpion Chelifer cancroides (Pseudoscorpiones: Cheliferidae). Toxicon 2019; 162:15-23. [PMID: 30796931 DOI: 10.1016/j.toxicon.2019.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 02/09/2019] [Accepted: 02/13/2019] [Indexed: 11/30/2022]
Abstract
Pseudoscorpions are very small arthropods with almost worldwide distribution. They possess a unique venom delivery system in the chelal hands of their pedipalps that has evolved independently from that of scorpions and spiders. Studies on the venom composition of pseudoscorpions are very rare. Recently, the potential venom composition of the pseudoscorpion Synsphyronus apimelus Harvey, 1987 (Pseudoscorpiones: Garypidae) has been studied by transcriptome analysis. However, a proteome analysis of venom to identify the genuine venom compounds of pseudoscorpions has not yet been performed. In our study, we have developed a non-invasive approach for extracting minute amounts of venom, which for the first time allowed collecting pure venom samples of pseudoscorpions with minimal contaminations and high reproducibility. These experiments first required a morphological investigation of the venom delivery system with a focus on the role of the lamina defensor in the release of venom. Likely, the venom delivery system of pseudoscorpions has a mechanism that prevents the release of venom if the prey is not successfully penetrated by a venom tooth. Electrical stimulation of a gland-containing chelal hand in combination with a mechanical stimulation of the lamina defensor at the base of the venom tooth resulted in an average of 5 nl of collected venom. The utility of the method was then validated by repeated venom extractions and subsequent analysis of the venom composition using MALDI-TOF mass fingerprinting. Subsequent proteomics analysis in combination with transcriptome analyses of chelal hand tissue has identified the first genuine venom compounds of pseudoscorpions with putative antimicrobial peptides. For our experiments, we used the house pseudoscorpion Chelifer cancroides (Linnaeus, 1758) (Pseudoscorpiones: Cheliferidae).
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Affiliation(s)
- Jonas Krämer
- Institute for Zoology, University of Cologne, D-50674, Cologne, Germany.
| | - Hans Pohl
- Institut für Zoologie und Evolutionsforschung, Friedrich-Schiller-Universität Jena, D-07743, Jena, Germany
| | - Reinhard Predel
- Institute for Zoology, University of Cologne, D-50674, Cologne, Germany.
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Peigneur S, de Lima ME, Tytgat J. Phoneutria nigriventer venom: A pharmacological treasure. Toxicon 2018; 151:96-110. [DOI: 10.1016/j.toxicon.2018.07.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/27/2018] [Accepted: 07/05/2018] [Indexed: 12/15/2022]
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7
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Zornetta I, Scorzeto M, Mendes Dos Reis PV, De Lima ME, Montecucco C, Megighian A, Rossetto O. Electrophysiological Characterization of the Antarease Metalloprotease from Tityus serrulatus Venom. Toxins (Basel) 2017; 9:E81. [PMID: 28264432 PMCID: PMC5371836 DOI: 10.3390/toxins9030081] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 02/15/2017] [Accepted: 02/20/2017] [Indexed: 12/14/2022] Open
Abstract
Scorpions are among the oldest venomous living organisms and the family Buthidae is the largest and most medically relevant one. Scorpion venoms include many toxic peptides, but recently, a metalloprotease from Tityus serrulatus called antarease was reported to be capable of cleaving VAMP2, a protein involved in the neuroparalytic syndromes of tetanus and botulism. We have produced antarease and an inactive metalloprotease mutant in a recombinant form and analyzed their enzymatic activity on recombinant VAMP2 in vitro and on mammalian and insect neuromuscular junction. The purified recombinant antarease paralyzed the neuromuscular junctions of mice and of Drosophila melanogaster whilst the mutant was inactive. We were unable to demonstrate any cleavage of VAMP2 under conditions which leads to VAMP proteolysis by botulinum neurotoxin type B. Antarease caused a reduced release probability, mainly due to defects upstream of the synaptic vesicles fusion process. Paired pulse experiments indicate that antarease might proteolytically inactivate a voltage-gated calcium channel.
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Affiliation(s)
- Irene Zornetta
- Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy.
| | - Michele Scorzeto
- Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy.
| | - Pablo Victor Mendes Dos Reis
- Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil.
| | - Maria E De Lima
- Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil.
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy.
| | - Aram Megighian
- Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy.
| | - Ornella Rossetto
- Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy.
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8
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Bothriurus bonariensis scorpion venom activates voltage-dependent sodium channels in insect and mammalian nervous systems. Chem Biol Interact 2016; 258:1-9. [DOI: 10.1016/j.cbi.2016.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 08/05/2016] [Accepted: 08/15/2016] [Indexed: 01/12/2023]
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9
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Herzig V, Ikonomopoulou M, Smith JJ, Dziemborowicz S, Gilchrist J, Kuhn-Nentwig L, Rezende FO, Moreira LA, Nicholson GM, Bosmans F, King GF. Molecular basis of the remarkable species selectivity of an insecticidal sodium channel toxin from the African spider Augacephalus ezendami. Sci Rep 2016; 6:29538. [PMID: 27383378 PMCID: PMC4935840 DOI: 10.1038/srep29538] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/20/2016] [Indexed: 12/30/2022] Open
Abstract
The inexorable decline in the armament of registered chemical insecticides has stimulated research into environmentally-friendly alternatives. Insecticidal spider-venom peptides are promising candidates for bioinsecticide development but it is challenging to find peptides that are specific for targeted pests. In the present study, we isolated an insecticidal peptide (Ae1a) from venom of the African spider Augacephalus ezendami (family Theraphosidae). Injection of Ae1a into sheep blowflies (Lucilia cuprina) induced rapid but reversible paralysis. In striking contrast, Ae1a was lethal to closely related fruit flies (Drosophila melanogaster) but induced no adverse effects in the recalcitrant lepidopteran pest Helicoverpa armigera. Electrophysiological experiments revealed that Ae1a potently inhibits the voltage-gated sodium channel BgNaV1 from the German cockroach Blattella germanica by shifting the threshold for channel activation to more depolarized potentials. In contrast, Ae1a failed to significantly affect sodium currents in dorsal unpaired median neurons from the American cockroach Periplaneta americana. We show that Ae1a interacts with the domain II voltage sensor and that sensitivity to the toxin is conferred by natural sequence variations in the S1–S2 loop of domain II. The phyletic specificity of Ae1a provides crucial information for development of sodium channel insecticides that target key insect pests without harming beneficial species.
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Affiliation(s)
- Volker Herzig
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Maria Ikonomopoulou
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jennifer J Smith
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Sławomir Dziemborowicz
- School of Medical &Molecular Biosciences, University of Technology, Sydney, NSW 2007, Australia
| | - John Gilchrist
- Department of Physiology &Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Lucia Kuhn-Nentwig
- Institute of Ecology &Evolution, University of Bern, CH 3012 Bern, Switzerland
| | | | | | - Graham M Nicholson
- School of Medical &Molecular Biosciences, University of Technology, Sydney, NSW 2007, Australia
| | - Frank Bosmans
- Department of Physiology &Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
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δ-Ctenitoxin-Pn1a, a Peptide from Phoneutria nigriventer Spider Venom, Shows Antinociceptive Effect Involving Opioid and Cannabinoid Systems, in Rats. Toxins (Basel) 2016; 8:106. [PMID: 27077886 PMCID: PMC4848632 DOI: 10.3390/toxins8040106] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/17/2016] [Accepted: 04/05/2016] [Indexed: 01/13/2023] Open
Abstract
PnTx4(6-1), henceforth renamed δ-Ctenitoxin-Pn1a (δ-CNTX-Pn1a), a peptide from Phoneutria nigriventer spider venom, initially described as an insect toxin, binds to site 3 of sodium channels in nerve cord synaptosomes and slows down sodium current inactivation in isolated axons in cockroaches (Periplaneta americana). δ-CNTX-Pn1a does not cause any apparent toxicity to mice, when intracerebroventricularly injected (30 μg). In this study, we evaluated the antinociceptive effect of δ-CNTX-Pn1a in three animal pain models and investigated its mechanism of action in acute pain. In the inflammatory pain model, induced by carrageenan, δ-CNTX-Pn1a restored the nociceptive threshold of rats, when intraplantarly injected, 2 h and 30 min after carrageenan administration. Concerning the neuropathic pain model, δ-CNTX-Pn1a, when intrathecally administered, reversed the hyperalgesia evoked by sciatic nerve constriction. In the acute pain model, induced by prostaglandin E2, intrathecal administration of δ-CNTX-Pn1a caused a dose-dependent antinociceptive effect. Using antagonists of the receptors, we showed that the antinociceptive effect of δ-CNTX-Pn1a involves both the cannabinoid system, through CB1 receptors, and the opioid system, through μ and δ receptors. Our data show, for the first time, that δ-Ctenitoxin-Pn1a is able to induce antinociception in inflammatory, neuropathic and acute pain models.
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11
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Borges MH, Figueiredo SG, Leprevost FV, De Lima ME, Cordeiro MDN, Diniz MR, Moresco J, Carvalho PC, Yates JR. Venomous extract protein profile of Brazilian tarantula Grammostola iheringi : searching for potential biotechnological applications. J Proteomics 2016; 136:35-47. [DOI: 10.1016/j.jprot.2016.01.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 12/21/2015] [Accepted: 01/25/2016] [Indexed: 02/06/2023]
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12
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Peng G, Xia Y. Expression of scorpion toxin LqhIT2 increases the virulence of Metarhizium acridum towards Locusta migratoria manilensis. J Ind Microbiol Biotechnol 2014; 41:1659-66. [PMID: 25168679 DOI: 10.1007/s10295-014-1497-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 08/12/2014] [Indexed: 01/24/2023]
Abstract
LqhIT2 is an insect-specific neurotoxin from the venom of scorpion. In this study, the LqhIT2 gene was introduced into the entomopathogenic fungus, Metarhizium acridum. The virulence of the genetically modified strain MaLqhIT2 was then evaluated against locusts (Locusta migratoria manilensis). Compared with the wild-type strain, the median lethal cell density (LC50) for MaLqhIT2 was a 22.6-fold lower, and the median times to death (LT50) for MaLqhIT2 were reduced by 30.3 and 29.6 %, respectively, after topical inoculation and injection. MaLqhIT2 also grew significantly faster in the hemolymph than wild-type strain. There were no significant differences in germination, appressorium formation and sporulation in locust carcasses between the MaLqhIT2 and wild-type strain. These results indicate that LqhIT2 increased the virulence of M. acridum towards locusts by shortening the in vivo infection period, without affecting cuticle penetration or conidia formation in the carcasses. LqhIT2 thus shows considerable potential for increasing fungal virulence against locusts.
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Affiliation(s)
- Guoxiong Peng
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, 174# shazheng st., Shangpingba District, Chongqing, 400030, China,
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13
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Ardisson-Araújo DMP, Morgado FDS, Schwartz EF, Corzo G, Ribeiro BM. A new theraphosid spider toxin causes early insect cell death by necrosis when expressed in vitro during recombinant baculovirus infection. PLoS One 2013; 8:e84404. [PMID: 24349574 PMCID: PMC3862797 DOI: 10.1371/journal.pone.0084404] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 11/20/2013] [Indexed: 11/22/2022] Open
Abstract
Baculoviruses are the most studied insect viruses in the world and are used for biological control of agricultural and forest insect pests. They are also used as versatile vectors for expression of heterologous proteins. One of the major problems of their use as biopesticides is their slow speed to kill insects. Thus, to address this shortcoming, insect-specific neurotoxins from arachnids have been introduced into the baculovirus genome solely aiming to improve its virulence. In this work, an insecticide-like toxin gene was obtained from a cDNA derived from the venom glands of the theraphosid spider Brachypelma albiceps. The mature form of the peptide toxin (called Ba3) has a high content of basic amino acid residues, potential for three possible disulfide bonds, and a predicted three-stranded β-sheetDifferent constructions of the gene were engineered for recombinant baculovirus Autographa californica multiple nuclepolyhedrovirus (AcMNPV) expression. Five different forms of Ba3 were assessed; (1) the full-length sequence, (2) the pro-peptide and mature region, (3) only the mature region, and the mature region fused to an (4) insect or a (5) virus-derived signal peptide were inserted separately into the genome of the baculovirus. All the recombinant viruses induced cell death by necrosis earlier in infection relative to a control virus lacking the toxin gene. However, the recombinant virus containing the mature portion of the toxin gene induced a faster cell death than the other recombinants. We found that the toxin construct with the signal peptide and/or pro-peptide regions delayed the necrosis phenotype. When infected cells were subjected to ultrastructural analysis, the cells showed loss of plasma membrane integrity and structural changes in mitochondria before death. Our results suggest this use of baculovirus is a potential tool to help understand or to identify the effect of insect-specific toxic peptides when produced during infection of insect cells.
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Affiliation(s)
| | | | | | - Gerardo Corzo
- Departamento de Medicina Molecular y Bioprocesos, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Bergmann Morais Ribeiro
- Departmento de Biologia Celular, Universidade de Brasília, Brasília, Brasília, DF, Brazil
- * E-mail:
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A novel ICK peptide from the Loxosceles intermedia (brown spider) venom gland: Cloning, heterologous expression and immunological cross-reactivity approaches. Toxicon 2013; 71:147-58. [DOI: 10.1016/j.toxicon.2013.05.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/10/2013] [Accepted: 05/15/2013] [Indexed: 12/28/2022]
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15
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Nunes KP, Torres FS, Borges MH, Matavel A, Pimenta AM, De Lima ME. New insights on arthropod toxins that potentiate erectile function. Toxicon 2013; 69:152-9. [DOI: 10.1016/j.toxicon.2013.03.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 02/21/2013] [Accepted: 03/22/2013] [Indexed: 12/19/2022]
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16
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Mining the virgin land of neurotoxicology: a novel paradigm of neurotoxic peptides action on glycosylated voltage-gated sodium channels. J Toxicol 2012; 2012:843787. [PMID: 22829817 PMCID: PMC3399347 DOI: 10.1155/2012/843787] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/17/2012] [Accepted: 05/24/2012] [Indexed: 12/30/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are important membrane protein carrying on the molecular basis for action potentials (AP) in neuronal firings. Even though the structure-function studies were the most pursued spots, the posttranslation modification processes, such as glycosylation, phosphorylation, and alternative splicing associating with channel functions captured less eyesights. The accumulative research suggested an interaction between the sialic acids chains and ion-permeable pores, giving rise to subtle but significant impacts on channel gating. Sodium channel-specific neurotoxic toxins, a family of long-chain polypeptides originated from venomous animals, are found to potentially share the binding sites adjacent to glycosylated region on VGSCs. Thus, an interaction between toxin and glycosylated VGSC might hopefully join the campaign to approach the role of glycosylation in modulating VGSCs-involved neuronal network activity. This paper will cover the state-of-the-art advances of researches on glycosylation-mediated VGSCs function and the possible underlying mechanisms of interactions between toxin and glycosylated VGSCs, which may therefore, fulfill the knowledge in identifying the pharmacological targets and therapeutic values of VGSCs.
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Nervous System of Periplaneta americana Cockroach as a Model in Toxinological Studies: A Short Historical and Actual View. J Toxicol 2012; 2012:143740. [PMID: 22666245 PMCID: PMC3361271 DOI: 10.1155/2012/143740] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 03/01/2012] [Indexed: 11/17/2022] Open
Abstract
Nervous system of Periplaneta americana cockroach is used in a wide range of pharmacological studies, including electrophysiological techniques. This paper presents its role as a preparation in the development of toxinological studies in the following electrophysiological methods: double-oil-gap technique on isolated giant axon, patch-clamp on DUM (dorsal unpaired median) neurons, microelectrode technique in situ conditions on axon in connective and DUM neurons in ganglion, and single-fiber oil-gap technique on last abdominal ganglion synapse. At the end the application of cockroach synaptosomal preparation is mentioned.
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Quintero-Hernández V, Ortiz E, Rendón-Anaya M, Schwartz EF, Becerril B, Corzo G, Possani LD. Scorpion and spider venom peptides: gene cloning and peptide expression. Toxicon 2011; 58:644-63. [PMID: 21978889 DOI: 10.1016/j.toxicon.2011.09.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 09/08/2011] [Accepted: 09/22/2011] [Indexed: 01/05/2023]
Abstract
This communication reviews most of the important findings related to venom components isolated from scorpions and spiders, mainly by means of gene cloning and expression. Rather than revising results obtained by classical biochemical studies that report structure and function of venom components, here the emphasis is placed on cloning and identification of genes present in the venomous glands of these arachnids. Aspects related to cDNA library construction, specific or random ESTs cloning, transcriptome analysis, high-throughput screening, heterologous expression and folding are briefly discussed, showing some numbers of species and components already identified, but also shortly mentioning limitations and perspectives of research for the future in this field.
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Affiliation(s)
- V Quintero-Hernández
- Instituto de Biotecnología - UNAM, Avenida Universidad, Colonia Chamilpa, Cuernavaca, Morelos, Mexico
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Solution structure of a short-chain insecticidal toxin LaIT1 from the venom of scorpion Liocheles australasiae. Biochem Biophys Res Commun 2011; 411:738-44. [DOI: 10.1016/j.bbrc.2011.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Accepted: 07/06/2011] [Indexed: 01/22/2023]
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20
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Exploring the obscure profiles of pharmacological binding sites on voltage-gated sodium channels by BmK neurotoxins. Protein Cell 2011; 2:437-44. [PMID: 21748593 DOI: 10.1007/s13238-011-1064-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 06/08/2011] [Indexed: 10/18/2022] Open
Abstract
Diverse subtypes of voltage-gated sodium channels (VGSCs) have been found throughout tissues of the brain, muscles and the heart. Neurotoxins extracted from the venom of the Asian scorpion Buthus martensi Karsch (BmK) act as sodium channel-specific modulators and have therefore been widely used to study VGSCs. α-type neurotoxins, named BmK I, BmK αIV and BmK abT, bind to receptor site-3 on VGSCs and can strongly prolong the inactivation phase of VGSCs. In contrast, β-type neurotoxins, named BmK AS, BmK AS-1, BmK IT and BmK IT2, occupy receptor site-4 on VGSCs and can suppress peak currents and hyperpolarize the activation kinetics of sodium channels. Accumulating evidence from binding assays of scorpion neurotoxins on VGSCs, however, indicate that pharmacological sensitivity of VGSC subtypes to different modulators is much more complex than that suggested by the simple α-type and β-type neurotoxin distinction. Exploring the mechanisms of possible dynamic interactions between site 3-/4-specific modulators and region- and/or species-specific subtypes of VGSCs would therefore greatly expand our understanding of the physiological and pharmacological properties of diverse VGSCs. In this review, we discuss the pharmacological and structural diversity of VGSCs as revealed by studies exploring the binding properties and cross-competitive binding of site 3- or site 4-specific modulators in VGSC subtypes in synaptosomes from distinct tissues of diverse species.
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Chaim OM, Trevisan-Silva D, Chaves-Moreira D, Wille ACM, Ferrer VP, Matsubara FH, Mangili OC, da Silveira RB, Gremski LH, Gremski W, Senff-Ribeiro A, Veiga SS. Brown spider (Loxosceles genus) venom toxins: tools for biological purposes. Toxins (Basel) 2011; 3:309-44. [PMID: 22069711 PMCID: PMC3202818 DOI: 10.3390/toxins3030309] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/26/2011] [Accepted: 03/17/2011] [Indexed: 12/16/2022] Open
Abstract
Venomous animals use their venoms as tools for defense or predation. These venoms are complex mixtures, mainly enriched of proteic toxins or peptides with several, and different, biological activities. In general, spider venom is rich in biologically active molecules that are useful in experimental protocols for pharmacology, biochemistry, cell biology and immunology, as well as putative tools for biotechnology and industries. Spider venoms have recently garnered much attention from several research groups worldwide. Brown spider (Loxosceles genus) venom is enriched in low molecular mass proteins (5–40 kDa). Although their venom is produced in minute volumes (a few microliters), and contain only tens of micrograms of protein, the use of techniques based on molecular biology and proteomic analysis has afforded rational projects in the area and permitted the discovery and identification of a great number of novel toxins. The brown spider phospholipase-D family is undoubtedly the most investigated and characterized, although other important toxins, such as low molecular mass insecticidal peptides, metalloproteases and hyaluronidases have also been identified and featured in literature. The molecular pathways of the action of these toxins have been reported and brought new insights in the field of biotechnology. Herein, we shall see how recent reports describing discoveries in the area of brown spider venom have expanded biotechnological uses of molecules identified in these venoms, with special emphasis on the construction of a cDNA library for venom glands, transcriptome analysis, proteomic projects, recombinant expression of different proteic toxins, and finally structural descriptions based on crystallography of toxins.
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Affiliation(s)
- Olga Meiri Chaim
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
| | - Dilza Trevisan-Silva
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
| | - Daniele Chaves-Moreira
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
| | - Ana Carolina M. Wille
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
- Department of Structural, Molecular Biology and Genetics, State University of Ponta Grossa, CEP 84030-900 Ponta Grossa, Paraná, Brazil;
| | - Valéria Pereira Ferrer
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
| | - Fernando Hitomi Matsubara
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
| | | | - Rafael Bertoni da Silveira
- Department of Structural, Molecular Biology and Genetics, State University of Ponta Grossa, CEP 84030-900 Ponta Grossa, Paraná, Brazil;
| | - Luiza Helena Gremski
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
| | - Waldemiro Gremski
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
- Catholic University of Paraná, Health and Biological Sciences Institute, CEP 80215-901 Curitiba, Paraná, Brazil;
| | - Andrea Senff-Ribeiro
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
| | - Silvio Sanches Veiga
- Department of Cell Biology, Federal University of Paraná, CEP 81531-980 Curitiba, Paraná, Brazil; (O.M.C.); (D.T.-S); (D.C.-M); (A.C.M.W.); (V.P.F.); (F.H.M.); (L.H.G.); (A.S.-R)
- Author to whom correspondence should be addressed; ; Tel.: +55-41-33611776; Fax: +55-41-3266-2042
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He H, Liu Z, Dong B, Zhang J, Shu X, Zhou J, Ji Y. Localization of receptor site on insect sodium channel for depressant β-toxin BmK IT2. PLoS One 2011; 6:e14510. [PMID: 21264295 PMCID: PMC3021515 DOI: 10.1371/journal.pone.0014510] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 12/05/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND BmK IT2 is regarded as a receptor site-4 modulator of sodium channels with depressant insect toxicity. It also displays anti-nociceptive and anti-convulsant activities in rat models. In this study, the potency and efficacy of BmK IT2 were for the first time assessed and compared among four sodium channel isoforms expressed in Xenopus oocytes. Combined with molecular approach, the receptor site of BmK IT2 was further localized. PRINCIPAL FINDINGS 2 µM BmK IT2 strongly shifted the activation of DmNa(v)1, the sodium channel from Drosophila, to more hyperpolarized potentials; whereas it hardly affected the gating properties of rNa(v)1.2, rNa(v)1.3 and mNa(v)1.6, three mammalian central neuronal sodium channel subtypes. (1) Mutations of Glu(896), Leu(899), Gly(904) in extracellular loop Domain II S3-S4 of DmNa(v)1 abolished the functional action of BmK IT2. (2) BmK IT2-preference for DmNa(v)1 could be conferred by Domain III. Analysis of subsequent DmNa(v)1 mutants highlighted the residues in Domain III pore loop, esp. Ile(1529) was critical for recognition and binding of BmK IT2. CONCLUSIONS/SIGNIFICANCE In this study, BmK IT2 displayed total insect-selectivity. Two binding regions, comprising domains II and III of DmNa(v)1, play separated but indispensable roles in the interaction with BmK IT2. The insensitivity of Na(v)1.2, Na(v)1.3 and Na(v)1.6 to BmK IT2 suggests other isoforms or mechanism might be involved in the suppressive activity of BmK IT2 in rat pathological models.
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Affiliation(s)
- Huiqiong He
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
- Graduate School of Chinese Academy of Sciences, Shanghai Institute of Physiology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Zhirui Liu
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - Bangqian Dong
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - Jianwei Zhang
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - Xueqin Shu
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - Jingjing Zhou
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - Yonghua Ji
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
- * E-mail:
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Torres F, Silva C, Lanza L, Santos AV, Pimenta A, De Lima M, Diniz M. Functional expression of a recombinant toxin – rPnTx2-6 – active in erectile function in rat. Toxicon 2010; 56:1172-80. [DOI: 10.1016/j.toxicon.2010.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2009] [Revised: 03/24/2010] [Accepted: 04/19/2010] [Indexed: 10/19/2022]
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Nunes KP, Cordeiro MN, Richardson M, Borges MN, Diniz SOF, Cardoso VN, Tostes R, De Lima ME, Webb RC, Leite R. Nitric oxide-induced vasorelaxation in response to PnTx2-6 toxin from Phoneutria nigriventer spider in rat cavernosal tissue. J Sex Med 2010; 7:3879-88. [PMID: 20722794 DOI: 10.1111/j.1743-6109.2010.01978.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Priapism is one of several symptoms observed in accidental bites by the spider Phoneutria nigriventer. The venom of this spider is comprised of many toxins, and the majority has been shown to affect excitable ion channels, mainly sodium (Na(+) ) channels. It has been demonstrated that PnTx2-6, a peptide extracted from the venom of P. nigriventer, causes erection in anesthetized rats and mice. AIM We investigated the mechanism by which PnTx2-6 evokes relaxation in rat corpus cavernosum. MAIN OUTCOME MEASURES PnTx2-6 toxin potentiates nitric oxide (NO)-dependent cavernosal relaxation. METHODS Rat cavernosal strips were incubated with bretylium (3 × 10(-5) M) and contracted with phenylephrine (PE; 10(-5) M). Relaxation responses were evoked by electrical field stimulation (EFS) or sodium nitroprusside (SNP) before and after 4 minutes of incubation with PnTx2-6 (10(-8) M). The effect of PnTx2-6 on relaxation induced by EFS was also tested in the presence of atropine (10(-6) M), a muscarinic receptor antagonist, N-type Ca(2+) channel blockers (ω-conotoxin GVIA, 10(-6) M) and sildenafil (3 × 10(-8) M). Technetium99m radiolabeled PnTx2-6 subcutaneous injection was administrated in the penis. RESULTS Whereas relaxation induced by SNP was not affected by PnTx2-6, EFS-induced relaxation was significantly potentiated by this toxin as well as PnTx2-6 plus SNP. This potentiating effect was further increased by sildenafil, not altered by atropine, however was completely blocked by the N-type Ca(2+) channels. High concentrated levels of radiolabeled PnTx2-6 was specifically found in the cavernosum tissue, suggesting PnTx2-6 is an important toxin responsible for P. nigriventer spider accident-induced priapism. CONCLUSION We show that PnTx2-6 slows Na(+) channels inactivation in nitrergic neurons, allowing Ca(2+) influx to facilitate NO/cGMP signalling, which promotes increased NO production. In addition, this relaxation effect is independent of phosphodiesterase enzyme type 5 inhibition. Our data displays PnTx2-6 as possible pharmacological tool to study alternative treatments for erectile dysfunction.
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Affiliation(s)
- Kenia P Nunes
- Biological Science Institute, Belo Horizonte, MG, Brazil.
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Billen B, Vassilevski A, Nikolsky A, Debaveye S, Tytgat J, Grishin E. Unique bell-shaped voltage-dependent modulation of Na+ channel gating by novel insect-selective toxins from the spider Agelena orientalis. J Biol Chem 2010; 285:18545-54. [PMID: 20385552 DOI: 10.1074/jbc.m110.125211] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Spider venoms provide a highly valuable source of peptide toxins that act on a wide diversity of membrane-bound receptors and ion channels. In this work, we report isolation, biochemical analysis, and pharmacological characterization of a novel family of spider peptide toxins, designated beta/delta-agatoxins. These toxins consist of 36-38 amino acid residues and originate from the venom of the agelenid funnel-web spider Agelena orientalis. The presented toxins show considerable amino acid sequence similarity to other known toxins such as mu-agatoxins, curtatoxins, and delta-palutoxins-IT from the related spiders Agelenopsis aperta, Hololena curta, and Paracoelotes luctuosus. beta/delta-Agatoxins modulate the insect Na(V) channel (DmNa(V)1/tipE) in a unique manner, with both the activation and inactivation processes being affected. The voltage dependence of activation is shifted toward more hyperpolarized potentials (analogous to site 4 toxins) and a non-inactivating persistent Na(+) current is induced (site 3-like action). Interestingly, both effects take place in a voltage-dependent manner, producing a bell-shaped curve between -80 and 0 mV, and they are absent in mammalian Na(V) channels. To the best of our knowledge, this is the first detailed report of peptide toxins with such a peculiar pharmacological behavior, clearly indicating that traditional classification of toxins according to their binding sites may not be as exclusive as previously assumed.
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Affiliation(s)
- Bert Billen
- Laboratory of Toxicology, University of Leuven, KU Leuven, Campus Gasthuisberg O&N2, Herestraat 49, PO Box 922, B-3000 Leuven, Belgium
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Hyper-excitability in low threshold mechanical A fibers is potentially involved in scorpion BmK sting pain. Brain Res Bull 2009; 80:116-21. [PMID: 19393723 DOI: 10.1016/j.brainresbull.2009.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 04/13/2009] [Accepted: 04/14/2009] [Indexed: 01/28/2023]
Abstract
In the present study, using the single fiber recording technique, we found that BmK I, the main toxic component in scorpion Buthus martensi Karsch (BmK) venom, induced dramatic increase in excitability of rapidly adapting (RA) and type I slowly adapting (SAI) low threshold mechanical A fibers of rat. Five micrograms BmK I (691 nmol, in 10 microl saline) administrated to the receptive fields induced spontaneous activity in 80% of RA and SAI fibers, increased the response to 10 g-10 s stimulation at about 20 times and altered the firing pattern to burst mode with maximal NS (number of spikes in burst) averaging from all fibers studied as many as 59. The increase in the excitability of RA and SAI fibers did not recover completely in 2h. Our finding suggests that the gigantic abnormal activity in low threshold mechanical A fibers is involved in BmK scorpion sting pain, and the experimental model of BmK scorpion sting pain can be used to study A-fiber related central pathway which is important for relief of refractory neuropathic pain likewise.
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Tityus serrulatus venom peptidomics: Assessing venom peptide diversity. Toxicon 2008; 52:611-8. [DOI: 10.1016/j.toxicon.2008.07.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 07/17/2008] [Accepted: 07/22/2008] [Indexed: 11/23/2022]
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28
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Nunes KP, Costa-Gonçalves A, Lanza LF, Cortes SF, Cordeiro MN, Richardson M, Pimenta AMC, Webb RC, Leite R, De Lima ME. Tx2-6 toxin of the Phoneutria nigriventer spider potentiates rat erectile function. Toxicon 2008; 51:1197-206. [PMID: 18397797 DOI: 10.1016/j.toxicon.2008.02.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 02/07/2008] [Accepted: 02/08/2008] [Indexed: 11/26/2022]
Abstract
The venom of the spider Phoneutria nigriventer contains several toxins that have bioactivity in mammals and insects. Accidents involving humans are characterized by various symptoms including penile erection. Here we investigated the action of Tx2-6, a toxin purified from the P. nigriventer spider venom that causes priapism in rats and mice. Erectile function was evaluated through changes in intracavernosal pressure/mean arterial pressure ratio (ICP/MAP) during electrical stimulation of the major pelvic ganglion (MPG) of normotensive and deoxycorticosterone-acetate (DOCA)-salt hypertensive rats. Nitric oxide (NO) release was detected in cavernosum slices with fluorescent dye (DAF-FM) and confocal microscopy. The effect of Tx2-6 was also characterized after intracavernosal injection of a non-selective nitric oxide synthase (NOS) inhibitor, L-NAME. Subcutaneous or intravenous injection of Tx2-6 potentiated the elevation of ICP/MAP induced by ganglionic stimulation. L-NAME inhibited penile erection and treatment with Tx2-6 was unable to reverse this inhibition. Tx2-6 treatment induced a significant increase of NO release in cavernosum tissue. Attenuated erectile function of DOCA-salt hypertensive rats was fully restored after toxin injection. Tx2-6 enhanced erectile function in normotensive and DOCA-salt hypertensive rats, via the NO pathway. Our studies suggest that Tx2-6 could be important for development of new pharmacological agents for treatment of erectile dysfunction.
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Affiliation(s)
- K P Nunes
- Departamento de Fisiologia e Biofisica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais , Belo Horizonte, Minas Gerais, Brazil
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