42 results on '"Dekan, Zoltan"'
Search Results
2. A tetrapeptide class of biased analgesics from an Australian fungus targets the μ-opioid receptor
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Dekan, Zoltan, Sianati, Setareh, Yousuf, Arsalan, Sutcliffe, Katy J., Gillis, Alexander, Mallet, Christophe, Singh, Paramjit, Jin, Aihua H., Wang, Anna M., Mohammadi, Sarasa A., Stewart, Michael, Ratnayake, Ranjala, Fontaine, Frank, Lacey, Ernest, Piggott, Andrew M., Du, Yan P., Canals, Meritxell, Sessions, Richard B., Kelly, Eamonn, Capon, Robert J., Alewood, Paul F., and Christ, MacDonald J.
- Published
- 2019
3. Novel Scorpion Toxin ω-Buthitoxin-Hf1a Selectively Inhibits Calcium Influx via Ca V 3.3 and Ca V 3.2 and Alleviates Allodynia in a Mouse Model of Acute Postsurgical Pain.
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Wang, Dan, Herzig, Volker, Dekan, Zoltan, Rosengren, K. Johan, Payne, Colton D., Hasan, Md. Mahadhi, Zhuang, Jiajie, Bourinet, Emmanuel, Ragnarsson, Lotten, Alewood, Paul F., and Lewis, Richard J.
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SCORPION venom ,POSTOPERATIVE pain ,AMINO acid residues ,LABORATORY mice ,PEPTIDOMIMETICS ,MEMBRANE proteins - Abstract
Venom peptides have evolved to target a wide range of membrane proteins through diverse mechanisms of action and structures, providing promising therapeutic leads for diseases, including pain, epilepsy, and cancer, as well as unique probes of ion channel structure-function. In this work, a high-throughput FLIPR window current screening assay on T-type Ca
V 3.2 guided the isolation of a novel peptide named ω-Buthitoxin-Hf1a from scorpion Hottentotta franzwerneri crude venom. At only 10 amino acid residues with one disulfide bond, it is not only the smallest venom peptide known to target T-type CaV s but also the smallest structured scorpion venom peptide yet discovered. Synthetic Hf1a peptides were prepared with C-terminal amidation (Hf1a-NH2 ) or a free C-terminus (Hf1a-OH). Electrophysiological characterization revealed Hf1a-NH2 to be a concentration-dependent partial inhibitor of CaV 3.2 (IC50 = 1.18 μM) and CaV 3.3 (IC50 = 0.49 μM) depolarized currents but was ineffective at CaV 3.1. Hf1a-OH did not show activity against any of the three T-type subtypes. Additionally, neither form showed activity against N-type CaV 2.2 or L-type calcium channels. The three-dimensional structure of Hf1a-NH2 was determined using NMR spectroscopy and used in docking studies to predict its binding site at CaV 3.2 and CaV 3.3. As both CaV 3.2 and CaV 3.3 have been implicated in peripheral pain signaling, the analgesic potential of Hf1a-NH2 was explored in vivo in a mouse model of incision-induced acute post-surgical pain. Consistent with this role, Hf1a-NH2 produced antiallodynia in both mechanical and thermal pain. [ABSTRACT FROM AUTHOR]- Published
- 2024
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4. PHAB toxins: a unique family of predatory sea anemone toxins evolving via intra-gene concerted evolution defines a new peptide fold
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Madio, Bruno, Peigneur, Steve, Chin, Yanni K. Y., Hamilton, Brett R., Henriques, Sónia Troeira, Smith, Jennifer J., Cristofori-Armstrong, Ben, Dekan, Zoltan, Boughton, Berin A., Alewood, Paul F., Tytgat, Jan, King, Glenn F., and Undheim, Eivind A. B.
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- 2018
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5. The α1-adrenoceptor inhibitor ρ-TIA facilitates net hunting in piscivorous Conus tulipa
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Dutt, Mriga, Giacomotto, Jean, Ragnarsson, Lotten, Andersson, Åsa, Brust, Andreas, Dekan, Zoltan, Alewood, Paul F., and Lewis, Richard J.
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- 2019
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6. Anti-allodynic effects of the selective NaV1.7 inhibitor Pn3a in a mouse model of acute post-surgical pain: evidence for analgesic synergy with opioids and baclofen
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Mueller, Alexander, Starobova, Hana, Morgan, Michael, Dekan, Zoltan, Cheneval, Olivier, Schroeder, Christina I., Alewood, Paul F., Deuis, Jennifer R., and Vetter, Irina
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- 2019
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7. Antiallodynic effects of the selective NaV1.7 inhibitor Pn3a in a mouse model of acute postsurgical pain: evidence for analgesic synergy with opioids and baclofen
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Mueller, Alexander, Starobova, Hana, Morgan, Michael, Dekan, Zoltan, Cheneval, Olivier, Schroeder, Christina I., Alewood, Paul F., Deuis, Jennifer R., and Vetter, Irina
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- 2019
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8. Selective spider toxins reveal a role for the Nav1.1 channel in mechanical pain
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Osteen, Jeremiah D., Herzig, Volker, Gilchrist, John, Emrick, Joshua J., Zhang, Chuchu, Wang, Xidao, Castro, Joel, Garcia-Caraballo, Sonia, Grundy, Luke, Rychkov, Grigori Y., Weyer, Andy D., Dekan, Zoltan, Undheim, Eivind A. B., Alewood, Paul, Stucky, Cheryl L., Brierley, Stuart M., Basbaum, Allan I., Bosmans, Frank, King, Glenn F., and Julius, David
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Sodium channels -- Physiological aspects ,Spider venoms -- Physiological aspects ,Nociceptors -- Physiological aspects ,Pain -- Physiological aspects ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Voltage-gated sodium (Na[sub.v]) channels initiate action potentials in most neurons, including primary afferent nerve fibres of the pain pathway. Local anaesthetics block pain through non-specific actions at all Na[sub.v] channels, but the discovery of selective modulators would facilitate the analysis of individual subtypes of these channels and their contributions to chemical, mechanical, or thermal pain. Here we identify and characterize spider (Heteroscodra maculata) toxins that selectively activate the Na[sub.v]1.1 subtype, the role of which in nociception and pain has not been elucidated. We use these probes to show that Na[sub.v]1.1-expressing fibres are modality-specific nociceptors: their activation elicits robust pain behaviours without neurogenic inflammation and produces profound hypersensitivity to mechanical, but not thermal, stimuli. In the gut, high-threshold mechanosensitive fibres also express Na[sub.v]1.1 and show enhanced toxin sensitivity in a mouse model of irritable bowel syndrome. Together, these findings establish an unexpected role for Na[sub.v]1.1 channels in regulating the excitability of sensory nerve fibres that mediate mechanical pain., Author(s): Jeremiah D. Osteen [1]; Volker Herzig [2]; John Gilchrist [3]; Joshua J. Emrick [1]; Chuchu Zhang [1]; Xidao Wang [4]; Joel Castro [5, 6]; Sonia Garcia-Caraballo [5, 6]; Luke [...]
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- 2016
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9. The Tarantula Toxin ω-Avsp1a Specifically Inhibits Human Ca V 3.1 and Ca V 3.3 via the Extracellular S3-S4 Loop of the Domain 1 Voltage-Sensor.
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Herzig, Volker, Chen, Yong-Cyuan, Chin, Yanni K.-Y., Dekan, Zoltan, Chang, Yu-Wang, Yu, Hui-Ming, Alewood, Paul F., Chen, Chien-Chang, and King, Glenn F.
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SPIDER venom ,TARANTULAS ,CALCIUM channels ,PREVENTIVE medicine ,TOXINS ,BINDING sites - Abstract
Inhibition of T-type calcium channels (Ca
V 3) prevents development of diseases related to cardiovascular and nerve systems. Further, knockout animal studies have revealed that some diseases are mediated by specific subtypes of CaV 3. However, subtype-specific CaV 3 inhibitors for therapeutic purposes or for studying the physiological roles of CaV 3 subtypes are missing. To bridge this gap, we employed our spider venom library and uncovered that Avicularia spec. ("Amazonas Purple", Peru) tarantula venom inhibited specific T-type CaV channel subtypes. By using chromatographic and mass-spectrometric techniques, we isolated and sequenced the active toxin ω-Avsp1a, a C-terminally amidated 36 residue peptide with a molecular weight of 4224.91 Da, which comprised the major peak in the venom. Both native (4.1 μM) and synthetic ω-Avsp1a (10 μM) inhibited 90% of CaV 3.1 and CaV 3.3, but only 25% of CaV 3.2 currents. In order to investigate the toxin binding site, we generated a range of chimeric channels from the less sensitive CaV 3.2 and more sensitive CaV 3.3. Our results suggest that domain-1 of CaV 3.3 is important for the inhibitory effect of ω-Avsp1a on T-type calcium channels. Further studies revealed that a leucine of T-type calcium channels is crucial for the inhibitory effect of ω-Avsp1a. [ABSTRACT FROM AUTHOR]- Published
- 2022
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10. Cysteine-Rich α‑Conotoxin SII Displays Novel Interactions at the Muscle Nicotinic Acetylcholine Receptor.
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Wilhelm, Patrick, Luna-Ramirez, Karen, Chin, Yanni K.-Y., Dekan, Zoltan, Abraham, Nikita, Tae, Han-Shen, Chow, Chun Yuen, Eagles, David A., King, Glenn F., Lewis, Richard J., Adams, David J., and Alewood, Paul F.
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- 2022
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11. Synthesis and In vitro Biological Activity of Cyclic Lipophilic χ-Conotoxin MrIA Analogues
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Dekan, Zoltan, Paczkowski, Filip A., Lewis, Richard J., and Alewood, Paul F.
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- 2007
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12. Multitarget nociceptor sensitization by a promiscuous peptide from the venom of the King Baboon spider.
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Finol-Urdaneta, Rocio K., Ziegman, Rebekah, Dekan, Zoltan, McArthur, Jeffrey R., Heitmann, Stewart, Luna-Ramirez, Karen, Han-Shen Tae, Mueller, Alexander, Starobova, Hana, Chin, Yanni K.-Y., Wingerd, Joshua S., Undheim, Eivind A. B., Cristofori-Armstrong, Ben, Hill, Adam P., Herzig, Volker, King, Glenn F., Vetter, Irina, Rash, Lachlan D., Adams, David J., and Alewood, Paul F.
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PEPTIDES ,VENOM ,DORSAL root ganglia ,BABOONS ,SPIDER silk ,TARANTULAS - Abstract
The King Baboon spider, Pelinobius muticus, is a burrowing African tarantula. Its impressive size and appealing coloration are tempered by reports describing severe localized pain, swelling, itchiness, and muscle cramping after accidental envenomation. Hyperalgesia is the most prominent symptom after bites from P. muticus, but the molecular basis by which the venom induces pain is unknown. Proteotranscriptomic analysis of P. muticus venom uncovered a cysteine-rich peptide, δ/κ-theraphotoxin-Pm1a (δ/κ-TRTX-Pm1a), that elicited nocifensive behavior when injected into mice. In small dorsal root ganglion neurons, synthetic δ/κ-TRTX-Pm1a (sPm1a) induced hyperexcitability by enhancing tetrodotoxin-resistant sodium currents, impairing repolarization and lowering the threshold of action potential firing, consistent with the severe pain associated with envenomation. The molecular mechanism of nociceptor sensitization by sPm1a involves multimodal actions over several ion channel targets, including Na
V 1.8, KV 2.1, and tetrodotoxin-sensitive NaV channels. The promiscuous targeting of peptides like δ/κ-TRTX-Pm1a may be an evolutionary adaptation in pain-inducing defensive venoms. [ABSTRACT FROM AUTHOR]- Published
- 2022
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13. The Tarantula Venom Peptide Eo1a Binds to the Domain II S3-S4 Extracellular Loop of Voltage-Gated Sodium Channel NaV1.8 to Enhance Activation.
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Deuis, Jennifer R., Ragnarsson, Lotten, Robinson, Samuel D., Dekan, Zoltan, Chan, Lerena, Jin, Ai-Hua, Tran, Poanna, McMahon, Kirsten L., Li, Shengnan, Wood, John N., Cox, James J., King, Glenn F., Herzig, Volker, and Vetter, Irina
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SODIUM channels ,PEPTIDES ,VENOM ,TARANTULAS ,CONUS ,BINDING sites - Abstract
Venoms from cone snails and arachnids are a rich source of peptide modulators of voltage-gated sodium (Na
V ) channels, however relatively few venom-derived peptides with activity at the mammalian NaV 1.8 subtype have been isolated. Here, we describe the discovery and functional characterisation of β-theraphotoxin-Eo1a, a peptide from the venom of the Tanzanian black and olive baboon tarantula Encyocratella olivacea that modulates NaV 1.8. Eo1a is a 37-residue peptide that increases NaV 1.8 peak current (EC50 894 ± 146 nM) and causes a large hyperpolarising shift in both the voltage-dependence of activation (ΔV50 –20.5 ± 1.2 mV) and steady-state fast inactivation (ΔV50 –15.5 ± 1.8 mV). At a concentration of 10 μM, Eo1a has varying effects on the peak current and channel gating of NaV 1.1–NaV 1.7, although its activity is most pronounced at NaV 1.8. Investigations into the binding site of Eo1a using NaV 1.7/NaV 1.8 chimeras revealed a critical contribution of the DII S3-S4 extracellular loop of NaV 1.8 to toxin activity. Results from this work may form the basis for future studies that lead to the rational design of spider venom-derived peptides with improved potency and selectivity at NaV 1.8. [ABSTRACT FROM AUTHOR]- Published
- 2022
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14. Isolation, characterization and total regioselective synthesis of the novel μO-conotoxin MfVIA from Conus magnificus that targets voltage-gated sodium channels
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Vetter, Irina, Dekan, Zoltan, Knapp, Oliver, Adams, David J., Alewood, Paul F., and Lewis, Richard J.
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- 2012
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15. Nature-inspired dimerization as a strategy to modulate neuropeptide pharmacology exemplified with vasopressin and oxytocin.
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Dekan, Zoltan, Kremsmayr, Thomas, Keov, Peter, Godin, Mathilde, Teakle, Ngari, Dürrauer, Leopold, Xiang, Huang, Gharib, Dalia, Bergmayr, Christian, Hellinger, Roland, Gay, Marina, Vilaseca, Marta, Kurzbach, Dennis, Albericio, Fernando, Alewood, Paul F., Gruber, Christian W., and Muttenthaler, Markus
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- 2021
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16. Fulditoxin, representing a new class of dimeric snake toxins, defines novel pharmacology at nicotinic ACh receptors.
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Foo, Chun Shin, Jobichen, Chacko, Hassan‐Puttaswamy, Varuna, Dekan, Zoltan, Tae, Han‐Shen, Bertrand, Daniel, Adams, David J., Alewood, Paul F., Sivaraman, J., Nirthanan, Selvanayagam, Kini, R. Manjunatha, Hassan-Puttaswamy, Varuna, and Tae, Han-Shen
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SNAKE venom ,NICOTINIC receptors ,QUATERNARY structure ,PHARMACOLOGY ,ION channels ,SUGAMMADEX ,CONOTOXINS ,TOXINS ,RESEARCH ,CHOLINERGIC receptors ,ANIMAL experimentation ,RESEARCH methodology ,MEDICAL cooperation ,EVALUATION research ,ACETYLCHOLINE ,COMPARATIVE studies ,NICOTINIC antagonists ,RESEARCH funding ,AMINO acids ,PHARMACODYNAMICS - Abstract
Background and Purpose: Animal toxins have contributed significantly to our understanding of the neurobiology of receptors and ion channels. We studied the venom of the coral snake Micrurus fulvius fulvius and identified and characterized the structure and pharmacology of a new homodimeric neurotoxin, fulditoxin, that exhibited novel pharmacology at nicotinic ACh receptors (nAChRs).Experimental Approach: Fulditoxin was isolated by chromatography, chemically synthesized, its structure determined by X-ray crystallography, and its pharmacological actions on nAChRs characterized by organ bath assays and two-electrode voltage clamp electrophysiology.Key Results: Fulditoxin's distinct 1.95-Å quaternary structure revealed two short-chain three-finger α-neurotoxins (α-3FNTxs) non-covalently bound by hydrophobic interactions and an ability to bind metal and form tetrameric complexes, not reported previously for three-finger proteins. Although fulditoxin lacked all conserved amino acids canonically important for inhibiting nAChRs, it produced postsynaptic neuromuscular blockade of chick muscle at nanomolar concentrations, comparable to the prototypical α-bungarotoxin. This neuromuscular blockade was completely reversible, which is unusual for snake α-3FNTxs. Fulditoxin, therefore, interacts with nAChRs by utilizing a different pharmacophore. Unlike short-chain α-3FNTxs that bind only to muscle nAChRs, fulditoxin utilizes dimerization to expand its pharmacological targets to include human neuronal α4β2, α7, and α3β2 nAChRs which it blocked with IC50 values of 1.8, 7, and 12 μM respectively.Conclusions and Implications: Based on its distinct quaternary structure and unusual pharmacology, we named this new class of dimeric Micrurus neurotoxins represented by fulditoxin as Σ-neurotoxins, which offers greater insight into understanding the interactions between nAChRs and peptide antagonists. [ABSTRACT FROM AUTHOR]- Published
- 2020
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17. The α1-adrenoceptor inhibitor ρ-TIA facilitates net hunting in piscivorous Conus tulipa.
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Dutt, Mriga, Giacomotto, Jean, Ragnarsson, Lotten, Andersson, Åsa, Brust, Andreas, Dekan, Zoltan, Alewood, Paul F., and Lewis, Richard J.
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TULIPS ,CONUS ,ANIMAL behavior ,STARTLE reaction ,METHYL aspartate receptors ,ZEBRA danio embryos ,ZEBRA danio - Abstract
Cone snails use separately evolved venoms for prey capture and defence. While most use a harpoon for prey capture, the Gastridium clade that includes the well-studied Conus geographus and Conus tulipa, have developed a net hunting strategy to catch fish. This unique feeding behaviour requires secretion of "nirvana cabal" peptides to dampen the escape response of targeted fish allowing for their capture directly by mouth. However, the active components of the nirvana cabal remain poorly defined. In this study, we evaluated the behavioural effects of likely nirvana cabal peptides on the teleost model, Danio rerio (zebrafish). Surprisingly, the conantokins (NMDA receptor antagonists) and/or conopressins (vasopressin receptor agonists and antagonists) found in C. geographus and C. tulipa venom failed to produce a nirvana cabal-like effect in zebrafish. In contrast, low concentrations of the non-competitive adrenoceptor antagonist ρ-TIA found in C. tulipa venom (EC
50 = 190 nM) dramatically reduced the escape response of zebrafish larvae when added directly to aquarium water. ρ-TIA inhibited the zebrafish α1 -adrenoceptor, confirming ρ-TIA has the potential to reverse the known stimulating effects of norepinephrine on fish behaviour. ρ-TIA may act alone and not as part of a cabal, since it did not synergise with conopressins and/or conantokins. This study highlights the importance of using ecologically relevant animal behaviour models to decipher the complex neurobiology underlying the prey capture and defensive strategies of cone snails. [ABSTRACT FROM AUTHOR]- Published
- 2019
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18. Conotoxin Φ-MiXXVIIA from the Superfamily G2 Employs a Novel Cysteine Framework that Mimics Granulin and Displays Anti-Apoptotic Activity.
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Jin, Ai ‐ Hua, Dekan, Zoltan, Smout, Michael J., Wilson, David, Dutertre, Sébastien, Vetter, Irina, Lewis, Richard J., Loukas, Alex, Daly, Norelle L., and Alewood, Paul F.
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CYSTEINE , *DISULFIDES , *CONOTOXINS , *NEUROTOXIC agents , *NUCLEAR magnetic resonance spectroscopy - Abstract
Conotoxins are a large family of disulfide-rich peptides that contain unique cysteine frameworks that target a broad range of ion channels and receptors. We recently discovered the 33-residue conotoxin Φ-MiXXVIIA from Conus miles with a novel cysteine framework comprising three consecutive cysteine residues and four disulfide bonds. Regioselective chemical synthesis helped decipher the disulfide bond connectivity and the structure of Φ-MiXXVIIA was determined by NMR spectroscopy. The 3D structure displays a unique topology containing two β-hairpins that resemble the N-terminal domain of granulin. Similar to granulin, Φ-MiXXVIIA promotes cell proliferation (EC50 17.85 μ m) while inhibiting apoptosis (EC50 2.2 μ m). Additional framework XXVII sequences were discovered with homologous signal peptides that define the new conotoxin superfamily G2. The novel structure and biological activity of Φ-MiXXVIIA expands the repertoire of disulfide-rich conotoxins that recognize mammalian receptors. [ABSTRACT FROM AUTHOR]
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- 2017
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19. Modulatory features of the novel spider toxin μ-TRTX-Df1a isolated from the venom of the spider Davus fasciatus.
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Cardoso, Fernanda C, Dekan, Zoltan, Smith, Jennifer J, Deuis, Jennifer R, Vetter, Irina, Herzig, Volker, Alewood, Paul F, King, Glenn F, and Lewis, Richard J
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VOLTAGE-gated ion channels , *CHRONIC pain , *IMMUNOMODULATORS , *ELECTROPHYSIOLOGY , *LABORATORY rodents , *ANALGESICS , *ANIMAL experimentation , *ARTHROPOD venom , *BIOCHEMISTRY , *DOSE-effect relationship in pharmacology , *PHENOMENOLOGY , *MICE , *PAIN , *SPIDERS , *SODIUM channel blockers , *CANCER cell culture , *MEMBRANE transport proteins , *PHARMACODYNAMICS - Abstract
Background and Purpose: Naturally occurring dysfunction of voltage-gated sodium (NaV ) channels results in complex disorders such as chronic pain, making these channels an attractive target for new therapies. In the pursuit of novel NaV modulators, we investigated spider venoms for new inhibitors of NaV channels.Experimental Approach: We used high-throughput screens to identify a NaV modulator in venom of the spider Davus fasciatus. Further characterization of this venom peptide was undertaken using fluorescent and electrophysiological assays, molecular modelling and a rodent pain model.Key Results: We identified a potent NaV inhibitor named μ-TRTX-Df1a. This 34-residue peptide fully inhibited responses mediated by NaV 1.7 endogenously expressed in SH-SY5Y cells. Df1a also inhibited voltage-gated calcium (CaV 3) currents but had no activity against the voltage-gated potassium (KV 2) channel. The modelled structure of Df1a, which contains an inhibitor cystine knot motif, is reminiscent of the NaV channel toxin ProTx-I. Electrophysiology revealed that Df1a inhibits all NaV subtypes tested (hNaV 1.1-1.7). Df1a also slowed fast inactivation of NaV 1.1, NaV 1.3 and NaV 1.5 and modified the voltage-dependence of activation and inactivation of most of the NaV subtypes. Df1a preferentially binds to the domain II voltage-sensor and has additional interactions with the voltage sensors domains III and IV, which probably explains its modulatory features. Df1a was analgesic in vivo, reversing the spontaneous pain behaviours induced by the NaV activator OD1.Conclusion and Implications: μ-TRTX-Df1a shows potential as a new molecule for the development of drugs to treat pain disorders mediated by voltage-gated ion channels. [ABSTRACT FROM AUTHOR]- Published
- 2017
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20. Δ-Myrtoxin-Mp1a is a Helical Heterodimer from the Venom of the Jack Jumper Ant that has Antimicrobial, Membrane-Disrupting, and Nociceptive Activities.
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Dekan, Zoltan, Headey, Stephen J., Scanlon, Martin, Baldo, Brian A., Lee, Tzong‐Hsien, Aguilar, Marie‐Isabel, Deuis, Jennifer R., Vetter, Irina, Elliott, Alysha G., Amado, Maite, Cooper, Matthew A., Alewood, Dianne, and Alewood, Paul F.
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PEPTIDES , *TOXINS , *MYRMECIA , *ALLERGIES , *NAMES - Abstract
Δ-Myrtoxin-Mp1a (Mp1a), a 49-residue heterodimeric peptide from the venom of Myrmecia pilosula, comprises a 26-mer A chain and a 23-mer B chain connected by two disulfide bonds in an antiparallel arrangement. Combination of the individual synthetic chains through aerial oxidation remarkably resulted in the self-assembly of Mp1a as a homogenous product without the need for directed disulfide-bond formation. NMR analysis revealed a well-defined, unique structure containing an antiparallel α-helix pair. Dual polarization interferometry (DPI) analysis showed strong interaction with supported lipid bilayers and insertion within the bilayers. Mp1a caused non-specific Ca2+ influx in SH-SY5Y cells with a half maximal effective concentration (EC50) of 4.3 μ m. Mp1a also displayed broad-spectrum antimicrobial activity, with the highest potency against Gram-negative Acinetobacter baumannii (MIC 25 n m). Intraplantar injection (10 μ m) in mice elicited spontaneous pain and mechanical allodynia. Single- and two-chain mimetics of Mp1a revealed functional selectivity. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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21. Selective spider toxins reveal a role for the Nav1.1 channel in mechanical pain.
- Author
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Osteen, Jeremiah D., Herzig, Volker, Gilchrist, John, Emrick, Joshua J., Zhang, Chuchu, Wang, Xidao, Castro, Joel, Garcia-Caraballo, Sonia, Grundy, Luke, Rychkov, Grigori Y., Weyer, Andy D., Dekan, Zoltan, Undheim, Eivind A. B., Alewood, Paul, Stucky, Cheryl L., Brierley, Stuart M., Basbaum, Allan I., Bosmans, Frank, King, Glenn F., and Julius, David
- Published
- 2016
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22. Development of aμO-Conotoxin Analogue with Improved Lipid Membrane Interactions and Potency for the Analgesic Sodium Channel NaV1.8.
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Deuis, Jennifer R., Dekan, Zoltan, Inserra, Marco C., Lee, Tzong-Hsien, Aguilar, Marie-Isabel, Craik, David J., Lewis, Richard J., Alewood, Paul F., Mobli, Mehdi, Schroeder, Christina I., Henriques, Sónia Troeira, and Vetter, Irina
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CONOTOXINS , *BILAYER lipid membranes , *SODIUM channel inhibition , *PAIN management , *SURFACE charges , *LABORATORY mice - Abstract
The μO-conotoxins MrVIA, MrVIB, and MfVIA inhibit the voltage-gated sodium channel NaV1.8, a well described target for the treatment of pain; however, little is known about the residues or structural elements that define this activity. In this study, we determined the three-dimensional structure of MfVIA, examined its membrane binding properties, performed alaninescanning mutagenesis, and identified residues important for its activity at human NaV1.8.Asecond round of mutations resulted in (E5K,E8K)MfVIA, a double mutant with greater positive surface charge and greater affinity for lipid membranes compared with MfVIA. This analogue had increased potency atNaV1.8 and was analgesic in the mouse formalin assay. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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23. Analgesic Effects of GpTx-1, PF-04856264 and CNV1014802 in a Mouse Model of NaV1.7-Mediated Pain.
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Deuis, Jennifer R., Wingerd, Joshua S., Winter, Zoltan, Durek, Thomas, Dekan, Zoltan, Sousa, Silmara R., Zimmermann, Katharina, Hoffmann, Tali, Weidner, Christian, Nassar, Mohammed A., Alewood, Paul F., Lewis, Richard J., and Vetter, Irina
- Abstract
Loss-of-function mutations of Na
V 1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of NaV 1.7 a promising therapeutic strategy for the treatment of pain. We characterized a novel mouse model of NaV 1.7-mediated pain based on intraplantar injection of the scorpion toxin OD1, which is suitable for rapid in vivo profiling of NaV 1.7 inhibitors. Intraplantar injection of OD1 caused spontaneous pain behaviors, which were reversed by co-injection with NaV 1.7 inhibitors and significantly reduced in NaV 1.7–/– mice. To validate the use of the model for profiling NaV 1.7 inhibitors, we determined the NaV selectivity and tested the efficacy of the reported NaV 1.7 inhibitors GpTx-1, PF-04856264 and CNV1014802 (raxatrigine). GpTx-1 selectively inhibited NaV 1.7 and was effective when co-administered with OD1, but lacked efficacy when delivered systemically. PF-04856264 state-dependently and selectively inhibited NaV 1.7 and significantly reduced OD1-induced spontaneous pain when delivered locally and systemically. CNV1014802 state-dependently, but non-selectively, inhibited NaV channels and was only effective in the OD1 model when delivered systemically. Our novel model of NaV 1.7-mediated pain based on intraplantar injection of OD1 is thus suitable for the rapid in vivo characterization of the analgesic efficacy of NaV 1.7 inhibitors. [ABSTRACT FROM AUTHOR]- Published
- 2016
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24. Xenopus borealis as an alternative source of oocytes for biophysical and pharmacological studies of neuronal ion channels.
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Cristofori-Armstrong, Ben, Soh, Ming S., Talwar, Sahil, Brown, Darren L., Griffin, John D. O., Dekan, Zoltan, Stow, Jennifer L., King, Glenn F., Lynch, Joseph W., and Rash, Lachlan D.
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XENOPUS ,OVUM ,ION channels ,FLUORESCENCE ,FLUORIMETRY ,SCANNING electron microscopy - Abstract
For the past 30 years, oocytes from Xenopus laevis have been extensively used to express and characterise ion channels in an easily controlled environment. Here we report the first use of oocytes from the closely related species Xenopus borealis as an alternative expression system for neuronal ion channels. Using the two-electrode voltage-clamp technique, we show that a wide variety of voltageand ligand-gated ion channels have the same channel properties and pharmacological profiles when expressed in either X. laevis or X. borealis oocytes. Potential advantages of the X. borealis oocytes include a smaller endogenous chloride current and the ability to produce more intense fluorescence signals when studied with voltage-clamp fluorometry. Scanning electron microscopy revealed a difference in vitelline membrane structure between the two species, which may be related to the discrepancy in fluorescence signals observed. We demonstrate that X. borealis oocytes are a viable heterologous system for expression of neuronal ion channels with some potential advantages over X. laevis oocytes for certain applications. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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25. Total Synthesis of Human Hepcidin through Regioselective Disulfide-Bond Formation by using the Safety-Catch Cysteine Protecting Group 4,4′-Dimethylsulfinylbenzhydryl.
- Author
-
Dekan, Zoltan, Mobli, Mehdi, Pennington, Michael W., Fung, Eileen, Nemeth, Elizabeta, and Alewood, Paul F.
- Subjects
- *
HEPCIDIN , *CHEMICAL synthesis , *BOND formation mechanism , *REGIOSELECTIVITY (Chemistry) , *DISULFIDES , *CYSTEINE , *PEPTIDES , *NUCLEAR magnetic resonance - Abstract
A safety-catch cysteine protecting group, S-4,4′-dimethylsulfinylbenzhydryl (Msbh), was designed and developed to expand the capabilities of synthetic strategies for the regioselective formation of disulfide bonds in cysteine-rich peptides. The directed regioselective synthesis of human hepcidin, which contains four disulfide bonds, was undertaken and led to a high-resolution NMR structure under more physiologically relevant conditions than previously. Conversely, hepcidin synthesized with the formerly assigned vicinal disulfide-bond connectivity displayed significant conformational heterogeneity under similar conditions. The two synthetic forms of human hepcidin induced ferroportin internalization with apparent EC50 values of 2.0 (native fold, 1) and 4.4 n M (non-native fold, 2), with 2 undergoing isomerization to 1 in the presence of ferroportin expressing cells. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
26. α-Conotoxin ImI Incorporating Stable Cystathionine Bridges Maintains Full Potency and Identical Three-Dimensional Structure.
- Author
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Dekan, Zoltan, Vetter, Irina, Daly, Norelle L., Craik, David J., Lewis, Richard J., and Alewood, Paul F.
- Subjects
- *
PEPTIDES , *GLUTATHIONE , *ENZYMES , *LACTAMS , *CHOLINERGIC receptors , *SULFIDES - Abstract
The two disulfide bonds of α-conotoxin ImI, a peptide antagonist of the α7 nicotinic acetylcholine receptor (nAChR), were systematically replaced with isosteric redox-stable cystathionine thioethers. Regioselective thioether formation was accomplished on solid support through substitution of a γ-chlorohomoalanine by an intramolecular cysteine thiol to produce hybrid thioether/disulfide analogues (2 and 3) as well as a dual cystathionine analogue (4) that were found to be structurally homologous to α-conotoxin ImI by 1H NMR. The antagonistic activity at the α7 nAChR of cystathionine analogue 3 (pIC50 = 6.41 ± 0.09) was identical to that of α-conotoxin ImI (1, pIC50 = 6.41 ± 0.09), whereas those of 2 (pIC50 = 5.96 ± 0.09) and 4 (pIC50 = 5.89 ± 0.09) showed a modest decrease. The effect of oxidation of the thioethers to sulfoxides was also investigated, with significant changes in the biological activities observed ranging from a >30-fold reduction (2S═O) to a 3-fold increase (3S═OB) in potencies. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
27. Modulating Oxytocin Activity and Plasma Stability by Disulfide Bond Engineering.
- Author
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Muttenthaler, Markus, Andersson, Asa, de Araujo, Aline D., Dekan, Zoltan, Lewis, Richard J., and Alewood, Paul F.
- Published
- 2010
- Full Text
- View/download PDF
28. It Takes Two: Dimerization Is Essential for the Broad-Spectrum Predatory and Defensive Activities of the Venom Peptide Mp1a from the Jack Jumper Ant Myrmecia pilosula.
- Author
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Nixon, Samantha A., Dekan, Zoltan, Robinson, Samuel D., Guo, Shaodong, Vetter, Irina, Kotze, Andrew C., Alewood, Paul F., King, Glenn F., and Herzig, Volker
- Subjects
VENOM ,ANTS ,DIMERIZATION ,HAEMONCHUS contortus ,SENSORY neurons - Abstract
Ant venoms have recently attracted increased attention due to their chemical complexity, novel molecular frameworks, and diverse biological activities. The heterodimeric peptide ∆-myrtoxin-Mp1a (Mp1a) from the venom of the Australian jack jumper ant, Myrmecia pilosula, exhibits antimicrobial, membrane-disrupting, and pain-inducing activities. In the present study, we examined the activity of Mp1a and a panel of synthetic analogues against the gastrointestinal parasitic nematode Haemonchus contortus, the fruit fly Drosophila melanogaster, and for their ability to stimulate pain-sensing neurons. Mp1a was found to be both insecticidal and anthelmintic, and it robustly activated mammalian sensory neurons at concentrations similar to those reported to elicit antimicrobial and cytotoxic activity. The native antiparallel Mp1a heterodimer was more potent than heterodimers with alternative disulfide connectivity, as well as monomeric analogues. We conclude that the membrane-disrupting effects of Mp1a confer broad-spectrum biological activities that facilitate both predation and defense for the ant. Our structure–activity data also provide a foundation for the rational engineering of analogues with selectivity for particular cell types. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
29. Addition of K22 Converts Spider Venom Peptide Pme2a from an Activator to an Inhibitor of NaV1.7.
- Author
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Yin, Kathleen, Deuis, Jennifer R., Dekan, Zoltan, Jin, Ai-Hua, Alewood, Paul F., King, Glenn F., Herzig, Volker, and Vetter, Irina
- Subjects
SPIDER venom ,SODIUM channels ,MEMBRANE potential ,PEPTIDES ,TARANTULAS ,VENOM - Abstract
Spider venom is a novel source of disulfide-rich peptides with potent and selective activity at voltage-gated sodium channels (Na
V ). Here, we describe the discovery of μ-theraphotoxin-Pme1a and μ/δ-theraphotoxin-Pme2a, two novel peptides from the venom of the Gooty Ornamental tarantula Poecilotheria metallica that modulate NaV channels. Pme1a is a 35 residue peptide that inhibits NaV 1.7 peak current (IC50 334 ± 114 nM) and shifts the voltage dependence of activation to more depolarised membrane potentials (V1/2 activation: Δ = +11.6 mV). Pme2a is a 33 residue peptide that delays fast inactivation and inhibits NaV 1.7 peak current (EC50 > 10 μM). Synthesis of a [+22K]Pme2a analogue increased potency at NaV 1.7 (IC50 5.6 ± 1.1 μM) and removed the effect of the native peptide on fast inactivation, indicating that a lysine at position 22 (Pme2a numbering) is important for inhibitory activity. Results from this study may be used to guide the rational design of spider venom-derived peptides with improved potency and selectivity at NaV channels in the future. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
30. Corrigendum: Pharmacological characterisation of the highly NaV1.7 selective spider venom peptide Pn3a.
- Author
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Deuis, Jennifer R., Dekan, Zoltan, Wingerd, Joshua S., Smith, Jennifer J., Munasinghe, Nehan R., Bhola, Rebecca F., Imlach, Wendy L., Herzig, Volker, Armstrong, David A., Rosengren, K. Johan, Bosmans, Frank, Waxman, Stephen G., Dib-Hajj, Sulayman D., Escoubas, Pierre, Minett, Michael S., Christie, Macdonald J., King, Glenn F., Alewood, Paul F., Lewis, Richard J., and Wood, John N.
- Published
- 2017
- Full Text
- View/download PDF
31. Novel venom-derived inhibitors of the human EAG channel, a putative antiepileptic drug target.
- Author
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Ma, Linlin, Chin, Yanni K.Y., Dekan, Zoltan, Herzig, Volker, Chow, Chun Yuen, Heighway, Jacqueline, Lam, Sau Wing, Guillemin, Gilles J., Alewood, Paul F., and King, Glenn F.
- Subjects
- *
ANTICONVULSANTS , *DRUG target , *GENETIC mutation , *POTASSIUM channels , *DEVELOPMENTAL disabilities , *EPILEPSY - Abstract
Graphical abstract Abstract Recently, we and other groups revealed that gain-of-function mutations in the human ether à go-go voltage-gated potassium channel hEAG1 (K v 10.1) lead to developmental disorders with associated infantile-onset epilepsy. However, the physiological role of hEAG1 in the central nervous system remains elusive. Potent and selective antagonists of hEAG1 are therefore much sought after, both as pharmacological tools for studying the (patho)physiological functions of this enigmatic channel and as potential leads for development of anti-epileptic drugs. Since animal venoms are a rich source of potent ion channel modifiers that have been finely tuned by millions of year of evolution, we screened 108 arachnid venoms for hEAG1 inhibitors using electrophysiology. Two hit peptides (Aa1a and Ap1a) were isolated, sequenced, and chemically synthesised for structure-function studies. Both of these hEAG1 inhibitors are C-terminally amidated peptides containing an inhibitor cystine knot motif, which provides them with exceptional stability in both plasma and cerebrospinal fluid. Aa1a and Ap1a are the most potent peptidic inhibitors of hEAG1 reported to date, and they present a novel mode of action by targeting both the activation and inactivation gating of the channel. These peptides should be useful pharmacological tools for probing hEAG1 function as well as informative leads for the development of novel anti-epileptic drugs. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
32. Selenoether oxytocin analogues have analgesic properties in a mouse model of chronic abdominal pain.
- Author
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de Araujo, Aline Dantas, Mobli, Mehdi, Castro, Joel, Harrington, Andrea M., Vetter, Irina, Dekan, Zoltan, Muttenthaler, Markus, Wan, JingJing, Lewis, Richard J., King, Glenn F., Brierley, Stuart M., and Alewood, Paul F.
- Published
- 2014
- Full Text
- View/download PDF
33. A Tarantula-Venom Peptide Antagonizes the TRPA1 Nociceptor Ion Channel by Binding to the S1–S4 Gating Domain.
- Author
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Gui, Junhong, Liu, Boyi, Cao, Guan, Lipchik, Andrew?M., Perez, Minervo, Dekan, Zoltan, Mobli, Mehdi, Daly, Norelle?L., Alewood, Paul?F., Parker, Laurie?L., King, Glenn?F., Zhou, Yufeng, Jordt, Sven-Eric, and Nitabach, Michael?N.
- Subjects
- *
TARANTULAS , *PEPTIDES , *ANTIBIOSIS , *ANTISENSE DNA , *ION channels , *NOCICEPTORS ,PHYSIOLOGICAL effects of venom - Abstract
Summary: Background: The venoms of predators have been an excellent source of diverse highly specific peptides targeting ion channels. Here we describe the first known peptide antagonist of the nociceptor ion channel transient receptor potential ankyrin 1 (TRPA1). Results: We constructed a recombinant cDNA library encoding ∼100 diverse GPI-anchored peptide toxins (t-toxins) derived from spider venoms and screened this library by coexpression in Xenopus oocytes with TRPA1. This screen resulted in identification of protoxin-I (ProTx-I), a 35-residue peptide from the venom of the Peruvian green-velvet tarantula, Thrixopelma pruriens, as the first known high-affinity peptide TRPA1 antagonist. ProTx-I was previously identified as an antagonist of voltage-gated sodium (NaV) channels. We constructed a t-toxin library of ProTx-I alanine-scanning mutants and screened this library against NaV1.2 and TRPA1. This revealed distinct partially overlapping surfaces of ProTx-I by which it binds to these two ion channels. Importantly, this mutagenesis yielded two novel ProTx-I variants that are only active against either TRPA1or NaV1.2. By testing its activity against chimeric channels, we identified the extracellular loops of the TRPA1 S1–S4 gating domain as the ProTx-I binding site. Conclusions: These studies establish our approach, which we term “toxineering,” as a generally applicable method for isolation of novel ion channel modifiers and design of ion channel modifiers with altered specificity. They also suggest that ProTx-I will be a valuable pharmacological reagent for addressing biophysical mechanisms of TRPA1 gating and the physiology of TRPA1 function in nociceptors, as well as for potential clinical application in the context of pain and inflammation. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
34. Mutational analysis of ProTx-I and the novel venom peptide Pe1b provide insight into residues responsible for selective inhibition of the analgesic drug target NaV1.7.
- Author
-
Rupasinghe, Darshani B., Herzig, Volker, Vetter, Irina, Dekan, Zoltan, Gilchrist, John, Bosmans, Frank, Alewood, Paul F., Lewis, Richard J., and King, Glenn F.
- Subjects
- *
VENOM , *SPIDER venom , *CONOTOXINS , *DRUG target , *ANALGESICS , *TREATMENT effectiveness , *PAIN management - Abstract
Management of chronic pain presents a major challenge, since many currently available treatments lack efficacy and have problems such as addiction and tolerance. Loss of function mutations in the SCN9A gene lead to a congenital inability to feel pain, with no other sensory deficits aside from anosmia. SCN9A encodes the voltage-gated sodium (Na V) channel 1.7 (Na V 1.7), which has been identified as a primary pain target. However, in developing Na V 1.7-targeted analgesics, extreme care must to be taken to avoid off-target activity on other Na V subtypes that are critical for survival. Since spider venoms are an excellent source of Na V channel modulators, we screened a panel of spider venoms to identify selective Na V 1.7 inhibitors. This led to identification of two novel Na V modulating venom peptides (β/μ-theraphotoxin-Pe1a and β/μ-theraphotoxin-Pe1b (Pe1b) from the arboreal tarantula Phormingochilus everetti. A third peptide isolated from the tarantula Bumba pulcherrimaklaasi was identical to the well-known ProTx-I (β/ω-theraphotoxin-Tp1a) from the tarantula Thrixopelma pruriens. A tethered toxin (t-toxin)-based alanine scanning strategy was used to determine the Na V 1.7 pharmacophore of ProTx-I. We designed several ProTx-I and Pe1b analogues, and tested them for activity and Na V channel subtype selectivity. Several analogues had improved potency against Na V 1.7, and altered specificity against other Na V channels. These analogues provide a foundation for development of Pe1b as a lead molecule for therapeutic inhibition of Na V 1.7. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
35. The Tarantula Venom Peptide Eo1a Binds to the Domain II S3-S4 Extracellular Loop of Voltage-Gated Sodium Channel Na V 1.8 to Enhance Activation.
- Author
-
Deuis JR, Ragnarsson L, Robinson SD, Dekan Z, Chan L, Jin AH, Tran P, McMahon KL, Li S, Wood JN, Cox JJ, King GF, Herzig V, and Vetter I
- Abstract
Venoms from cone snails and arachnids are a rich source of peptide modulators of voltage-gated sodium (Na
V ) channels, however relatively few venom-derived peptides with activity at the mammalian NaV 1.8 subtype have been isolated. Here, we describe the discovery and functional characterisation of β-theraphotoxin-Eo1a, a peptide from the venom of the Tanzanian black and olive baboon tarantula Encyocratella olivacea that modulates NaV 1.8. Eo1a is a 37-residue peptide that increases NaV 1.8 peak current (EC50 894 ± 146 nM) and causes a large hyperpolarising shift in both the voltage-dependence of activation (ΔV50 -20.5 ± 1.2 mV) and steady-state fast inactivation (ΔV50 -15.5 ± 1.8 mV). At a concentration of 10 μM, Eo1a has varying effects on the peak current and channel gating of NaV 1.1-NaV 1.7, although its activity is most pronounced at NaV 1.8. Investigations into the binding site of Eo1a using NaV 1.7/NaV 1.8 chimeras revealed a critical contribution of the DII S3-S4 extracellular loop of NaV 1.8 to toxin activity. Results from this work may form the basis for future studies that lead to the rational design of spider venom-derived peptides with improved potency and selectivity at NaV 1.8., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Deuis, Ragnarsson, Robinson, Dekan, Chan, Jin, Tran, McMahon, Li, Wood, Cox, King, Herzig and Vetter.)- Published
- 2022
- Full Text
- View/download PDF
36. Mapping the Molecular Surface of the Analgesic Na V 1.7-Selective Peptide Pn3a Reveals Residues Essential for Membrane and Channel Interactions.
- Author
-
Mueller A, Dekan Z, Kaas Q, Agwa AJ, Starobova H, Alewood PF, Schroeder CI, Mobli M, Deuis JR, and Vetter I
- Abstract
Compelling human genetic studies have identified the voltage-gated sodium channel Na
V 1.7 as a promising therapeutic target for the treatment of pain. The analgesic spider-venom-derived peptide μ-theraphotoxin-Pn3a is an exceptionally potent and selective inhibitor of NaV 1.7; however, little is known about the structure-activity relationships or channel interactions that define this activity. We rationally designed 17 Pn3a analogues and determined their activity at hNaV 1.7 using patch-clamp electrophysiology. The positively charged amino acids K22 and K24 were identified as crucial for Pn3a activity, with molecular modeling identifying interactions of these residues with the S3-S4 loop of domain II of hNaV 1.7. Removal of hydrophobic residues Y4, Y27, and W30 led to a loss of potency (>250-fold), while replacement of negatively charged D1 and D8 residues with a positively charged lysine led to increased potencies (>13-fold), likely through alterations in membrane lipid interactions. Mutating D8 to an asparagine led to the greatest improvement in Pn3a potency at NaV 1.7 (20-fold), while maintaining >100-fold selectivity over the major off-targets NaV 1.4, NaV 1.5, and NaV 1.6. The Pn3a[D8N] mutant retained analgesic activity in vivo , significantly attenuating mechanical allodynia in a clinically relevant mouse model of postsurgical pain at doses 3-fold lower than those with wild-type Pn3a, without causing motor-adverse effects. Results from this study will facilitate future rational design of potent and selective peptidic NaV 1.7 inhibitors for the development of more efficacious and safer analgesics as well as to further investigate the involvement of NaV 1.7 in pain., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)- Published
- 2020
- Full Text
- View/download PDF
37. Corrigendum: Pharmacological characterisation of the highly Na V 1.7 selective spider venom peptide Pn3a.
- Author
-
Deuis JR, Dekan Z, Wingerd JS, Smith JJ, Munasinghe NR, Bhola RF, Imlach WL, Herzig V, Armstrong DA, Rosengren KJ, Bosmans F, Waxman SG, Dib-Hajj SD, Escoubas P, Minett MS, Christie MJ, King GF, Alewood PF, Lewis RJ, Wood JN, and Vetter I
- Published
- 2017
- Full Text
- View/download PDF
38. Pharmacological characterisation of the highly Na V 1.7 selective spider venom peptide Pn3a.
- Author
-
Deuis JR, Dekan Z, Wingerd JS, Smith JJ, Munasinghe NR, Bhola RF, Imlach WL, Herzig V, Armstrong DA, Rosengren KJ, Bosmans F, Waxman SG, Dib-Hajj SD, Escoubas P, Minett MS, Christie MJ, King GF, Alewood PF, Lewis RJ, Wood JN, and Vetter I
- Abstract
Human genetic studies have implicated the voltage-gated sodium channel Na
V 1.7 as a therapeutic target for the treatment of pain. A novel peptide, μ-theraphotoxin-Pn3a, isolated from venom of the tarantula Pamphobeteus nigricolor, potently inhibits NaV 1.7 (IC50 0.9 nM) with at least 40-1000-fold selectivity over all other NaV subtypes. Despite on-target activity in small-diameter dorsal root ganglia, spinal slices, and in a mouse model of pain induced by NaV 1.7 activation, Pn3a alone displayed no analgesic activity in formalin-, carrageenan- or FCA-induced pain in rodents when administered systemically. A broad lack of analgesic activity was also found for the selective NaV 1.7 inhibitors PF-04856264 and phlotoxin 1. However, when administered with subtherapeutic doses of opioids or the enkephalinase inhibitor thiorphan, these subtype-selective NaV 1.7 inhibitors produced profound analgesia. Our results suggest that in these inflammatory models, acute administration of peripherally restricted NaV 1.7 inhibitors can only produce analgesia when administered in combination with an opioid.- Published
- 2017
- Full Text
- View/download PDF
39. Development of a μO-Conotoxin Analogue with Improved Lipid Membrane Interactions and Potency for the Analgesic Sodium Channel NaV1.8.
- Author
-
Deuis JR, Dekan Z, Inserra MC, Lee TH, Aguilar MI, Craik DJ, Lewis RJ, Alewood PF, Mobli M, Schroeder CI, Henriques ST, and Vetter I
- Subjects
- Amino Acid Sequence, Animals, Behavior, Animal drug effects, Crystallography, X-Ray, Electrophysiology, HEK293 Cells, Humans, Liposomes, Magnetic Resonance Spectroscopy, Male, Mice, Mice, Inbred C57BL, Molecular Sequence Data, NAV1.8 Voltage-Gated Sodium Channel chemistry, NAV1.8 Voltage-Gated Sodium Channel genetics, Pain chemically induced, Protein Conformation, Sequence Homology, Amino Acid, Analgesics pharmacology, Cell Membrane metabolism, Conotoxins pharmacology, NAV1.8 Voltage-Gated Sodium Channel metabolism, Pain prevention & control
- Abstract
The μO-conotoxins MrVIA, MrVIB, and MfVIA inhibit the voltage-gated sodium channel NaV1.8, a well described target for the treatment of pain; however, little is known about the residues or structural elements that define this activity. In this study, we determined the three-dimensional structure of MfVIA, examined its membrane binding properties, performed alanine-scanning mutagenesis, and identified residues important for its activity at human NaV1.8. A second round of mutations resulted in (E5K,E8K)MfVIA, a double mutant with greater positive surface charge and greater affinity for lipid membranes compared with MfVIA. This analogue had increased potency at NaV1.8 and was analgesic in the mouse formalin assay., (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Published
- 2016
- Full Text
- View/download PDF
40. Analgesic Effects of GpTx-1, PF-04856264 and CNV1014802 in a Mouse Model of NaV1.7-Mediated Pain.
- Author
-
Deuis JR, Wingerd JS, Winter Z, Durek T, Dekan Z, Sousa SR, Zimmermann K, Hoffmann T, Weidner C, Nassar MA, Alewood PF, Lewis RJ, and Vetter I
- Subjects
- Analgesics, Animals, Behavior, Animal drug effects, CHO Cells, Cricetulus, Disease Models, Animal, HEK293 Cells, Humans, Male, Mice, Inbred C57BL, NAV1.7 Voltage-Gated Sodium Channel genetics, Nerve Fibers drug effects, Nerve Fibers physiology, Pain chemically induced, Proline therapeutic use, Saphenous Vein innervation, Sulfonamides therapeutic use, NAV1.7 Voltage-Gated Sodium Channel physiology, Pain drug therapy, Peptides therapeutic use, Phenyl Ethers therapeutic use, Proline analogs & derivatives, Scorpion Venoms therapeutic use, Sodium Channel Blockers therapeutic use, Spider Venoms therapeutic use
- Abstract
Loss-of-function mutations of Na(V)1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of Na(V)1.7 a promising therapeutic strategy for the treatment of pain. We characterized a novel mouse model of Na(V)1.7-mediated pain based on intraplantar injection of the scorpion toxin OD1, which is suitable for rapid in vivo profiling of Na(V)1.7 inhibitors. Intraplantar injection of OD1 caused spontaneous pain behaviors, which were reversed by co-injection with Na(V)1.7 inhibitors and significantly reduced in Na(V)1.7(-/-) mice. To validate the use of the model for profiling Na(V)1.7 inhibitors, we determined the Na(V) selectivity and tested the efficacy of the reported Na(V)1.7 inhibitors GpTx-1, PF-04856264 and CNV1014802 (raxatrigine). GpTx-1 selectively inhibited Na(V)1.7 and was effective when co-administered with OD1, but lacked efficacy when delivered systemically. PF-04856264 state-dependently and selectively inhibited Na(V)1.7 and significantly reduced OD1-induced spontaneous pain when delivered locally and systemically. CNV1014802 state-dependently, but non-selectively, inhibited Na(V) channels and was only effective in the OD1 model when delivered systemically. Our novel model of Na(V)1.7-mediated pain based on intraplantar injection of OD1 is thus suitable for the rapid in vivo characterization of the analgesic efficacy of Na(V)1.7 inhibitors.
- Published
- 2016
- Full Text
- View/download PDF
41. Identification and Characterization of ProTx-III [μ-TRTX-Tp1a], a New Voltage-Gated Sodium Channel Inhibitor from Venom of the Tarantula Thrixopelma pruriens.
- Author
-
Cardoso FC, Dekan Z, Rosengren KJ, Erickson A, Vetter I, Deuis JR, Herzig V, Alewood PF, King GF, and Lewis RJ
- Subjects
- Analgesics chemistry, Analgesics isolation & purification, Animals, CHO Cells, Cell Line, Tumor, Cricetulus, Disease Models, Animal, HEK293 Cells, Humans, Male, Mass Spectrometry, Mice, Mice, Inbred C57BL, Models, Molecular, NAV1.7 Voltage-Gated Sodium Channel metabolism, Pain chemically induced, Scorpion Venoms, Spider Venoms chemistry, Spider Venoms isolation & purification, Spiders classification, Voltage-Gated Sodium Channel Blockers chemistry, Voltage-Gated Sodium Channel Blockers isolation & purification, Analgesics pharmacology, Pain drug therapy, Spider Venoms pharmacology, Spiders metabolism, Voltage-Gated Sodium Channel Blockers pharmacology
- Abstract
Spider venoms are a rich source of ion channel modulators with therapeutic potential. Given the analgesic potential of subtype-selective inhibitors of voltage-gated sodium (NaV) channels, we screened spider venoms for inhibitors of human NaV1.7 (hNaV1.7) using a high-throughput fluorescent assay. Here, we describe the discovery of a novel NaV1.7 inhibitor, μ-TRTX-Tp1a (Tp1a), isolated from the venom of the Peruvian green-velvet tarantula Thrixopelma pruriens. Recombinant and synthetic forms of this 33-residue peptide preferentially inhibited hNaV1.7 > hNaV1.6 > hNaV1.2 > hNaV1.1 > hNaV1.3 channels in fluorescent assays. NaV1.7 inhibition was diminished (IC50 11.5 nM) and the association rate decreased for the C-terminal acid form of Tp1a compared with the native amidated form (IC50 2.1 nM), suggesting that the peptide C terminus contributes to its interaction with hNaV1.7. Tp1a had no effect on human voltage-gated calcium channels or nicotinic acetylcholine receptors at 5 μM. Unlike most spider toxins that modulate NaV channels, Tp1a inhibited hNaV1.7 without significantly altering the voltage dependence of activation or inactivation. Tp1a proved to be analgesic by reversing spontaneous pain induced in mice by intraplantar injection in OD1, a scorpion toxin that potentiates hNaV1.7. The structure of Tp1a as determined using NMR spectroscopy revealed a classic inhibitor cystine knot (ICK) motif. The molecular surface of Tp1a presents a hydrophobic patch surrounded by positively charged residues, with subtle differences from other ICK spider toxins that might contribute to its different pharmacological profile. Tp1a may help guide the development of more selective and potent hNaV1.7 inhibitors for treatment of chronic pain., (Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.)
- Published
- 2015
- Full Text
- View/download PDF
42. Conotoxin engineering: dual pharmacophoric noradrenaline transport inhibitor/integrin binding peptide with improved stability.
- Author
-
Dekan Z, Wang CI, Andrews RK, Lewis RJ, and Alewood PF
- Subjects
- Animals, Conotoxins chemistry, Conotoxins pharmacokinetics, Humans, Integrins antagonists & inhibitors, Models, Molecular, Norepinephrine Plasma Membrane Transport Proteins antagonists & inhibitors, Oligopeptides, Peptides, Cyclic metabolism, Protein Stability, Rats, Biological Transport drug effects, Conotoxins metabolism, Conotoxins pharmacology, Integrins metabolism, Norepinephrine metabolism, Protein Engineering methods
- Abstract
A dual-pharmacophoric peptide was engineered by grafting the integrin binding RGD motif between the C- and N-termini of a disulfide-rich noradrenaline transporter inhibiting χ-conotoxin resulting in a stable backbone cyclized peptide. The construct maintained two independent biological activities and showed increased plasma stability with no adverse effects observed following administration to rats, highlighting the potential value of pharmacophore grafting into constrained peptide scaffolds.
- Published
- 2012
- Full Text
- View/download PDF
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