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A subfraction obtained from the venom of the tarantula Poecilotheria regalis contains inhibitor cystine knot peptides and induces relaxation of rat aorta by inhibiting L-type voltage-gated calcium channels. Toxicon X 2023; 18:100151. [PMID: 36873112 PMCID: PMC9978846 DOI: 10.1016/j.toxcx.2023.100151] [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: 12/20/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/19/2023] Open
Abstract
Venoms from tarantulas contain low molecular weight vasodilatory compounds whose biological action is conceived as part of the envenomation strategy due to its propagative effects. However, some properties of venom-induced vasodilation do not match those described by such compounds, suggesting that other toxins may cooperate with these ones to produce the observed biological effect. Owing to the distribution and function of voltage-gated ion channels in blood vessels, disulfide-rich peptides isolated from venoms of tarantulas could be conceived into potential vasodilatory compounds. However, only two peptides isolated from spider venoms have been investigated so far. This study describes for the first time a subfraction containing inhibitor cystine knot peptides, PrFr-I, obtained from the venom of the tarantula Poecilotheria regalis. This subfraction induced sustained vasodilation in rat aortic rings independent of vascular endothelium and endothelial ion channels. Furthermore, PrFr-I decreased calcium-induced contraction of rat aortic segments and reduced extracellular calcium influx to chromaffin cells by the blockade of L-type voltage-gated calcium channels. This mechanism was unrelated to the activation of potassium channels from vascular smooth muscle, since vasodilation was not affected in the presence of TEA, and PrFr-I did not modify the conductance of the voltage-gated potassium channel Kv10.1. This work proposes a new envenomating function of peptides from venoms of tarantulas, and establishes a new mechanism for venom-induced vasodilation.
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Key Words
- ACh, acetylcholine
- ADP, adenosine diphosphate
- Cav, voltage-gated calcium channel
- DMEM, Dulbecco's modified eagle's medium
- DRP, disulfide-rich peptide
- EC50, half maximal effective concentration
- Emax, maximum effect
- FBS, fetal bovine serum
- HPLC, high-performance liquid chromatography
- ICK peptide
- ICK, inhibitor cystine knot
- IKCa, intermediate conductance calcium-activated potassium channel
- Kv, voltage-gated potassium channel
- L-type calcium voltage-gated calcium
- LC-MS/MS, liquid chromatography-tandem mass spectrometer
- MALDI, matrix-assisted desorption ionization
- Nav, voltage-gated sodium channel
- Phe, phenylephrine
- Poecilotheria regalis, venom
- RP, reverse phase
- Rat aorta
- SEM, standard error of the mean
- SKCa, small conductance calcium-activated potassium channel
- SNP, sodium nitroprusside
- TEA, tetraethylammonium
- TOF, time of flight
- TRP, transient receptor potential
- Vasodilation
- Vh, holding-voltage
- endothelium-intact (E+), endothelium-denuded (E−)
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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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Fernandes FF, Moraes JR, Santos JLD, Soares TG, Gouveia VJP, Matavel ACS, Borges WDC, Cordeiro MDN, Figueiredo SG, Borges MH. Comparative venomic profiles of three spiders of the genus Phoneutria. J Venom Anim Toxins Incl Trop Dis 2022; 28:e20210042. [PMID: 35283937 PMCID: PMC8875809 DOI: 10.1590/1678-9199-jvatitd-2021-0042] [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: 04/05/2021] [Accepted: 07/20/2021] [Indexed: 11/22/2022] Open
Abstract
Background: Spider venoms induce different physio-pharmacological effects by binding
with high affinity on molecular targets, therefore being of biotechnological
interest. Some of these toxins, acting on different types of ion channels,
have been identified in the venom of spiders of the genus
Phoneutria, mainly from P.
nigriventer. In spite of the pharmaceutical potential demonstrated
by P. nigriventer toxins, there is limited information on
molecules from venoms of the same genus, as their toxins remain poorly
characterized. Understanding this diversity and clarifying the differences
in the mechanisms of action of spider toxins is of great importance for
establishing their true biotechnological potential. This prompted us to
compare three different venoms of the Phoneutria genus:
P. nigriventer (Pn-V), P. eickstedtae
(Pe-V) and P. pertyi (Pp-V). Methods: Biochemical and functional comparison of the venoms were carried out by
SDS-PAGE, HPLC, mass spectrometry, enzymatic activities and
electrophysiological assays (whole-cell patch clamp). Results: The employed approach revealed that all three venoms had an overall
similarity in their components, with only minor differences. The presence of
a high number of similar proteins was evident, particularly toxins in the
mass range of ~6.0 kDa. Hyaluronidase and proteolytic activities were
detected in all venoms, in addition to isoforms of the toxins Tx1 and Tx2-6.
All Tx1 isoforms blocked Nav1.6 ion currents, with slight differences. Conclusion: Our findings showed that Pn-V, Pe-V and Pp-V are highly similar concerning
protein composition and enzymatic activities, containing isoforms of the
same toxins sharing high sequence homology, with minor modifications.
However, these structural and functional variations are very important for
venom diversity. In addition, our findings will contribute to the
comprehension of the molecular diversity of the venoms of the other species
from Phoneutria genus, exposing their biotechnological
potential as a source for searching for new active molecules.
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The synthetic peptide PnPP-19 potentiates erectile function via nNOS and iNOS. Nitric Oxide 2021; 113-114:23-30. [PMID: 33915274 DOI: 10.1016/j.niox.2021.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 01/27/2023]
Abstract
PnPP-19 peptide has a primary sequence design based on molecular modeling studies of PnTx2-6 toxin. It comprises the amino acid residues that are potentially significant for the pharmacological action of PnTx2-6. Ex vivo and in vivo experiments in normotensive, hypertensive, or diabetic murine models have shown a significant improvement in penile erection after administration of PnPP-19. Given the potential use of PnPP-19 in pharmaceutical formulations to treat erectile dysfunction and the lack of information concerning its mode of action, the present work investigates its activities on the nitrergic system. PnPP-19 induced a significant increase in nitric oxide (NO) and cGMP levels in corpus cavernosum (cc). These effects were inhibited by l-NAME, a non-selective inhibitor of nitric oxide synthase (NOS); were partially inhibited by 7- Nitroindazole, a selective inhibitor of neuronal NOS (nNOS); and were abolished by L-NIL, a selective inhibitor of inducible NOS (iNOS). This potentiating effect was not affected by atropine. PnPP-19 also led to changes in mRNA levels, protein expression and phosphorylation at specific sites of NOS, in cc. Assays using cavernous tissue from knockout mice to endothelial NOS (eNOS), nNOS or iNOS showed that PnPP-19 potentiates relaxation only in eNOS-knockout mice, which suggests an essential role for nNOS. Surprisingly, iNOS enhanced the potentiation of erectile function evoked by PnPP-19. Our results demonstrate that this new synthetic peptide potentiates erectile function via nitric oxide activation and reinforce its role as a new pharmacological tool for the treatment of erectile dysfunction.
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Senthilkumaran S, Williams HF, Patel K, Trim SA, Thirumalaikolundusubramanian P, Vaiyapuri S. Priapism following a juvenile Russell's viper bite: An unusual case report. PLoS Negl Trop Dis 2021; 15:e0009242. [PMID: 33764978 PMCID: PMC7993604 DOI: 10.1371/journal.pntd.0009242] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Following a bite from a juvenile Russell's viper (Daboia russelii), a priapism (painful erection) developed rapidly in a 16-year-old male and only subsided after administration of antivenom 3 hours later. Potential mechanisms for this snakebite-induced priapism are unclear but likely due to venom toxins causing nitric oxide (NO) release and subsequent vasodilation of endothelium in the corpus cavernosum, although the possible involvement of other mechanisms cannot be ruled out. We strongly believe that this unusual case report may lead to further scientific research in order to improve the clinical understanding of the pathophysiology of envenomation due to Russell's viper bites. Although it is too early to speculate, further research may also discover the possibilities of developing venom-based candidate molecules to treat sexual dysfunction in males and females.
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Affiliation(s)
| | | | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading, United Kingdom
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6
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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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Peigneur S, Paiva ALB, Cordeiro MN, Borges MH, Diniz MRV, de Lima ME, Tytgat J. Phoneutria nigriventer Spider Toxin PnTx2-1 (δ-Ctenitoxin-Pn1a) Is a Modulator of Sodium Channel Gating. Toxins (Basel) 2018; 10:toxins10090337. [PMID: 30134593 PMCID: PMC6162791 DOI: 10.3390/toxins10090337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 01/31/2023] Open
Abstract
Spider venoms are complex mixtures of biologically active components with potentially interesting applications for drug discovery or for agricultural purposes. The spider Phoneutria nigriventer is responsible for a number of envenomations with sometimes severe clinical manifestations in humans. A more efficient treatment requires a comprehensive knowledge of the venom composition and of the action mechanism of the constituting components. PnTx2-1 (also called δ-ctenitoxin-Pn1a) is a 53-amino-acid-residue peptide isolated from the venom fraction PhTx2. Although PnTx2-1 is classified as a neurotoxin, its molecular target has remained unknown. This study describes the electrophysiological characterization of PnTx2-1 as a modulator of voltage-gated sodium channels. PnTx2-1 is investigated for its activity on seven mammalian NaV-channel isoforms, one insect NaV channel and one arachnid NaV channel. Furthermore, comparison of the activity of both PnTx2-1 and PnTx2-6 on NaV1.5 channels reveals that this family of Phoneutria toxins modulates the cardiac NaV channel in a bifunctional manner, resulting in an alteration of the inactivation process and a reduction of the sodium peak current.
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Affiliation(s)
- Steve Peigneur
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg, P.O. Box 922, Herestraat 49, 3000 Leuven, Belgium.
- Laboratório de Venenos e Toxinas Animais, Dept de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte 31270-901, Brazil.
| | - Ana Luiza B Paiva
- Departamento de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Minas Gerais, Belo Horizonte 30510-010, Brazil.
| | - Marta N Cordeiro
- Departamento de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Minas Gerais, Belo Horizonte 30510-010, Brazil.
| | - Márcia H Borges
- Departamento de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Minas Gerais, Belo Horizonte 30510-010, Brazil.
| | - Marcelo R V Diniz
- Departamento de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Minas Gerais, Belo Horizonte 30510-010, Brazil.
| | - Maria Elena de Lima
- Laboratório de Venenos e Toxinas Animais, Dept de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte 31270-901, Brazil.
- Programa de Pós-graduação em Ciências da Saúde, Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte, Grupo Santa Casa de Belo Horizonte, Minas Gerais, Belo Horizonte 31270-901, Brazil.
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg, P.O. Box 922, Herestraat 49, 3000 Leuven, Belgium.
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8
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PnTx2-6 (or δ-CNTX-Pn2a), a toxin from Phoneutria nigriventer spider venom, releases l-glutamate from rat brain synaptosomes involving Na+ and Ca2+ channels and changes protein expression at the blood-brain barrier. Toxicon 2018; 150:280-288. [DOI: 10.1016/j.toxicon.2018.06.073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/12/2018] [Accepted: 06/14/2018] [Indexed: 11/18/2022]
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9
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Ma B, Xi Z, Li J, Gao T, Liao R, Wang S, Li X, Tang Y, Wang Z, Hou S, Jiang J, Deng M, Duan Z, Tang X, Jiang L. Vasodilator and hypotensive effects of the spider peptide Lycosin-I in vitro and in vivo. Peptides 2018; 99:108-114. [PMID: 29248696 DOI: 10.1016/j.peptides.2017.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/11/2017] [Accepted: 12/12/2017] [Indexed: 11/23/2022]
Abstract
Lycosin-I, a spider peptide isolated from the venom of the spider Lycosa singoriensis, has anti-bacteria and anti-cancer properties in organisms. However, cardiovascular effects of Lycosin-I have not been studied. In this study, we investigated for the first time the vasodilator and hypotensive effects of Lycosin-I and the possible mechanisms, in order to develop a promising treatment for hypertension-related diseases. For in vitro experiments, thoracic aortas were isolated, and divided into two groups, endothelium-intact and endothelium-denuded aortic rings. Lycosin-I induced a remarkable dose-dependent relaxation in endothelium-intact aortic rings pre-treated with phenylephrine (p < 0.05), while it showed no obvious vasodilator effects in endothelium-denuded aortic rings (p > 0.05). The vasodilator effects of Lycosin-I were significantly weakened by a nitric oxide synthase (NOS) inhibitor, L-NAME (p < 0.001) and a selective inhibitor of nitric oxide (NO)-sensitive soluble guanylate cyclase (sGC), ODQ (p < 0.05), respectively. The levels of endothelial nitric oxide synthase (eNOS) phosphorylation and the NO production were significantly higher in human umbilical vascular endothelial cells pre-cultured with Lycosin-I than the control (p < 0.001), determined via western blot analysis and ozone-chemiluminescence technology. For in vivo experiments, arterial and venous catheters were inserted for mean arterial pressure (MAP) recording and drug administration in anaesthetized spontaneously hypertensive rats. Lycosin-I caused a transient drop of MAP 2 min after the administration compared with the control (p < 0.001). In conclusion, Lycosin-I has the potential to be an anti-hypertensive drug by endothelium-dependent vasodilatation, in which eNOS and NO-sensitive sGC are two main involved factors.
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Affiliation(s)
- Binbin Ma
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Zhouhuan Xi
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Jiahui Li
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Tianqi Gao
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Runzhi Liao
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Shuhang Wang
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Xianyao Li
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Yaqin Tang
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Zheng Wang
- The First Department of General Surgery, the Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, PR China
| | - Shengjie Hou
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Jinying Jiang
- Department of Neonatology, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410013, PR China
| | - Meichun Deng
- Department of Biochemistry, School of Life Sciences, Central South University, Changsha, Hunan 410013, PR China
| | - Zhigui Duan
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, PR China
| | - Xing Tang
- College of Chemistry, Biology, and Material Science, East China Institute of Technology, Nanchang, Jiangxi 330013, PR China
| | - Liping Jiang
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China.
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Silva CN, Nunes KP, Torres FS, Cassoli JS, Santos DM, Almeida FDM, Matavel A, Cruz JS, Santos-Miranda A, Nunes ADC, Castro CH, Machado de Ávila RA, Chávez-Olórtegui C, Láuar SS, Felicori L, Resende JM, Camargos ERDS, Borges MH, Cordeiro MN, Peigneur S, Tytgat J, de Lima ME. PnPP-19, a Synthetic and Nontoxic Peptide Designed from a Phoneutria nigriventer Toxin, Potentiates Erectile Function via NO/cGMP. J Urol 2015; 194:1481-90. [PMID: 26119670 DOI: 10.1016/j.juro.2015.06.081] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2015] [Indexed: 01/09/2023]
Abstract
PURPOSE We designed a peptide, PnPP-19, comprising the potential active core of the Phoneutria nigriventer native toxin PnTx2-6. We investigated its role on erectile function, and its toxicity and immunogenicity. MATERIALS AND METHODS Erectile function was evaluated by the intracavernous pressure-to-mean arterial pressure ratio during electrical field stimulation on rat pelvic ganglia. Cavernous strips were contracted with phenylephrine and relaxation was induced by electrical field stimulation with or without PnPP-19 (10(-8) M). Activity on sodium channels was evaluated by electrophysiological screening of transfected channels on Xenopus oocytes and dorsal root ganglion cells. Antibodies were detected by indirect enzyme-linked immunosorbent assay in mice previously treated with the peptide. Histopathological studies were performed with mouse organs treated with different doses of PnPP-19. RESULTS PnPP-19 was able to potentiate erection at 4 and 8 Hz in vivo and ex vivo. It showed no toxicity and low immunogenicity in mice, and did not affect sodium channels or rat hearts. PnPP-19 increased cyclic guanosine monophosphate levels at 8 Hz. This effect was inhibited by L-NAME (10(-4) M). Erectile function was partially inhibited by 7-nitroindazole (10(-5) M), a selective inhibitor of neuronal nitric oxide synthase. CONCLUSIONS PnPP-19 potentiates erection in vivo and ex vivo via the nitric oxide/cyclic guanosine monophosphate pathway. It does not affect sodium channels or rat hearts and shows no toxicity and low immunogenicity. These findings make it a promising candidate as a novel drug in the therapy of erectile dysfunction.
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Affiliation(s)
- Carolina Nunes Silva
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Kenia Pedrosa Nunes
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Fernanda Silva Torres
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Juliana Silva Cassoli
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniel Moreira Santos
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Flávia De Marco Almeida
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Jader Santos Cruz
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Arthur Santos-Miranda
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | | | | | - Carlos Chávez-Olórtegui
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Stephanie Stransky Láuar
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Liza Felicori
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | | | | | | | - Steve Peigneur
- Toxicology and Pharmacology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Maria Elena de Lima
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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11
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Decaluwé K, Pauwels B, Boydens C, Van de Voorde J. Treatment of erectile dysfunction: new targets and strategies from recent research. Pharmacol Biochem Behav 2013; 121:146-57. [PMID: 24291648 DOI: 10.1016/j.pbb.2013.11.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/18/2013] [Indexed: 12/15/2022]
Abstract
In recent years, research on penile erection has increasingly been centered on the molecular mechanisms involved. Major progress has been made in the field and at present a whole number of neurotransmitters, chemical effectors, growth factors, second-messenger molecules, ions, intercellular proteins, and hormones have been characterized as components of the complex process of erection. This knowledge has led to the discovery of several new therapeutic targets and multiple medical approaches for the treatment of erectile dysfunction (ED). This review focuses on the progress made in this field within the last few years.
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Affiliation(s)
- K Decaluwé
- Department of Pharmacology, Ghent University, Ghent, Belgium
| | - B Pauwels
- Department of Pharmacology, Ghent University, Ghent, Belgium
| | - C Boydens
- Department of Pharmacology, Ghent University, Ghent, Belgium
| | - J Van de Voorde
- Department of Pharmacology, Ghent University, Ghent, Belgium.
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12
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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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Nunes KP, Toque HA, Borges MH, Richardson M, Webb RC, de Lima ME. Erectile function is improved in aged rats by PnTx2-6, a toxin from Phoneutria nigriventer spider venom. J Sex Med 2012; 9:2574-81. [PMID: 22925420 DOI: 10.1111/j.1743-6109.2012.02878.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Age-associated erectile dysfunction (ED) involves a decrease in nitric oxide (NO) availability and impaired relaxation. PnTx2-6, a toxin from the Phoneutria nigriventer spider, has been demonstrated to improve erectile function via NO/cyclic guanosine monophosphate (cGMP) pathway. This spider's venom is characterized by several symptoms, including erection. PnTx2-6 has been implicated in this phenomenon. Animal venoms have been postulated as potential drugs to treat ED. AIM PnTx2-6 toxin improves erectile function in aged rats via NO/cGMP. We investigated the effect of PnTx2-6 in the erectile function of aged rats. MAIN OUTCOME MEASURES ED was evaluated through changes in intracavernosal pressure/mean arterial pressure ratio during electrical field stimulation (EFS) of the pelvic ganglion of aged and adult rats (70 vs. 14 weeks). In functional studies, EFS-induced relaxation of corpus cavernosum (CC) strips were performed with or without PnTx2-6 (10-8M). RESULTS The decrease in erectile function associated with age was partially restored 15-20 minutes after injection of PnTx2-6 and further improved by sildenafil. PnTx2-6 enhanced EFS-induced relaxation, as well as cGMP levels in CC, from young and aged rats. Relaxation due to PnTx2-6 was further increased after 30 minutes incubation with Y-27632, a Rho-kinase inhibitor (10-6 M), in aging CC. Nitric oxide synthase (NOS) activity in aged and young cavernosal tissue was increased by incubation with PnTx2-6 (10 minutes). However, this toxin did not modify NOS expression. CONCLUSION PnTx2-6 improves penile relaxation in aged rats, via increased NOS activity and NO release, resulting in enhanced cGMP levels.
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Affiliation(s)
- Kenia P Nunes
- Department of Physiology, Georgia Health Sciences University, Augusta, GA, USA.
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Nunes KP, Wynne BM, Cordeiro MN, Borges MH, Richardson M, Leite R, DeLima ME, Webb RC. Increased cavernosal relaxation by Phoneutria nigriventer toxin, PnTx2-6, via activation at NO/cGMP signaling. Int J Impot Res 2011; 24:69-76. [PMID: 21975567 PMCID: PMC3253321 DOI: 10.1038/ijir.2011.47] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Erectile dysfunction mechanisms in diabetic patients are multifactorial and often lead to resistance to current therapy. Animal toxins have been used as pharmacological tools to study penile erection. Human accidents involving the venom of Phoneutria nigriventer spider are characterized by priapism. We hypothesize that PnTx2-6 potentiates cavernosal relaxation in diabetic mice by increasing cGMP. This effect is nNOS dependent. Cavernosal strips were contracted with phenylephrine (10−5 M) and relaxed by electrical field stimulation (EFS, 20V, 1–32 Hz) in the presence or absence of PnTx2-6 (10−8 M).Cavernosal strips from nNOS and eNOS knocaut (KO) mice, besides nNOS inhibitor (10−5M), were used to evaluate the role of this enzyme in the potentiation effect evoked by PnTx2-6. Tissue cGMP levels were determined after stimulation with PnTx2-6 in presence or absence of L-NAME (10−4M) and ω-conotoxin GVIA (10−6M), an N-type calcium channel inhibitor. Results showed PnTx2-6 enhanced cavernosal relaxation in diabetic mice (65%) and eNOS KO mice, but not in nNOS KO mice. The toxin effect in the cavernosal relaxation was abolished by nNOS inhibitor. cGMP levels are increased by PnTx2-6, however L-NAME abolished this enhancement as well as ω-conotoxin GVIA. We conclude PnTx2-6 facilitates penile relaxation in diabetic mice through a mechanism dependent on nNOS, probably via increasing NO/cGMP production.
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Affiliation(s)
- K P Nunes
- Department of Biochemistry, Biological Science Institute, Federal University of Minas Gerais, Gerais, Belo Horizonte, Brazil.
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Capel RO, Mónica FZ, Porto M, Barillas S, Muscará MN, Teixeira SA, Arruda AMM, Pissinatti L, Pissinatti A, Schenka AA, Antunes E, Nahoum C, Cogo JC, de Oliveira MA, De Nucci G. Role of a novel tetrodotoxin-resistant sodium channel in the nitrergic relaxation of corpus cavernosum from the South American rattlesnake Crotalus durissus terrificus. J Sex Med 2011; 8:1616-25. [PMID: 21477017 DOI: 10.1111/j.1743-6109.2011.02246.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Coitus in snakes may last up to 28 hours; however, the mechanisms involved are unknown. AIM To evaluate the relevance of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-phosphodiesterase type 5 (PDE5) system in snake corpus cavernosum reactivity. METHODS Hemipenes were removed from anesthetized South American rattlesnakes (Crotalus durissus terrificus) and studied by light and scanning electronic microscopy. Isolated Crotalus corpora cavernosa (CCC) were dissected from the non-spiny region of the hemipenises, and tissue reactivity was assessed in organ baths. MAIN OUTCOME MEASURES Cumulative concentration-response curves were constructed for acetylcholine (ACh), sodium nitroprusside (SNP), 5-cyclopropyl-2-[1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]pyrimidin-4-ylamine (BAY 41-2272), and tadalafil in CCC precontracted with phenylephrine. Relaxation induced by electrical field stimulation (EFS) was also done in the absence and presence of N(ω) nitro-L-arginine methyl ester (L-NAME; 100 µM), 1H-[1, 2, 4] oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 µM) and tetrodotoxin (TTX; 1 µM). RESULTS The hemipenes consisted of two functionally concentric corpora cavernosa, one of them containing radiating bundles of smooth muscle fibers (confirmed by α-actin immunostaining). Endothelial and neural nitric oxide synthases were present in the endothelium and neural structures, respectively; whereas soluble guanylate cyclase and PDE5 were expressed in trabecular smooth muscle. ACh and SNP relaxed isolated CCC, with the relaxations being markedly reduced by L-NAME and ODQ, respectively. BAY 41-2272 and tadalafil caused sustained relaxations with potency (pEC(50) ) values of 5.84 ± 0.17 and 5.10 ± 0.08 (N=3-4), respectively. In precontracted CCC, EFS caused frequency-dependent relaxations that lasted three times longer than those in mammalian CC. Although these relaxations were almost abolished by either L-NAME or ODQ, they were unaffected by TTX. In contrast, EFS-induced relaxations in marmoset CC were abolished by TTX. CONCLUSIONS Rattlesnake CC relaxation is mediated by the NO-cGMP-PDE5 pathway in a manner similar to mammals. The novel TTX-resistant Na channel identified here may be responsible for the slow response of smooth muscle following nerve stimulation and could explain the extraordinary duration of snake coitus.
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Affiliation(s)
- Rodrigo O Capel
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
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