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Cone snail venoms are richly decorated with posttranslational modifications. We show that tyrosine sulfation and C-terminal amidation increase the structural stability and binding of α-conotoxins.
Thao N. T. Ho; Han Siean Lee; Shilpa Swaminathan; Lewis Goodwin; Nishant Rai; Brianna Ushay; Richard J. Lewis; K. Johan Rosengren; Anne C. Conibear. Posttranslational modifications of α-conotoxins: sulfotyrosine and C-terminal amidation stabilise structures and increase acetylcholine receptor binding. RSC Medicinal Chemistry 2021, 1 .
AMA StyleThao N. T. Ho, Han Siean Lee, Shilpa Swaminathan, Lewis Goodwin, Nishant Rai, Brianna Ushay, Richard J. Lewis, K. Johan Rosengren, Anne C. Conibear. Posttranslational modifications of α-conotoxins: sulfotyrosine and C-terminal amidation stabilise structures and increase acetylcholine receptor binding. RSC Medicinal Chemistry. 2021; ():1.
Chicago/Turabian StyleThao N. T. Ho; Han Siean Lee; Shilpa Swaminathan; Lewis Goodwin; Nishant Rai; Brianna Ushay; Richard J. Lewis; K. Johan Rosengren; Anne C. Conibear. 2021. "Posttranslational modifications of α-conotoxins: sulfotyrosine and C-terminal amidation stabilise structures and increase acetylcholine receptor binding." RSC Medicinal Chemistry , no. : 1.
We review and develop conceptual models for the bio-transfer of ciguatoxins in food chains for Platypus Bay and the Great Barrier Reef on the east coast of Australia. Platypus Bay is unique in repeatedly producing ciguateric fishes in Australia, with ciguatoxins produced by benthic dinoflagellates (Gambierdiscus spp.) growing epiphytically on free-living, benthic macroalgae. The Gambierdiscus are consumed by invertebrates living within the macroalgae, which are preyed upon by small carnivorous fishes, which are then preyed upon by Spanish mackerel (Scomberomorus commerson). We hypothesise that Gambierdiscus and/or Fukuyoa species growing on turf algae are the main source of ciguatoxins entering marine food chains to cause ciguatera on the Great Barrier Reef. The abundance of surgeonfish that feed on turf algae may act as a feedback mechanism controlling the flow of ciguatoxins through this marine food chain. If this hypothesis is broadly applicable, then a reduction in herbivory from overharvesting of herbivores could lead to increases in ciguatera by concentrating ciguatoxins through the remaining, smaller population of herbivores. Modelling the dilution of ciguatoxins by somatic growth in Spanish mackerel and coral trout (Plectropomus leopardus) revealed that growth could not significantly reduce the toxicity of fish flesh, except in young fast-growing fishes or legal-sized fishes contaminated with low levels of ciguatoxins. If Spanish mackerel along the east coast of Australia can depurate ciguatoxins, it is most likely with a half-life of ≤1-year. Our review and conceptual models can aid management and research of ciguatera in Australia, and globally.
Michael Holmes; Bill Venables; Richard Lewis. Critical Review and Conceptual and Quantitative Models for the Transfer and Depuration of Ciguatoxins in Fishes. Toxins 2021, 13, 515 .
AMA StyleMichael Holmes, Bill Venables, Richard Lewis. Critical Review and Conceptual and Quantitative Models for the Transfer and Depuration of Ciguatoxins in Fishes. Toxins. 2021; 13 (8):515.
Chicago/Turabian StyleMichael Holmes; Bill Venables; Richard Lewis. 2021. "Critical Review and Conceptual and Quantitative Models for the Transfer and Depuration of Ciguatoxins in Fishes." Toxins 13, no. 8: 515.
Ciguatera fish poisoning (CFP) and neurotoxic shellfish poisoning syndromes are induced by the consumption of seafood contaminated by ciguatoxins and brevetoxins. Both toxins cause sensory symptoms such as paresthesia, cold dysesthesia and painful disorders. An intense pruritus, which may become chronic, occurs also in CFP. No curative treatment is available and the pathophysiology is not fully elucidated. Here we conducted single-cell calcium video-imaging experiments in sensory neurons from newborn rats to study in vitro the ability of Pacific-ciguatoxin-2 (P-CTX-2) and brevetoxin-1 (PbTx-1) to sensitize receptors and ion channels, (i.e., to increase the percentage of responding cells and/or the response amplitude to their pharmacological agonists). In addition, we studied the neurotrophin release in sensory neurons co-cultured with keratinocytes after exposure to P-CTX-2. Our results show that P-CTX-2 induced the sensitization of TRPA1, TRPV4, PAR2, MrgprC, MrgprA and TTX-r NaV channels in sensory neurons. P-CTX-2 increased the release of nerve growth factor and brain-derived neurotrophic factor in the co-culture supernatant, suggesting that those neurotrophins could contribute to the sensitization of the aforementioned receptors and channels. Our results suggest the potential role of sensitization of sensory receptors/ion channels in the induction or persistence of sensory disturbances in CFP syndrome.
Ophélie Pierre; Maxime Fouchard; Nelig Le Goux; Paul Buscaglia; Raphaël Leschiera; Richard Lewis; Olivier Mignen; Joachim Fluhr; Laurent Misery; Raphaële Le Garrec. Pacific-Ciguatoxin-2 and Brevetoxin-1 Induce the Sensitization of Sensory Receptors Mediating Pain and Pruritus in Sensory Neurons. Marine Drugs 2021, 19, 387 .
AMA StyleOphélie Pierre, Maxime Fouchard, Nelig Le Goux, Paul Buscaglia, Raphaël Leschiera, Richard Lewis, Olivier Mignen, Joachim Fluhr, Laurent Misery, Raphaële Le Garrec. Pacific-Ciguatoxin-2 and Brevetoxin-1 Induce the Sensitization of Sensory Receptors Mediating Pain and Pruritus in Sensory Neurons. Marine Drugs. 2021; 19 (7):387.
Chicago/Turabian StyleOphélie Pierre; Maxime Fouchard; Nelig Le Goux; Paul Buscaglia; Raphaël Leschiera; Richard Lewis; Olivier Mignen; Joachim Fluhr; Laurent Misery; Raphaële Le Garrec. 2021. "Pacific-Ciguatoxin-2 and Brevetoxin-1 Induce the Sensitization of Sensory Receptors Mediating Pain and Pruritus in Sensory Neurons." Marine Drugs 19, no. 7: 387.
The venom duct origins of predatory and defensive venoms has not been studied for hook-and-line fish hunting cone snails despite the pharmacological importance of their venoms. To better understand the biochemistry and evolution of injected predatory and defensive venoms, we compared distal, central and proximal venom duct sections across three specimens of C. striatus (Pionoconus) using proteomic and transcriptomic approaches. A total of 370 conotoxin precursors were identified from the whole venom duct transcriptome. Milked defensive venom was enriched with a potent cocktail of proximally expressed inhibitory α-, ω- and μ-conotoxins compared to milked predatory venom. In contrast, excitatory κA-conotoxins dominated both the predatory and defensive venoms despite their distal expression, suggesting this class of conotoxin can be selectively expressed from the same duct segment in response to either a predatory or defensive stimuli. Given the high abundance of κA-conotoxins in the Pionoconus clade, we hypothesise that the κA-conotoxins have evolved through adaptive evolution following their repurposing from ancestral inhibitory A superfamily conotoxins to facilitate the dietary shift to fish hunting and species radiation in this clade.
S. W. A. Himaya; Ai-Hua Jin; Brett Hamilton; Subash K. Rai; Paul Alewood; Richard J. Lewis. Venom duct origins of prey capture and defensive conotoxins in piscivorous Conus striatus. Scientific Reports 2021, 11, 1 -14.
AMA StyleS. W. A. Himaya, Ai-Hua Jin, Brett Hamilton, Subash K. Rai, Paul Alewood, Richard J. Lewis. Venom duct origins of prey capture and defensive conotoxins in piscivorous Conus striatus. Scientific Reports. 2021; 11 (1):1-14.
Chicago/Turabian StyleS. W. A. Himaya; Ai-Hua Jin; Brett Hamilton; Subash K. Rai; Paul Alewood; Richard J. Lewis. 2021. "Venom duct origins of prey capture and defensive conotoxins in piscivorous Conus striatus." Scientific Reports 11, no. 1: 1-14.
Chemical transfection is broadly used to transiently transfect mammalian cells, although often associated with cellular stress and membrane instability, which imposes challenges for most cellular assays, including high-throughput (HT) assays. In the current study, we compared the effectiveness of calcium phosphate, FuGENE and Lipofectamine 3000 to transiently express two key voltage-gated ion channels critical in pain pathways, CaV2.2 and NaV1.7. The expression and function of these channels were validated using two HT platforms, the Fluorescence Imaging Plate Reader FLIPRTetra and the automated patch clamp QPatch 16X. We found that all transfection methods tested demonstrated similar effectiveness when applied to FLIPRTetra assays. Lipofectamine 3000-mediated transfection produced the largest peak currents for automated patch clamp QPatch assays. However, the FuGENE-mediated transfection was the most effective for QPatch assays as indicated by the superior number of cells displaying GΩ seal formation in whole-cell patch clamp configuration, medium to large peak currents, and higher rates of accomplished assays for both CaV2.2 and NaV1.7 channels. Our findings can facilitate the development of HT automated patch clamp assays for the discovery and characterization of novel analgesics and modulators of pain pathways, as well as assisting studies examining the pharmacology of mutated channels.
Mahadhi Hasan; Lotten Ragnarsson; Fernanda C. Cardoso; Richard J. Lewis. Transfection methods for high-throughput cellular assays of voltage-gated calcium and sodium channels involved in pain. PLOS ONE 2021, 16, e0243645 .
AMA StyleMahadhi Hasan, Lotten Ragnarsson, Fernanda C. Cardoso, Richard J. Lewis. Transfection methods for high-throughput cellular assays of voltage-gated calcium and sodium channels involved in pain. PLOS ONE. 2021; 16 (3):e0243645.
Chicago/Turabian StyleMahadhi Hasan; Lotten Ragnarsson; Fernanda C. Cardoso; Richard J. Lewis. 2021. "Transfection methods for high-throughput cellular assays of voltage-gated calcium and sodium channels involved in pain." PLOS ONE 16, no. 3: e0243645.
The peripheral effects of ω-conotoxins, selective blockers of N-type voltage-gated calcium channels (CaV2.2), have not been characterised across different clinically relevant pain models. This study examines the effects of locally administered ω-conotoxin MVIIA, GVIA, and CVIF on mechanical and thermal paw withdrawal threshold (PWT) in postsurgical pain (PSP), cisplatin-induced neuropathy (CisIPN), and oxaliplatin-induced neuropathy (OIPN) rodent models. Intraplantar injection of 300, 100 and 30 nM MVIIA significantly (p < 0.0001, p < 0.0001, and p < 0.05, respectively) alleviated mechanical allodynia of mice in PSP model compared to vehicle control group. Similarly, intraplantar injection of 300, 100, and 30 nM MVIIA (p < 0.0001, p < 0.01, and p < 0.05, respectively), and 300 nM and 100 nM GVIA (p < 0.0001 and p < 0.05, respectively) significantly increased mechanical thresholds of mice in OIPN model. The ED50 of GVIA and MVIIA in OIPN was found to be 1.8 pmol/paw and 0.8 pmol/paw, respectively. However, none of the ω-conotoxins were effective in a mouse model of CisIPN. The intraplantar administration of 300 nM GVIA, MVIIA, and CVIF did not cause any locomotor side effects. The intraplantar administration of MVIIA can alleviate incision-induced mechanical allodynia, and GVIA and MVIIA effectively reduce OIPN associated mechanical pain, without locomotor side effects, in rodent models. In contrast, CVIF was inactive in these pain models, suggesting it is unable to block a subset of N-type voltage-gated calcium channels associated with nociceptors in the skin.
Mahadhi Hasan; Hana Starobova; Alexander Mueller; Irina Vetter; Richard Lewis. Subcutaneous ω-Conotoxins Alleviate Mechanical Pain in Rodent Models of Acute Peripheral Neuropathy. Marine Drugs 2021, 19, 106 .
AMA StyleMahadhi Hasan, Hana Starobova, Alexander Mueller, Irina Vetter, Richard Lewis. Subcutaneous ω-Conotoxins Alleviate Mechanical Pain in Rodent Models of Acute Peripheral Neuropathy. Marine Drugs. 2021; 19 (2):106.
Chicago/Turabian StyleMahadhi Hasan; Hana Starobova; Alexander Mueller; Irina Vetter; Richard Lewis. 2021. "Subcutaneous ω-Conotoxins Alleviate Mechanical Pain in Rodent Models of Acute Peripheral Neuropathy." Marine Drugs 19, no. 2: 106.
Conotoxins are disulfide-rich peptides found in the venom of cone snails. Due to their exquisite potency and high selectivity for a wide range of voltage and ligand gated ion channels they are attractive drug leads in neuropharmacology. Recently, cone snails were found to have the capability to rapidly switch between venom types with different proteome profiles in response to predatory or defensive stimuli. A novel conotoxin, GXIA (original name G117), belonging to the I3-subfamily was identified as the major component of the predatory venom of piscivorous Conus geographus. Using 2D solution NMR spectroscopy techniques, we resolved the 3D structure for GXIA, the first structure reported for the I3-subfamily and framework XI family. The 32 amino acid peptide is comprised of eight cysteine residues with the resultant disulfide connectivity forming an ICK+1 motif. With a triple stranded β-sheet, the GXIA backbone shows striking similarity to several tarantula toxins targeting the voltage sensor of voltage gated potassium and sodium channels. Supported by an amphipathic surface, the structural evidence suggests that GXIA is able to embed in the membrane and bind to the voltage sensor domain of a putative ion channel target.
David Armstrong; Ai-Hua Jin; Nayara Braga Emidio; Richard Lewis; Paul Alewood; K. Rosengren. Chemical Synthesis and NMR Solution Structure of Conotoxin GXIA from Conus geographus. Marine Drugs 2021, 19, 60 .
AMA StyleDavid Armstrong, Ai-Hua Jin, Nayara Braga Emidio, Richard Lewis, Paul Alewood, K. Rosengren. Chemical Synthesis and NMR Solution Structure of Conotoxin GXIA from Conus geographus. Marine Drugs. 2021; 19 (2):60.
Chicago/Turabian StyleDavid Armstrong; Ai-Hua Jin; Nayara Braga Emidio; Richard Lewis; Paul Alewood; K. Rosengren. 2021. "Chemical Synthesis and NMR Solution Structure of Conotoxin GXIA from Conus geographus." Marine Drugs 19, no. 2: 60.
The voltage-gated sodium channel Nav1.8 mediates the tetrodotoxin-resistant (TTX-R) Na+ current in nociceptive primary sensory neurons, which has an important role in the transmission of painful stimuli. Here, we describe the functional modulation of the human Nav1.8 α-subunit in Xenopus oocytes by auxiliary β subunits. We found that the β3 subunit down-regulated the maximal Na+ current amplitude and decelerated recovery from inactivation of hNav1.8, whereas the β1 and β2 subunits had no such effects. The specific regulation of Nav1.8 by the β3 subunit constitutes a potential novel regulatory mechanism of the TTX-R Na+ current in primary sensory neurons with potential implications in chronic pain states. In particular, neuropathic pain states are characterised by a down-regulation of Nav1.8 accompanied by increased expression of the β3 subunit. Our results suggest that these two phenomena may be correlated, and that increased levels of the β3 subunit may directly contribute to the down-regulation of Nav1.8. To determine which domain of the β3 subunit is responsible for the specific regulation of hNav1.8, we created chimeras of the β1 and β3 subunits and co-expressed them with the hNav1.8 α-subunit in Xenopus oocytes. The intracellular domain of the β3 subunit was shown to be responsible for the down-regulation of maximal Nav1.8 current amplitudes. In contrast, the extracellular domain mediated the effect of the β3 subunit on hNav1.8 recovery kinetics.
S. T. Nevin; N. Lawrence; A. Nicke; R. J. Lewis; D. J. Adams. Functional modulation of the human voltage-gated sodium channel NaV1.8 by auxiliary β subunits. Channels 2020, 15, 79 -93.
AMA StyleS. T. Nevin, N. Lawrence, A. Nicke, R. J. Lewis, D. J. Adams. Functional modulation of the human voltage-gated sodium channel NaV1.8 by auxiliary β subunits. Channels. 2020; 15 (1):79-93.
Chicago/Turabian StyleS. T. Nevin; N. Lawrence; A. Nicke; R. J. Lewis; D. J. Adams. 2020. "Functional modulation of the human voltage-gated sodium channel NaV1.8 by auxiliary β subunits." Channels 15, no. 1: 79-93.
Neuronal nicotinic acetylcholine receptors (nAChRs) are prototypical cation-selective, ligand-gated ion channels that mediate fast neurotransmission in the central and peripheral nervous systems. nAChRs are involved in a range of physiological and pathological functions and hence are important therapeutic targets. Their subunit homology and diverse pentameric assembly contribute to their challenging pharmacology and limit their drug development potential. Toxins produced by an extensive range of algae, plants and animals target nAChRs, with many proving pivotal in elucidating receptor pharmacology and biochemistry, as well as providing templates for structure-based drug design. The crystal structures of these toxins with diverse chemical profiles in complex with acetylcholine binding protein (AChBP), a soluble homolog of the extracellular ligand-binding domain of the nAChRs and more recently the extracellular domain of human α9 nAChRs, have been reported. These studies have shed light on the diverse molecular mechanisms of ligand-binding at neuronal nAChR subtypes and uncovered critical insights useful for rational drug design. This review provides a comprehensive overview and perspectives obtained from structure and function studies of diverse plant and animal toxins and their associated inhibitory mechanisms at neuronal nAChRs.
Thao N. T. Ho; Nikita Abraham; Richard J. Lewis. Structure-Function of Neuronal Nicotinic Acetylcholine Receptor Inhibitors Derived From Natural Toxins. Frontiers in Neuroscience 2020, 14, 1 .
AMA StyleThao N. T. Ho, Nikita Abraham, Richard J. Lewis. Structure-Function of Neuronal Nicotinic Acetylcholine Receptor Inhibitors Derived From Natural Toxins. Frontiers in Neuroscience. 2020; 14 ():1.
Chicago/Turabian StyleThao N. T. Ho; Nikita Abraham; Richard J. Lewis. 2020. "Structure-Function of Neuronal Nicotinic Acetylcholine Receptor Inhibitors Derived From Natural Toxins." Frontiers in Neuroscience 14, no. : 1.
Voltage-gated sodium (NaV) channel subtypes, including NaV1.7, are promising targets for the treatment of neurological diseases, such as chronic pain. Cone snail-derived µ-conotoxins are small, potent NaV channel inhibitors which represent potential drug leads. Of the 22 µ-conotoxins characterised so far, only a small number, including KIIIA and CnIIIC, have shown inhibition against human NaV1.7. We have recently identified a novel µ-conotoxin, SxIIIC, from Conus striolatus. Here we present the isolation of native peptide, chemical synthesis, characterisation of human NaV channel activity by whole-cell patch-clamp electrophysiology and analysis of the NMR solution structure. SxIIIC displays a unique NaV channel selectivity profile (1.4 > 1.3 > 1.1 ≈ 1.6 ≈ 1.7 > 1.2 >> 1.5 ≈ 1.8) when compared to other µ-conotoxins and represents one of the most potent human NaV1.7 putative pore blockers (IC50 152.2 ± 21.8 nM) to date. NMR analysis reveals the structure of SxIIIC includes the characteristic α-helix seen in other µ-conotoxins. Future investigations into structure-activity relationships of SxIIIC are expected to provide insights into residues important for NaV channel pore blocker selectivity and subsequently important for chronic pain drug development.
Kirsten L. McMahon; Hue N.T. Tran; Jennifer R. Deuis; Richard J. Lewis; Irina Vetter; Christina I. Schroeder. Discovery, Pharmacological Characterisation and NMR Structure of the Novel µ-Conotoxin SxIIIC, a Potent and Irreversible NaV Channel Inhibitor. Biomedicines 2020, 8, 391 .
AMA StyleKirsten L. McMahon, Hue N.T. Tran, Jennifer R. Deuis, Richard J. Lewis, Irina Vetter, Christina I. Schroeder. Discovery, Pharmacological Characterisation and NMR Structure of the Novel µ-Conotoxin SxIIIC, a Potent and Irreversible NaV Channel Inhibitor. Biomedicines. 2020; 8 (10):391.
Chicago/Turabian StyleKirsten L. McMahon; Hue N.T. Tran; Jennifer R. Deuis; Richard J. Lewis; Irina Vetter; Christina I. Schroeder. 2020. "Discovery, Pharmacological Characterisation and NMR Structure of the Novel µ-Conotoxin SxIIIC, a Potent and Irreversible NaV Channel Inhibitor." Biomedicines 8, no. 10: 391.
Australian funnel-web spiders are infamous for causing human fatalities, which are induced by venom peptides known as δ-hexatoxins (δ-HXTXs). Humans and other primates did not feature in the prey or predator spectrum during evolution of these spiders, and consequently the primate lethality of δ-HXTXs remains enigmatic. Funnel-web envenomations are mostly inflicted by male spiders that wander from their burrow in search of females during the mating season, which suggests a role for δ-HXTXs in self-defense since male spiders rarely feed during this period. Although 35 species of Australian funnel-web spiders have been described, only nine δ-HXTXs from four species have been characterized, resulting in a lack of understanding of the ecological roles and molecular evolution of δ-HXTXs. Here, by profiling venom-gland transcriptomes of 10 funnel-web species, we report 22 δ-HXTXs. Phylogenetic and evolutionary assessments reveal a remarkable sequence conservation of δ-HXTXs despite their deep evolutionary origin within funnel-web spiders, consistent with a defensive role. We demonstrate that δ-HXTX-Ar1a, the lethal toxin from the Sydney funnel-web spider Atrax robustus, induces pain in mice by inhibiting inactivation of voltage-gated sodium (NaV) channels involved in nociceptive signaling. δ-HXTX-Ar1a also inhibited inactivation of cockroach NaV channels and was insecticidal to sheep blowflies. Considering their algogenic effects in mice, potent insecticidal effects, and high levels of sequence conservation, we propose that the δ-HXTXs were repurposed from an initial insecticidal predatory function to a role in defending against nonhuman vertebrate predators by male spiders, with their lethal effects on humans being an unfortunate evolutionary coincidence.
Volker Herzig; Kartik Sunagar; David T. R. Wilson; Sandy S. Pineda; Mathilde R. Israel; Sebastien Dutertre; Brianna Sollod McFarland; Eivind A. B. Undheim; Wayne C. Hodgson; Paul F. Alewood; Richard J. Lewis; Frank Bosmans; Irina Vetter; Glenn F. King; Bryan G. Fry. Australian funnel-web spiders evolved human-lethal δ-hexatoxins for defense against vertebrate predators. Proceedings of the National Academy of Sciences 2020, 117, 24920 -24928.
AMA StyleVolker Herzig, Kartik Sunagar, David T. R. Wilson, Sandy S. Pineda, Mathilde R. Israel, Sebastien Dutertre, Brianna Sollod McFarland, Eivind A. B. Undheim, Wayne C. Hodgson, Paul F. Alewood, Richard J. Lewis, Frank Bosmans, Irina Vetter, Glenn F. King, Bryan G. Fry. Australian funnel-web spiders evolved human-lethal δ-hexatoxins for defense against vertebrate predators. Proceedings of the National Academy of Sciences. 2020; 117 (40):24920-24928.
Chicago/Turabian StyleVolker Herzig; Kartik Sunagar; David T. R. Wilson; Sandy S. Pineda; Mathilde R. Israel; Sebastien Dutertre; Brianna Sollod McFarland; Eivind A. B. Undheim; Wayne C. Hodgson; Paul F. Alewood; Richard J. Lewis; Frank Bosmans; Irina Vetter; Glenn F. King; Bryan G. Fry. 2020. "Australian funnel-web spiders evolved human-lethal δ-hexatoxins for defense against vertebrate predators." Proceedings of the National Academy of Sciences 117, no. 40: 24920-24928.
Chronic pain is a serious debilitating condition that affects ∼20% of the world's population. Currently available drugs fail to produce effective pain relief in many patients and have dose-limiting side effects. Several voltage-gated sodium (NaV) and calcium (CaV) channels are implicated in the etiology of chronic pain, particularly NaV1.1, NaV1.3, NaV1.7–NaV1.9, CaV2.2, and CaV3.2. Numerous NaV and CaV modulators have been described, but with few exceptions, they display poor potency and/or selectivity for pain-related channel subtypes. Here, we report the discovery and characterization of 2 novel tarantula-venom peptides (Tap1a and Tap2a) isolated from Theraphosa apophysis venom that modulate the activity of both NaV and CaV3 channels. Tap1a and Tap2a inhibited on-target NaV and CaV3 channels at nanomolar to micromolar concentrations and displayed moderate off-target selectivity for NaV1.6 and weak affinity for NaV1.4 and NaV1.5. The most potent inhibitor, Tap1a, nearly ablated neuronal mechanosensitivity in afferent fibers innervating the colon and the bladder, with in vivo intracolonic administration reversing colonic mechanical hypersensitivity in a mouse model of irritable bowel syndrome. These findings suggest that targeting a specific combination of NaV and CaV3 subtypes provides a novel route for treatment of chronic visceral pain.
Fernanda C. Cardoso; Joel Castro; Luke Grundy; Gudrun Schober; Sonia Garcia-Caraballo; Tianjiao Zhao; Volker Herzig; Glenn F. King; Stuart M. Brierley; Richard J. Lewis. A spider-venom peptide with multitarget activity on sodium and calcium channels alleviates chronic visceral pain in a model of irritable bowel syndrome. Pain 2020, 162, 569 -581.
AMA StyleFernanda C. Cardoso, Joel Castro, Luke Grundy, Gudrun Schober, Sonia Garcia-Caraballo, Tianjiao Zhao, Volker Herzig, Glenn F. King, Stuart M. Brierley, Richard J. Lewis. A spider-venom peptide with multitarget activity on sodium and calcium channels alleviates chronic visceral pain in a model of irritable bowel syndrome. Pain. 2020; 162 (2):569-581.
Chicago/Turabian StyleFernanda C. Cardoso; Joel Castro; Luke Grundy; Gudrun Schober; Sonia Garcia-Caraballo; Tianjiao Zhao; Volker Herzig; Glenn F. King; Stuart M. Brierley; Richard J. Lewis. 2020. "A spider-venom peptide with multitarget activity on sodium and calcium channels alleviates chronic visceral pain in a model of irritable bowel syndrome." Pain 162, no. 2: 569-581.
Ciguatera fish poisoning (CFP) is caused by the consumption of fish contaminated with ciguatoxins (CTXs). The most distressing symptoms are cutaneous sensory disturbances, including cold dysesthesia and itch. CTXs are neurotoxins known to activate voltage-gated sodium channels (Nav) but no specific treatment exists. Peptidergic neurons have been critically involved in CFP sensory disturbances. Protease-activated receptor-2 (PAR2) is an itch- and pain- related G protein-coupled receptor whose activation leads to a calcium-dependent neuropeptide release. Here, we studied the role of Nav, PAR2 and the PAR2 agonist cathepsin S (Cat-S) in the cytosolic calcium increase and subsequent release of the neuropeptide substance P (SP) elicited by Pacific ciguatoxin-2 (P-CTX-2) in rat sensory neurons and human epidermal keratinocytes. In sensory neurons, the P-CTX-2-evoked calcium response was driven by Nav- and PAR2-dependent mechanisms. In keratinocytes, P-CTX-2 also induced a Nav- and PAR2-dependent marked calcium response. In the co-cultured cells, P-CTX-2 significantly increased Cat-S activity, and Cat-S and PAR2 antagonists almost abolished P-CTX-2-elicited SP release. Keratinocytes synergistically favored the induced SP release. Our results demonstrate that the sensory effects of CTXs involve the Cat-S-PAR2 pathway and are potentiated by their direct action on non-excitable keratinocytes through the same pathway.
Killian L’Herondelle; Ophelie Pierre; Sophie Fouyet; Raphael Leschiera; Christelle Le Gall-Ianotto; Reginald Philippe; Paul Buscaglia; Olivier Mignen; Matthieu Talagas; Richard J. Lewis; Laurence Michel; Laurent Misery; Raphaele Le Garrec. PAR2, Keratinocytes, and Cathepsin S Mediate the Sensory Effects of Ciguatoxins Responsible for Ciguatera Poisoning. Journal of Investigative Dermatology 2020, 141, 648 -658.e3.
AMA StyleKillian L’Herondelle, Ophelie Pierre, Sophie Fouyet, Raphael Leschiera, Christelle Le Gall-Ianotto, Reginald Philippe, Paul Buscaglia, Olivier Mignen, Matthieu Talagas, Richard J. Lewis, Laurence Michel, Laurent Misery, Raphaele Le Garrec. PAR2, Keratinocytes, and Cathepsin S Mediate the Sensory Effects of Ciguatoxins Responsible for Ciguatera Poisoning. Journal of Investigative Dermatology. 2020; 141 (3):648-658.e3.
Chicago/Turabian StyleKillian L’Herondelle; Ophelie Pierre; Sophie Fouyet; Raphael Leschiera; Christelle Le Gall-Ianotto; Reginald Philippe; Paul Buscaglia; Olivier Mignen; Matthieu Talagas; Richard J. Lewis; Laurence Michel; Laurent Misery; Raphaele Le Garrec. 2020. "PAR2, Keratinocytes, and Cathepsin S Mediate the Sensory Effects of Ciguatoxins Responsible for Ciguatera Poisoning." Journal of Investigative Dermatology 141, no. 3: 648-658.e3.
Structural modifications of the neuronal calcium channel blocker MONIRO-1, including constraining the phenoxyaniline portion of the molecule and replacing the guanidinium functionality with tertiary amines, led to compounds with significantly improved affinities for the endogenously expressed CaV2.2 channel in the SH-SY5Y neuroblastoma cell line. These analogues also showed promising activity towards the CaV3.2 channel, recombinantly expressed in HEK293T cells. Both of these ion channels have received attention as likely targets for the treatment of neuropathic pain. The dibenzoazepine and dihydrobenzodiazepine derivatives prepared in this study show an encouraging combination of neuronal calcium ion channel inhibitory potency, plasma stability and potential to cross the blood–brain-barrier.
Fernanda C. Cardoso; Marie-Adeline Marliac; Chloe Geoffroy; Matthieu Schmit; Anjie Bispat; Richard Lewis; Kellie L. Tuck; Peter J. Duggan. The neuronal calcium ion channel activity of constrained analogues of MONIRO-1. Bioorganic & Medicinal Chemistry 2020, 28, 115655 .
AMA StyleFernanda C. Cardoso, Marie-Adeline Marliac, Chloe Geoffroy, Matthieu Schmit, Anjie Bispat, Richard Lewis, Kellie L. Tuck, Peter J. Duggan. The neuronal calcium ion channel activity of constrained analogues of MONIRO-1. Bioorganic & Medicinal Chemistry. 2020; 28 (18):115655.
Chicago/Turabian StyleFernanda C. Cardoso; Marie-Adeline Marliac; Chloe Geoffroy; Matthieu Schmit; Anjie Bispat; Richard Lewis; Kellie L. Tuck; Peter J. Duggan. 2020. "The neuronal calcium ion channel activity of constrained analogues of MONIRO-1." Bioorganic & Medicinal Chemistry 28, no. 18: 115655.
The 27-amino acid (aa)-long d-conotoxin TxVIA, originally isolated from the mollusc-hunting cone snail Conus textile, slows voltage-gated sodium (NaV) channel inactivation in molluscan neurons, but its mammalian ion channel targets remain undetermined. In this study, we confirmed that TxVIA was inactive on mammalian NaV1.2 and NaV1.7 even at high concentrations (10 µM). Given the fact that invertebrate NaV channel and T-type calcium channels (CaV3.x) are evolutionarily related, we examined the possibility that TxVIA may act on CaV3.x. Electrophysiological characterisation of the native TxVIA on CaV3.1, 3.2 and 3.3 revealed that TxVIA preferentially inhibits CaV3.2 current (IC50 = 0.24 mM) and enhances CaV3.1 current at higher concentrations. In fish bioassays TxVIA showed little effect on zebrafish behaviours when injected intramuscular at 250 ng/100 mg fish. The binding sites for TxVIA at NaV1.7 and CaV3.1 revealed that their channel binding sites contained a common epitope.
Dan Wang; S.W.A. Himaya; Jean Giacomotto; Mahadhi Hasan; Fernanda C. Cardoso; Lotten Ragnarsson; Richard J. Lewis. Characterisation of d-Conotoxin TxVIA as a Mammalian T-Type Calcium Channel Modulator. Marine Drugs 2020, 18, 343 .
AMA StyleDan Wang, S.W.A. Himaya, Jean Giacomotto, Mahadhi Hasan, Fernanda C. Cardoso, Lotten Ragnarsson, Richard J. Lewis. Characterisation of d-Conotoxin TxVIA as a Mammalian T-Type Calcium Channel Modulator. Marine Drugs. 2020; 18 (7):343.
Chicago/Turabian StyleDan Wang; S.W.A. Himaya; Jean Giacomotto; Mahadhi Hasan; Fernanda C. Cardoso; Lotten Ragnarsson; Richard J. Lewis. 2020. "Characterisation of d-Conotoxin TxVIA as a Mammalian T-Type Calcium Channel Modulator." Marine Drugs 18, no. 7: 343.
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 (NaV) channel 1.7 (NaV1.7), which has been identified as a primary pain target. However, in developing NaV1.7-targeted analgesics, extreme care must to be taken to avoid off-target activity on other NaV subtypes that are critical for survival. Since spider venoms are an excellent source of NaV channel modulators, we screened a panel of spider venoms to identify selective NaV1.7 inhibitors. This led to identification of two novel NaV 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 NaV1.7 pharmacophore of ProTx-I. We designed several ProTx-I and Pe1b analogues, and tested them for activity and NaV channel subtype selectivity. Several analogues had improved potency against NaV1.7, and altered specificity against other NaV channels. These analogues provide a foundation for development of Pe1b as a lead molecule for therapeutic inhibition of NaV1.7.
Darshani B. Rupasinghe; Volker Herzig; Irina Vetter; Zoltan Dekan; John Gilchrist; Frank Bosmans; Paul F. Alewood; Richard J. Lewis; Glenn F. King. 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. Biochemical Pharmacology 2020, 181, 114080 .
AMA StyleDarshani B. Rupasinghe, Volker Herzig, Irina Vetter, Zoltan Dekan, John Gilchrist, Frank Bosmans, Paul F. Alewood, Richard J. Lewis, Glenn F. King. 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. Biochemical Pharmacology. 2020; 181 ():114080.
Chicago/Turabian StyleDarshani B. Rupasinghe; Volker Herzig; Irina Vetter; Zoltan Dekan; John Gilchrist; Frank Bosmans; Paul F. Alewood; Richard J. Lewis; Glenn F. King. 2020. "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." Biochemical Pharmacology 181, no. : 114080.
Low Voltage-Activated (LVA) T-type calcium channels are characterized by transient current and Low Threshold Spikes (LTS) that trigger neuronal firing and oscillatory behavior. Combined with their preferential localization in dendrites and their specific “window current”, T-type calcium channels are considered to be key players in signal amplification and synaptic integration. Assisted by the emerging pharmacological tools, the structural determinants of channel gating and kinetics, as well as novel physiological and pathological functions of T-type calcium channels, are being uncovered. In this review, we provide an overview of structural determinants in T-type calcium channels, their involvement in disorders and diseases, the development of novel channel modulators, as well as Structure-Activity Relationship (SAR) studies that lead to rational drug design.
Lotten Ragnarsson; Richard J. Lewis; Dan Wang. T-type Calcium Channels in Health and Disease. Current Medicinal Chemistry 2020, 27, 3098 -3122.
AMA StyleLotten Ragnarsson, Richard J. Lewis, Dan Wang. T-type Calcium Channels in Health and Disease. Current Medicinal Chemistry. 2020; 27 (19):3098-3122.
Chicago/Turabian StyleLotten Ragnarsson; Richard J. Lewis; Dan Wang. 2020. "T-type Calcium Channels in Health and Disease." Current Medicinal Chemistry 27, no. 19: 3098-3122.
Conopeptides are neurotoxic peptides in the venom of marine cone snails and have broad therapeutic potential for managing pain and other conditions. Here, we identified the single-disulfide peptides Czon1107 and Cca1669 from the venoms of Conus zonatus and Conus caracteristicus, respectively. We observed that Czon1107 strongly inhibits the human α3β4 (IC50 15.7 ± 3.0 μM) and α7 (IC50 77.1 ± 0.05 μM) nicotinic acetylcholine receptor (nAChR) subtypes, but the activity of Cca1669 remains to be identified. Czon1107 acted at a site distinct from the orthosteric receptor site. Solution NMR experiments revealed that Czon1107 exists in equilibrium between conformational states that are the result of a key Ser4–Pro5 cis–trans isomerization. Moreover, we found that the X-Pro amide bonds in the inter-cysteine loop are rigidly constrained to cis conformations. Structure–activity experiments of Czon1107 and its variants at positions P5 and P7 revealed that the conformation around the X-Pro bonds (cis–trans) plays an important role in receptor subtype selectivity. The cis conformation at the Cys6–Pro7 peptide bond was essential for α3β4 nAChR subtype allosteric selectivity. In summary, we have identified an unique single disulfide conopeptide with a non-competitive, potentially allosteric inhibitory mechanism at the nAChRs. The small size and rigidity of the Czon1107 peptide could provide a scaffold for rational drug design strategies for allosteric nAChR modulation. This new paradigm in the “conotoxinomic” structure–function space provides an impetus to screen venom from other Conus species for similar, short bioactive peptides that allosterically modulate ligand-gated receptor function.
Madhan Kumar Mohan; Nikita Abraham; Rajesh R P; Benjamin Franklin Jayaseelan; Lotten Ragnarsson; Richard J. Lewis; Siddhartha P. Sarma. Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3β4 and α7 nicotinic acetylcholine receptors. Journal of Biological Chemistry 2020, 295, 7096 -7112.
AMA StyleMadhan Kumar Mohan, Nikita Abraham, Rajesh R P, Benjamin Franklin Jayaseelan, Lotten Ragnarsson, Richard J. Lewis, Siddhartha P. Sarma. Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3β4 and α7 nicotinic acetylcholine receptors. Journal of Biological Chemistry. 2020; 295 (20):7096-7112.
Chicago/Turabian StyleMadhan Kumar Mohan; Nikita Abraham; Rajesh R P; Benjamin Franklin Jayaseelan; Lotten Ragnarsson; Richard J. Lewis; Siddhartha P. Sarma. 2020. "Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3β4 and α7 nicotinic acetylcholine receptors." Journal of Biological Chemistry 295, no. 20: 7096-7112.
Manuel A. Fernandez-Rojo; Andreas Brust; Jeremy Potriquet; Joshua Daley; Lotten Ragnarsson; Asa Andersson; Pamela Mukhopadhyay; Patrick Wilhelm; Yanni Chin; Taylor Smallwood; Richard Clark; Glenn King; Grant Ramm; Nic Waddell; Richard Lewis; Glen Boyle; Bryan Fry; Paul Alewood; Jason Mulvenna; John Miles; Maria P. Ikonomopoulou. The antiproliferative profile of a linear octopus-derived peptide in melanoma of BRAF-mutation. Toxicon 2020, 177, S2 .
AMA StyleManuel A. Fernandez-Rojo, Andreas Brust, Jeremy Potriquet, Joshua Daley, Lotten Ragnarsson, Asa Andersson, Pamela Mukhopadhyay, Patrick Wilhelm, Yanni Chin, Taylor Smallwood, Richard Clark, Glenn King, Grant Ramm, Nic Waddell, Richard Lewis, Glen Boyle, Bryan Fry, Paul Alewood, Jason Mulvenna, John Miles, Maria P. Ikonomopoulou. The antiproliferative profile of a linear octopus-derived peptide in melanoma of BRAF-mutation. Toxicon. 2020; 177 ():S2.
Chicago/Turabian StyleManuel A. Fernandez-Rojo; Andreas Brust; Jeremy Potriquet; Joshua Daley; Lotten Ragnarsson; Asa Andersson; Pamela Mukhopadhyay; Patrick Wilhelm; Yanni Chin; Taylor Smallwood; Richard Clark; Glenn King; Grant Ramm; Nic Waddell; Richard Lewis; Glen Boyle; Bryan Fry; Paul Alewood; Jason Mulvenna; John Miles; Maria P. Ikonomopoulou. 2020. "The antiproliferative profile of a linear octopus-derived peptide in melanoma of BRAF-mutation." Toxicon 177, no. : S2.
Mriga Dutt; Jean Giacomotto; Lotten Ragnarsson; Asa Andersson; Andreas Brust; Zoltan Deakan; Paul F. Alewood; Richard Lewis. Re-evaluating the nirvana cabal deployed by piscivorous cone snails. Toxicon 2020, 177, S9 -S10.
AMA StyleMriga Dutt, Jean Giacomotto, Lotten Ragnarsson, Asa Andersson, Andreas Brust, Zoltan Deakan, Paul F. Alewood, Richard Lewis. Re-evaluating the nirvana cabal deployed by piscivorous cone snails. Toxicon. 2020; 177 ():S9-S10.
Chicago/Turabian StyleMriga Dutt; Jean Giacomotto; Lotten Ragnarsson; Asa Andersson; Andreas Brust; Zoltan Deakan; Paul F. Alewood; Richard Lewis. 2020. "Re-evaluating the nirvana cabal deployed by piscivorous cone snails." Toxicon 177, no. : S9-S10.