1
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Budusan E, Payne CD, Gonzalez TI, Obergrussberger A, Becker N, Clark RJ, Johan Rosengren K, Rash LD, Cristofori-Armstrong B. The funnel-web spider venom derived single knot peptide Hc3a modulates acid-sensing ion channel 1a desensitisation. Biochem Pharmacol 2024:116175. [PMID: 38552850 DOI: 10.1016/j.bcp.2024.116175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 03/17/2024] [Accepted: 03/26/2024] [Indexed: 04/07/2024]
Abstract
Acid-sensing ion channel 1a (ASIC1a) is a proton-gated channel involved in synaptic transmission, pain signalling, and several ischemia-associated pathological conditions. The spider venom-derived peptides PcTx1 and Hi1a are two of the most potent ASIC1a inhibitors known and have been instrumental in furthering our understanding of the structure, function, and biological roles of ASICs. To date, homologous spider peptides with different pharmacological profiles at ASIC1a have yet to be discovered. Here we report the characterisation of Hc3a, a single inhibitor cystine knot peptide from the Australian funnel-web spider Hadronyche cerberea with sequence similarity to PcTx1. We show that Hc3a has complex pharmacology and binds different ASIC1a conformational states (closed, open, and desensitised) with different affinities, with the most prominent effect on desensitisation. Hc3a slows the desensitisation kinetics of proton-activated ASIC1a currents across multiple application pHs, and when bound directly to ASIC1a in the desensitised conformation promotes current inhibition. The solution structure of Hc3a was solved, and the peptide-channel interaction examined via mutagenesis studies to highlight how small differences in sequence between Hc3a and PcTx1 can lead to peptides with distinct pharmacology. The discovery of Hc3a expands the pharmacological diversity of spider venom peptides targeting ASIC1a and adds to the toolbox of compounds to study the intricacies of ASIC1 gating.
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Affiliation(s)
- Elena Budusan
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Colton D Payne
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Tye I Gonzalez
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
| | | | | | - Richard J Clark
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - K Johan Rosengren
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia.
| | - Lachlan D Rash
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia.
| | - Ben Cristofori-Armstrong
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, Australia.
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2
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Jami S, Deuis JR, Klasfauseweh T, Cheng X, Kurdyukov S, Chung F, Okorokov AL, Li S, Zhang J, Cristofori-Armstrong B, Israel MR, Ju RJ, Robinson SD, Zhao P, Ragnarsson L, Andersson Å, Tran P, Schendel V, McMahon KL, Tran HNT, Chin YKY, Zhu Y, Liu J, Crawford T, Purushothamvasan S, Habib AM, Andersson DA, Rash LD, Wood JN, Zhao J, Stehbens SJ, Mobli M, Leffler A, Jiang D, Cox JJ, Waxman SG, Dib-Hajj SD, Neely GG, Durek T, Vetter I. Pain-causing stinging nettle toxins target TMEM233 to modulate Na V1.7 function. Nat Commun 2023; 14:2442. [PMID: 37117223 PMCID: PMC10147923 DOI: 10.1038/s41467-023-37963-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/08/2023] [Indexed: 04/30/2023] Open
Abstract
Voltage-gated sodium (NaV) channels are critical regulators of neuronal excitability and are targeted by many toxins that directly interact with the pore-forming α subunit, typically via extracellular loops of the voltage-sensing domains, or residues forming part of the pore domain. Excelsatoxin A (ExTxA), a pain-causing knottin peptide from the Australian stinging tree Dendrocnide excelsa, is the first reported plant-derived NaV channel modulating peptide toxin. Here we show that TMEM233, a member of the dispanin family of transmembrane proteins expressed in sensory neurons, is essential for pharmacological activity of ExTxA at NaV channels, and that co-expression of TMEM233 modulates the gating properties of NaV1.7. These findings identify TMEM233 as a previously unknown NaV1.7-interacting protein, position TMEM233 and the dispanins as accessory proteins that are indispensable for toxin-mediated effects on NaV channel gating, and provide important insights into the function of NaV channels in sensory neurons.
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Affiliation(s)
- Sina Jami
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Jennifer R Deuis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Tabea Klasfauseweh
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Xiaoyang Cheng
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Sergey Kurdyukov
- Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre, Centenary Institute, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Felicity Chung
- Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre, Centenary Institute, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Andrei L Okorokov
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, UK
| | - Shengnan Li
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, UK
| | - Jiangtao Zhang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, P.R. China
| | - Ben Cristofori-Armstrong
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Mathilde R Israel
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience, King's College London, SE1 1UL, London, UK
| | - Robert J Ju
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Samuel D Robinson
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Peng Zhao
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Lotten Ragnarsson
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Åsa Andersson
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Poanna Tran
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Vanessa Schendel
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Kirsten L McMahon
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Hue N T Tran
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Yanni K-Y Chin
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Yifei Zhu
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Junyu Liu
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Theo Crawford
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia
| | | | - Abdella M Habib
- College of Medicine, QU Health, Qatar University, PO Box 2713, Doha, Qatar
| | - David A Andersson
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience, King's College London, SE1 1UL, London, UK
| | - Lachlan D Rash
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - John N Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, UK
| | - Jing Zhao
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, UK
| | - Samantha J Stehbens
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Mehdi Mobli
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Andreas Leffler
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, 30625, Germany
| | - Daohua Jiang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, P.R. China
| | - James J Cox
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, UK
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Sulayman D Dib-Hajj
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - G Gregory Neely
- Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre, Centenary Institute, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Thomas Durek
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, St Lucia, QLD, 4072, Australia.
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD, 4102, Australia.
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Miller AN, Houlihan PR, Matamala E, Cabezas-Bratesco D, Lee GY, Cristofori-Armstrong B, Dilan TL, Sanchez-Martinez S, Matthies D, Yan R, Yu Z, Ren D, Brauchi SE, Clapham DE. The SARS-CoV-2 accessory protein Orf3a is not an ion channel, but does interact with trafficking proteins. eLife 2023; 12:e84477. [PMID: 36695574 PMCID: PMC9910834 DOI: 10.7554/elife.84477] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/25/2023] [Indexed: 01/26/2023] Open
Abstract
The severe acute respiratory syndrome associated coronavirus 2 (SARS-CoV-2) and SARS-CoV-1 accessory protein Orf3a colocalizes with markers of the plasma membrane, endocytic pathway, and Golgi apparatus. Some reports have led to annotation of both Orf3a proteins as viroporins. Here, we show that neither SARS-CoV-2 nor SARS-CoV-1 Orf3a form functional ion conducting pores and that the conductances measured are common contaminants in overexpression and with high levels of protein in reconstitution studies. Cryo-EM structures of both SARS-CoV-2 and SARS-CoV-1 Orf3a display a narrow constriction and the presence of a positively charged aqueous vestibule, which would not favor cation permeation. We observe enrichment of the late endosomal marker Rab7 upon SARS-CoV-2 Orf3a overexpression, and co-immunoprecipitation with VPS39. Interestingly, SARS-CoV-1 Orf3a does not cause the same cellular phenotype as SARS-CoV-2 Orf3a and does not interact with VPS39. To explain this difference, we find that a divergent, unstructured loop of SARS-CoV-2 Orf3a facilitates its binding with VPS39, a HOPS complex tethering protein involved in late endosome and autophagosome fusion with lysosomes. We suggest that the added loop enhances SARS-CoV-2 Orf3a's ability to co-opt host cellular trafficking mechanisms for viral exit or host immune evasion.
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Affiliation(s)
| | | | - Ella Matamala
- Physiology Institute and Millennium Nucleus of Ion Channel-Associated Diseases, Universidad Austral de ChileValdiviaChile
| | - Deny Cabezas-Bratesco
- Physiology Institute and Millennium Nucleus of Ion Channel-Associated Diseases, Universidad Austral de ChileValdiviaChile
| | - Gi Young Lee
- Department of Biology, University of PennsylvaniaPhiladelphiaUnited States
| | | | | | | | | | - Rui Yan
- Janelia Research CampusAshburnUnited States
| | - Zhiheng Yu
- Janelia Research CampusAshburnUnited States
| | - Dejian Ren
- Department of Biology, University of PennsylvaniaPhiladelphiaUnited States
| | - Sebastian E Brauchi
- Janelia Research CampusAshburnUnited States
- Physiology Institute and Millennium Nucleus of Ion Channel-Associated Diseases, Universidad Austral de ChileValdiviaChile
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4
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Miller AN, Houlihan PR, Matamala E, Cabezas-Bratesco D, Lee GY, Cristofori-Armstrong B, Dilan TL, Sanchez-Martinez S, Matthies D, Yan R, Yu Z, Ren D, Brauchi SE, Clapham DE. The SARS-CoV-2 accessory protein Orf3a is not an ion channel, but does interact with trafficking proteins. bioRxiv 2022:2022.09.02.506428. [PMID: 36263072 PMCID: PMC9580380 DOI: 10.1101/2022.09.02.506428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The severe acute respiratory syndrome associated coronavirus 2 (SARS-CoV-2) and SARS-CoV-1 accessory protein Orf3a colocalizes with markers of the plasma membrane, endocytic pathway, and Golgi apparatus. Some reports have led to annotation of both Orf3a proteins as a viroporin. Here we show that neither SARS-CoV-2 nor SARS-CoV-1 form functional ion conducting pores and that the conductances measured are common contaminants in overexpression and with high levels of protein in reconstitution studies. Cryo-EM structures of both SARS-CoV-2 and SARS-CoV-1 Orf3a display a narrow constriction and the presence of a basic aqueous vestibule, which would not favor cation permeation. We observe enrichment of the late endosomal marker Rab7 upon SARS-CoV-2 Orf3a overexpression, and co-immunoprecipitation with VPS39. Interestingly, SARS-CoV-1 Orf3a does not cause the same cellular phenotype as SARS-CoV-2 Orf3a and does not interact with VPS39. To explain this difference, we find that a divergent, unstructured loop of SARS-CoV-2 Orf3a facilitates its binding with VPS39, a HOPS complex tethering protein involved in late endosome and autophagosome fusion with lysosomes. We suggest that the added loop enhances SARS-CoV-2 Orf3a ability to co-opt host cellular trafficking mechanisms for viral exit or host immune evasion.
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5
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Bulumulla C, Krasley AT, Cristofori-Armstrong B, Valinsky WC, Walpita D, Ackerman D, Clapham DE, Beyene AG. Visualizing synaptic dopamine efflux with a 2D composite nanofilm. eLife 2022; 11:78773. [PMID: 35786443 PMCID: PMC9363124 DOI: 10.7554/elife.78773] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 07/01/2022] [Indexed: 11/23/2022] Open
Abstract
Chemical neurotransmission constitutes one of the fundamental modalities of communication between neurons. Monitoring release of these chemicals has traditionally been difficult to carry out at spatial and temporal scales relevant to neuron function. To understand chemical neurotransmission more fully, we need to improve the spatial and temporal resolutions of measurements for neurotransmitter release. To address this, we engineered a chemi-sensitive, two-dimensional composite nanofilm that facilitates visualization of the release and diffusion of the neurochemical dopamine with synaptic resolution, quantal sensitivity, and simultaneously from hundreds of release sites. Using this technology, we were able to monitor the spatiotemporal dynamics of dopamine release in dendritic processes, a poorly understood phenomenon. We found that dopamine release is broadcast from a subset of dendritic processes as hotspots that have a mean spatial spread of ≈ 3.2 µm (full width at half maximum [FWHM]) and are observed with a mean spatial frequency of one hotspot per ≈ 7.5 µm of dendritic length. Major dendrites of dopamine neurons and fine dendritic processes, as well as dendritic arbors and dendrites with no apparent varicose morphology participated in dopamine release. Remarkably, these release hotspots co-localized with Bassoon, suggesting that Bassoon may contribute to organizing active zones in dendrites, similar to its role in axon terminals. To form the vast and complex network necessary for an organism to sense and react to the world, neurons must connect at highly specialized junctions. Individual cells communicate at these ‘synapses’ by releasing chemical signals (or neurotransmitters) such as dopamine, a molecule involved in learning and motivation. Despite the central role that synapses play in the brain, it remains challenging to measure exactly where neurotransmitters are released and how far they travel from their release site. Currently, most tools available to scientists only allow bulk measurements of neurotransmitter release. To tackle this limitation, Bulumulla et al. developed a new way to measure neurotransmitter release from neurons, harnessing a technique which uses fluorescent nanosensors that glow brighter when exposed to dopamine. These sensors form a very thin film upon which neurons can grow; when the cells release dopamine, the sensors ‘light up’ as they encounter the molecule. Dubbed DopaFilm, the technology reveals exactly where the neurotransmitter comes from and how it spreads between cells in real time. In particular, the approach showed that dopamine emerges from 'hot spots' at specific sites in cells; it also helped Bulumulla et al. study how dopamine is released from subcellular compartments that have previously not been well characterized. Improving the sensors so that the film could detect other neurotransmitters besides dopamine would broaden the use of this approach. In the future, combining this technology with other types of imaging should enable studies of individual synapses with intricate detail.
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6
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Smallwood TB, Navarro S, Cristofori-Armstrong B, Watkins TS, Tungatt K, Ryan RYM, Haigh OL, Lutzky VP, Mulvenna JP, Rosengren KJ, Loukas A, Miles JJ, Clark RJ. Synthetic hookworm-derived peptides are potent modulators of primary human immune cell function that protect against experimental colitis in vivo. J Biol Chem 2021; 297:100834. [PMID: 34051231 PMCID: PMC8239465 DOI: 10.1016/j.jbc.2021.100834] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
The prevalence of autoimmune diseases is on the rise globally. Currently, autoimmunity presents in over 100 different forms and affects around 9% of the world's population. Current treatments available for autoimmune diseases are inadequate, expensive, and tend to focus on symptom management rather than cure. Clinical trials have shown that live helminthic therapy can decrease chronic inflammation associated with inflammatory bowel disease and other gastrointestinal autoimmune inflammatory conditions. As an alternative and better controlled approach to live infection, we have identified and characterized two peptides, Acan1 and Nak1, from the excretory/secretory component of parasitic hookworms for their therapeutic activity on experimental colitis. We synthesized Acan1 and Nak1 peptides from the Ancylostoma caninum and Necator americanus hookworms and assessed their structures and protective properties in human cell-based assays and in a mouse model of acute colitis. Acan1 and Nak1 displayed anticolitic properties via significantly reducing weight loss and colon atrophy, edema, ulceration, and necrosis in 2,4,6-trinitrobenzene sulfonic acid-exposed mice. These hookworm peptides prevented mucosal loss of goblet cells and preserved intestinal architecture. Acan1 upregulated genes responsible for the repair and restitution of ulcerated epithelium, whereas Nak1 downregulated genes responsible for epithelial cell migration and apoptotic cell signaling within the colon. These peptides were nontoxic and displayed key immunomodulatory functions in human peripheral blood mononuclear cells by suppressing CD4+ T cell proliferation and inhibiting IL-2 and TNF production. We conclude that Acan1 and Nak1 warrant further development as therapeutics for the treatment of autoimmunity, particularly gastrointestinal inflammatory conditions.
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Affiliation(s)
- Taylor B Smallwood
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, QLD, Australia
| | - Severine Navarro
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Woolworths Centre for Child Nutrition Research, Institute of Health and Biomedical Innovation, Queensland University of Technology, QLD, Australia
| | - Ben Cristofori-Armstrong
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, QLD, Australia
| | - Thomas S Watkins
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia
| | - Katie Tungatt
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, QLD, Australia
| | - Rachael Y M Ryan
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia
| | - Oscar L Haigh
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Viviana P Lutzky
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Jason P Mulvenna
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - K Johan Rosengren
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, QLD, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia
| | - John J Miles
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Centre for Molecular Therapeutics, The Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Australia; Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, QLD, Australia; Institute of Infection and Immunity, Cardiff University School of Medicine, University Hospital, Cardiff, Wales, United Kingdom.
| | - Richard J Clark
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, QLD, Australia.
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Herzig V, Cristofori-Armstrong B, Israel MR, Nixon SA, Vetter I, King GF. Animal toxins - Nature's evolutionary-refined toolkit for basic research and drug discovery. Biochem Pharmacol 2020; 181:114096. [PMID: 32535105 PMCID: PMC7290223 DOI: 10.1016/j.bcp.2020.114096] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/06/2020] [Accepted: 06/09/2020] [Indexed: 12/27/2022]
Abstract
Venomous animals have evolved toxins that interfere with specific components of their victim's core physiological systems, thereby causing biological dysfunction that aids in prey capture, defense against predators, or other roles such as intraspecific competition. Many animal lineages evolved venom systems independently, highlighting the success of this strategy. Over the course of evolution, toxins with exceptional specificity and high potency for their intended molecular targets have prevailed, making venoms an invaluable and almost inexhaustible source of bioactive molecules, some of which have found use as pharmacological tools, human therapeutics, and bioinsecticides. Current biomedically-focused research on venoms is directed towards their use in delineating the physiological role of toxin molecular targets such as ion channels and receptors, studying or treating human diseases, targeting vectors of human diseases, and treating microbial and parasitic infections. We provide examples of each of these areas of venom research, highlighting the potential that venom molecules hold for basic research and drug development.
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Affiliation(s)
- Volker Herzig
- School of Science & Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia; Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia.
| | | | - Mathilde R Israel
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | - Samantha A Nixon
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia.
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8
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Cristofori-Armstrong B, Saez NJ, Chassagnon IR, King GF, Rash LD. The modulation of acid-sensing ion channel 1 by PcTx1 is pH-, subtype- and species-dependent: Importance of interactions at the channel subunit interface and potential for engineering selective analogues. Biochem Pharmacol 2019; 163:381-390. [PMID: 30849303 DOI: 10.1016/j.bcp.2019.03.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/04/2019] [Indexed: 01/13/2023]
Abstract
Acid-sensing ion channels (ASICs) are primary acid sensors in the mammalian nervous system that are activated by protons under conditions of local acidosis. They have been implicated in a range of pathologies including ischemic stroke (ASIC1a subtype) and peripheral pain (ASIC1b and ASIC3). Although the spider venom peptide PcTx1 is the best-studied ASIC modulator and is neuroprotective in rodent models of ischemic stroke, little experimental work has been done to examine its molecular interaction with human ASIC1a or the off-target ASIC1b. The complementary face of the acidic pocket binding site of PcTx1 is where these channels differ in sequence. We show here that although PcTx1 is 10-fold less potent at human ASIC1a than the rat channel, the apparent affinity for the two channels is comparable. We examined the pharmacophore of PcTx1 for human ASIC1a and rat ASIC1b, and show that inhibitory and stimulatory effects at each ASIC1 variant is driven mostly by a shared set of core peptide pharmacophore residues that bind to the thumb domain, while peptide residues that interact with the complementary face of the biding site underlie species and subtype-dependent differences in activity that may allow manipulation of ASIC1 variant selectivity. Finally, the stimulatory effect of PcTx1 on rat ASIC1a when applied under mildly alkaline pH correlates with low receptor occupancy. These new insights into the interactions between PcTx1 with ASIC1 subtypes demonstrates the complexity of its mechanism of action, and highlights important implications to consider when using PcTx1 as a pharmacological tool to study ASIC function.
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Affiliation(s)
- Ben Cristofori-Armstrong
- School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Natalie J Saez
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Irène R Chassagnon
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Lachlan D Rash
- School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia.
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Saez NJ, Peppermint Lee JY, Cristofori-Armstrong B, Anangi R, King GF, Smith MT, Rash LD. Acid-sensing ion channel modulator, APETx2, has a more complex phamacological and therapeutic profile than previously reported. Toxicon 2019. [DOI: 10.1016/j.toxicon.2018.10.089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Silva A, Cristofori-Armstrong B, Rash LD, Hodgson WC, Isbister GK. Defining the role of post-synaptic α-neurotoxins in paralysis due to snake envenoming in humans. Cell Mol Life Sci 2018; 75:4465-4478. [PMID: 30069700 DOI: 10.1007/s00018-018-2893-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/21/2018] [Accepted: 07/26/2018] [Indexed: 01/06/2023]
Abstract
Snake venom α-neurotoxins potently inhibit rodent nicotinic acetylcholine receptors (nAChRs), but their activity on human receptors and their role in human paralysis from snakebite remain unclear. We demonstrate that two short-chain α-neurotoxins (SαNTx) functionally inhibit human muscle-type nAChR, but are markedly more reversible than against rat receptors. In contrast, two long-chain α-neurotoxins (LαNTx) show no species differences in potency or reversibility. Mutant studies identified two key residues accounting for this. Proteomic and clinical data suggest that paralysis in human snakebites is not associated with SαNTx, but with LαNTx, such as in cobras. Neuromuscular blockade produced by both subclasses of α-neurotoxins was reversed by antivenom in rat nerve-muscle preparations, supporting its effectiveness in human post-synaptic paralysis.
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Affiliation(s)
- Anjana Silva
- Monash Venom Group, Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, 50008, Sri Lanka
| | - Ben Cristofori-Armstrong
- School of Biomedical Sciences, University of Queensland, St. Lucia, QLD, 4072, Australia
- Institute of Molecular Bioscience, University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Lachlan D Rash
- School of Biomedical Sciences, University of Queensland, St. Lucia, QLD, 4072, Australia.
- Institute of Molecular Bioscience, University of Queensland, St. Lucia, QLD, 4072, Australia.
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
| | - Geoffrey K Isbister
- Monash Venom Group, Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
- Clinical Toxicology Research Group, University of Newcastle, Callaghan, NSW, 2308, Australia.
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11
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Madio B, Peigneur S, Chin YKY, Hamilton BR, Henriques ST, Smith JJ, Cristofori-Armstrong B, Dekan Z, Boughton BA, Alewood PF, Tytgat J, King GF, Undheim EAB. PHAB toxins: a unique family of predatory sea anemone toxins evolving via intra-gene concerted evolution defines a new peptide fold. Cell Mol Life Sci 2018; 75:4511-4524. [PMID: 30109357 DOI: 10.1007/s00018-018-2897-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/26/2018] [Accepted: 07/31/2018] [Indexed: 10/28/2022]
Abstract
Sea anemone venoms have long been recognized as a rich source of peptides with interesting pharmacological and structural properties, but they still contain many uncharacterized bioactive compounds. Here we report the discovery, three-dimensional structure, activity, tissue localization, and putative function of a novel sea anemone peptide toxin that constitutes a new, sixth type of voltage-gated potassium channel (KV) toxin from sea anemones. Comprised of just 17 residues, κ-actitoxin-Ate1a (Ate1a) is the shortest sea anemone toxin reported to date, and it adopts a novel three-dimensional structure that we have named the Proline-Hinged Asymmetric β-hairpin (PHAB) fold. Mass spectrometry imaging and bioassays suggest that Ate1a serves a primarily predatory function by immobilising prey, and we show this is achieved through inhibition of Shaker-type KV channels. Ate1a is encoded as a multi-domain precursor protein that yields multiple identical mature peptides, which likely evolved by multiple domain duplication events in an actinioidean ancestor. Despite this ancient evolutionary history, the PHAB-encoding gene family exhibits remarkable sequence conservation in the mature peptide domains. We demonstrate that this conservation is likely due to intra-gene concerted evolution, which has to our knowledge not previously been reported for toxin genes. We propose that the concerted evolution of toxin domains provides a hitherto unrecognised way to circumvent the effects of the costly evolutionary arms race considered to drive toxin gene evolution by ensuring efficient secretion of ecologically important predatory toxins.
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Affiliation(s)
- Bruno Madio
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven, Leuven, 3000, Belgium
| | - Yanni K Y Chin
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Brett R Hamilton
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Jennifer J Smith
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Ben Cristofori-Armstrong
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Zoltan Dekan
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Berin A Boughton
- Metabolomics Australia, School of Biosciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven, Leuven, 3000, Belgium
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.
| | - Eivind A B Undheim
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia.
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12
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Shen H, Li Z, Jiang Y, Pan X, Wu J, Cristofori-Armstrong B, Smith JJ, Chin YKY, Lei J, Zhou Q, King GF, Yan N. Structural basis for the modulation of voltage-gated sodium channels by animal toxins. Science 2018; 362:science.aau2596. [DOI: 10.1126/science.aau2596] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/17/2018] [Indexed: 12/31/2022]
Abstract
Animal toxins that modulate the activity of voltage-gated sodium (Nav) channels are broadly divided into two categories—pore blockers and gating modifiers. The pore blockers tetrodotoxin (TTX) and saxitoxin (STX) are responsible for puffer fish and shellfish poisoning in humans, respectively. Here, we present structures of the insect Navchannel NavPaS bound to a gating modifier toxin Dc1a at 2.8 angstrom-resolution and in the presence of TTX or STX at 2.6-Å and 3.2-Å resolution, respectively. Dc1a inserts into the cleft between VSDIIand the pore of NavPaS, making key contacts with both domains. The structures with bound TTX or STX reveal the molecular details for the specific blockade of Na+access to the selectivity filter from the extracellular side by these guanidinium toxins. The structures shed light on structure-based development of Navchannel drugs.
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13
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Pineda SS, Chaumeil PA, Kunert A, Kaas Q, Thang MWC, Le L, Nuhn M, Herzig V, Saez NJ, Cristofori-Armstrong B, Anangi R, Senff S, Gorse D, King GF. ArachnoServer 3.0: an online resource for automated discovery, analysis and annotation of spider toxins. Bioinformatics 2018; 34:1074-1076. [PMID: 29069336 DOI: 10.1093/bioinformatics/btx661] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 10/17/2017] [Indexed: 11/15/2022] Open
Abstract
Summary ArachnoServer is a manually curated database that consolidates information on the sequence, structure, function and pharmacology of spider-venom toxins. Although spider venoms are complex chemical arsenals, the primary constituents are small disulfide-bridged peptides that target neuronal ion channels and receptors. Due to their high potency and selectivity, these peptides have been developed as pharmacological tools, bioinsecticides and drug leads. A new version of ArachnoServer (v3.0) has been developed that includes a bioinformatics pipeline for automated detection and analysis of peptide toxin transcripts in assembled venom-gland transcriptomes. ArachnoServer v3.0 was updated with the latest sequence, structure and functional data, the search-by-mass feature has been enhanced, and toxin cards provide additional information about each mature toxin. Availability and implementation http://arachnoserver.org. Contact support@arachnoserver.org. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
| | | | - Anne Kunert
- Institute for Molecular Bioscience.,Queensland Facility for Advanced Bioinformatics
| | | | - Mike W C Thang
- Institute for Molecular Bioscience.,Queensland Facility for Advanced Bioinformatics
| | - Lien Le
- EMBL Australia Bioinformatics Resource (EMBL ABR), The University of Queensland, St Lucia, QLD 4072, Australia
| | - Michael Nuhn
- EMBL Australia Bioinformatics Resource (EMBL ABR), The University of Queensland, St Lucia, QLD 4072, Australia
| | | | | | | | | | | | - Dominique Gorse
- Institute for Molecular Bioscience.,Queensland Facility for Advanced Bioinformatics
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14
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Lee JYP, Saez NJ, Cristofori-Armstrong B, Anangi R, King GF, Smith MT, Rash LD. Inhibition of acid-sensing ion channels by diminazene and APETx2 evoke partial and highly variable antihyperalgesia in a rat model of inflammatory pain. Br J Pharmacol 2018; 175:2204-2218. [PMID: 29134638 DOI: 10.1111/bph.14089] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 10/22/2017] [Accepted: 10/31/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Acid-sensing ion channels (ASICs) are primary acid sensors in mammals, with the ASIC1b and ASIC3 subtypes being involved in peripheral nociception. The antiprotozoal drug diminazene is a moderately potent ASIC inhibitor, but its analgesic activity has not been assessed. EXPERIMENTAL APPROACH We determined the ASIC subtype selectivity of diminazene and the mechanism by which it inhibits ASICs using voltage-clamp electrophysiology of Xenopus oocytes expressing ASICs 1-3. Its peripheral analgesic activity was then assessed relative to APETx2, an ASIC3 inhibitor, and morphine, in a Freund's complete adjuvant (FCA)-induced rat model of inflammatory pain. KEY RESULTS Diminazene inhibited homomeric rat ASICs with IC50 values of ~200-800 nM, via an open channel and subtype-dependent mechanism. In rats with FCA-induced inflammatory pain in one hindpaw, diminazene and APETx2 evoked more potent peripheral antihyperalgesia than morphine, but the effect was partial for APETx2. APETx2 potentiated rat ASIC1b at concentrations 30-fold to 100-fold higher than the concentration inhibiting ASIC3, which may have implications for its use in in vivo experiments. CONCLUSIONS AND IMPLICATIONS Diminazene and APETx2 are moderately potent ASIC inhibitors, both inducing peripheral antihyperalgesia in a rat model of chronic inflammatory pain. APETx2 has a more complex ASIC pharmacology, which must be considered when it is used as a supposedly selective ASIC3 inhibitor in vivo. Our use of outbred rats revealed responders and non-responders when ASIC inhibition was used to alleviate inflammatory pain, which is aligned with the concept of number-needed-to-treat in human clinical studies. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.
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Affiliation(s)
- Jia Yu Peppermint Lee
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia
| | - Natalie J Saez
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | | | - Raveendra Anangi
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Maree T Smith
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia.,School of Pharmacy, The University of Queensland, St Lucia, QLD, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia.,School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
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15
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Wingerd JS, Mozar CA, Ussing CA, Murali SS, Chin YKY, Cristofori-Armstrong B, Durek T, Gilchrist J, Vaughan CW, Bosmans F, Adams DJ, Lewis RJ, Alewood PF, Mobli M, Christie MJ, Rash LD. The tarantula toxin β/δ-TRTX-Pre1a highlights the importance of the S1-S2 voltage-sensor region for sodium channel subtype selectivity. Sci Rep 2017; 7:974. [PMID: 28428547 PMCID: PMC5430537 DOI: 10.1038/s41598-017-01129-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/27/2017] [Indexed: 11/09/2022] Open
Abstract
Voltage-gated sodium (NaV) channels are essential for the transmission of pain signals in humans making them prime targets for the development of new analgesics. Spider venoms are a rich source of peptide modulators useful to study ion channel structure and function. Here we describe β/δ-TRTX-Pre1a, a 35-residue tarantula peptide that selectively interacts with neuronal NaV channels inhibiting peak current of hNaV1.1, rNaV1.2, hNaV1.6, and hNaV1.7 while concurrently inhibiting fast inactivation of hNaV1.1 and rNaV1.3. The DII and DIV S3-S4 loops of NaV channel voltage sensors are important for the interaction of Pre1a with NaV channels but cannot account for its unique subtype selectivity. Through analysis of the binding regions we ascertained that the variability of the S1-S2 loops between NaV channels contributes substantially to the selectivity profile observed for Pre1a, particularly with regards to fast inactivation. A serine residue on the DIV S2 helix was found to be sufficient to explain Pre1a’s potent and selective inhibitory effect on the fast inactivation process of NaV1.1 and 1.3. This work highlights that interactions with both S1-S2 and S3-S4 of NaV channels may be necessary for functional modulation, and that targeting the diverse S1-S2 region within voltage-sensing domains provides an avenue to develop subtype selective tools.
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Affiliation(s)
- Joshua S Wingerd
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Christine A Mozar
- Discipline of Pharmacology, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Christine A Ussing
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.,Novo Nordisk A/S, Copenhagen Area, Capital Region, Denmark
| | - Swetha S Murali
- Discipline of Pharmacology, University of Sydney, Camperdown, NSW, 2006, Australia.,Harvard Medical School, Children's Hospital, 300 Longwood Ave, Boston, MA, 02115, United States
| | - Yanni K-Y Chin
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Ben Cristofori-Armstrong
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Thomas Durek
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - John Gilchrist
- Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Christopher W Vaughan
- Pain Management Research Institute, University of Sydney, St Leonards, NSW, 2006, Australia
| | - Frank Bosmans
- Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - David J Adams
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Mehdi Mobli
- Centre for Advanced Imaging & School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Macdonald J Christie
- Discipline of Pharmacology, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia. .,School of Biomedical Sciences, The University of Queensland, St Lucia, 4072, QLD, Australia.
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16
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Er SY, Cristofori-Armstrong B, Escoubas P, Rash LD. Discovery and molecular interaction studies of a highly stable, tarantula peptide modulator of acid-sensing ion channel 1. Neuropharmacology 2017; 127:185-195. [PMID: 28327374 DOI: 10.1016/j.neuropharm.2017.03.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/05/2017] [Accepted: 03/17/2017] [Indexed: 12/17/2022]
Abstract
Acute pharmacological inhibition of acid-sensing ion channel 1a (ASIC1a) is efficacious in rodent models in alleviating symptoms of neurological diseases such as stroke and multiple sclerosis. Thus, ASIC1a is a promising therapeutic target and selective ligands that modulate it are invaluable research tools and potential therapeutic leads. Spider venoms have provided an abundance of voltage-gated ion channel modulators, however, only one ASIC modulator (PcTx1) has so far been isolated from this source. Here we report the discovery, characterization, and chemical stability of a second spider venom peptide that potently modulates ASIC1a and ASIC1b, and investigate the molecular basis for its subtype selectivity. π-TRTX-Hm3a (Hm3a) is a 37-amino acid peptide isolated from Togo starburst tarantula (Heteroscodra maculata) venom with five amino acid substitutions compared to PcTx1, and is also three residues shorter at the C-terminus. Hm3a pH-dependently inhibited ASIC1a with an IC50 of 1-2 nM and potentiated ASIC1b with an EC50 of 46.5 nM, similar to PcTx1. Using ASIC1a to ASIC1b point mutants in rat ASIC1a revealed that Glu177 and Arg175 in the palm region opposite α-helix 5 play an important role in the Hm3a-ASIC1 interaction and contribute to the subtype-dependent effects of the peptide. Despite its high sequence similarity with PcTx1, Hm3a showed higher levels of stability over 48 h. Overall, Hm3a represents a potent, highly stable tool for the study of ASICs and will be particularly useful when stability in biological fluids is required, for example in long term in vitro cell-based assays and in vivo experiments. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Sing Yan Er
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | | | - Pierre Escoubas
- VenomeTech, 473 Route des Dolines, Villa 3, 06560 Valbonne, France
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia; School of Biomedical Sciences, The University of Queensland, St Lucia, QLD 4072, Australia.
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17
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Abstract
Recombinant expression of disulfide-reticulated peptides and proteins is often challenging. We describe a method that exploits the periplasmic disulfide-bond forming machinery of Escherichia coli and combines this with a cleavable, solubility-enhancing fusion tag to obtain higher yields of correctly folded target protein than is achievable via cytoplasmic expression. The protocols provided herein cover all aspects of this approach, from vector construction and transformation to purification of the cleaved target protein and subsequent quality control.
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Affiliation(s)
- Natalie J Saez
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, St. Lucia, QLD, 4067, Australia.
| | - Ben Cristofori-Armstrong
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, St. Lucia, QLD, 4067, Australia
| | - Raveendra Anangi
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, St. Lucia, QLD, 4067, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, St. Lucia, QLD, 4067, Australia.
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18
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Cristofori-Armstrong B, Soh MS, Talwar S, Brown DL, Griffin JDO, Dekan Z, Stow JL, King GF, Lynch JW, Rash LD. Xenopus borealis as an alternative source of oocytes for biophysical and pharmacological studies of neuronal ion channels. Sci Rep 2015; 5:14763. [PMID: 26440210 PMCID: PMC4594035 DOI: 10.1038/srep14763] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/07/2015] [Indexed: 01/10/2023] Open
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 voltage- and 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.
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Affiliation(s)
| | - Ming S Soh
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Sahil Talwar
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Darren L Brown
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - John D O Griffin
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zoltan Dekan
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Joseph W Lynch
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia.,School of Biomedical Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
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19
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Saez NJ, Deplazes E, Cristofori-Armstrong B, Chassagnon IR, Lin X, Mobli M, Mark AE, Rash LD, King GF. Molecular dynamics and functional studies define a hot spot of crystal contacts essential for PcTx1 inhibition of acid-sensing ion channel 1a. Br J Pharmacol 2015; 172:4985-95. [PMID: 26248594 DOI: 10.1111/bph.13267] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 06/29/2015] [Accepted: 07/13/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE The spider-venom peptide PcTx1 is the most potent and selective inhibitor of acid-sensing ion channel (ASIC) 1a. It has centrally acting analgesic activity and is neuroprotective in rodent models of ischaemic stroke. Understanding the molecular details of the PcTx1 : ASIC1a interaction should facilitate development of therapeutically useful ASIC1a modulators. Previously, we showed that several key pharmacophore residues of PcTx1 reside in a dynamic β-hairpin loop; conclusions confirmed by recent crystal structures of the complex formed between PcTx1 and chicken ASIC1 (cASIC1). Numerous peptide : channel contacts were observed in these crystal structures, but it remains unclear which of these are functionally important. EXPERIMENTAL APPROACH We combined molecular dynamics (MD) simulations of the PcTx1 : cASIC1 complex with mutagenesis of PcTx1 and rat ASIC1a. KEY RESULTS Crystal structures of the PcTx1 : cASIC1 complex indicated that 15 PcTx1 residues form a total of 57 pairwise intermolecular contacts (<5 Å) with 32 channel residues. MD simulations, however, suggested that about half of these interactions do not persist in solution. Mutation to alanine of only eight of 15 PcTx1 contact residues substantially altered ASIC1a inhibition by PcTx1. Our data reveal that many of the peptide-channel interactions observed in the PcTx1 : cASIC1 crystal structures are not important for PcTx1 inhibition of rat ASIC1a. CONCLUSIONS AND IMPLICATIONS We identified the atomic interactions that are critical for PcTx1 inhibition of ASIC1a. Our data highlight the value of combining structural information, MD and functional experiments to obtain detailed insight into the molecular basis of protein : protein interactions.
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Affiliation(s)
- Natalie J Saez
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Evelyne Deplazes
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Ben Cristofori-Armstrong
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Irène R Chassagnon
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | | | - Mehdi Mobli
- Centre for Advanced Imaging, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Alan E Mark
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
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20
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Simons C, Rash LD, Crawford J, Ma L, Cristofori-Armstrong B, Miller D, Ru K, Baillie GJ, Alanay Y, Jacquinet A, Debray FG, Verloes A, Shen J, Yesil G, Guler S, Yuksel A, Cleary JG, Grimmond SM, McGaughran J, King GF, Gabbett MT, Taft RJ. Erratum: Corrigendum: Mutations in the voltage-gated potassium channel gene KCNH1 cause Temple-Baraitser syndrome and epilepsy. Nat Genet 2015; 47:304. [DOI: 10.1038/ng0315-304b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Simons C, Rash LD, Crawford J, Ma L, Cristofori-Armstrong B, Miller D, Ru K, Baillie GJ, Alanay Y, Jacquinet A, Debray FG, Verloes A, Shen J, Yesil G, Guler S, Yuksel A, Cleary JG, Grimmond SM, McGaughran J, King GF, Gabbett MT, Taft RJ. Mutations in the voltage-gated potassium channel gene KCNH1 cause Temple-Baraitser syndrome and epilepsy. Nat Genet 2014; 47:73-7. [PMID: 25420144 DOI: 10.1038/ng.3153] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 10/31/2014] [Indexed: 12/15/2022]
Abstract
Temple-Baraitser syndrome (TBS) is a multisystem developmental disorder characterized by intellectual disability, epilepsy, and hypoplasia or aplasia of the nails of the thumb and great toe. Here we report damaging de novo mutations in KCNH1 (encoding a protein called ether à go-go, EAG1 or KV10.1), a voltage-gated potassium channel that is predominantly expressed in the central nervous system (CNS), in six individuals with TBS. Characterization of the mutant channels in both Xenopus laevis oocytes and human HEK293T cells showed a decreased threshold of activation and delayed deactivation, demonstrating that TBS-associated KCNH1 mutations lead to deleterious gain of function. Consistent with this result, we find that two mothers of children with TBS, who have epilepsy but are otherwise healthy, are low-level (10% and 27%) mosaic carriers of pathogenic KCNH1 mutations. Consistent with recent reports, this finding demonstrates that the etiology of many unresolved CNS disorders, including epilepsies, might be explained by pathogenic mosaic mutations.
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Affiliation(s)
- Cas Simons
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Joanna Crawford
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Linlin Ma
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ben Cristofori-Armstrong
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - David Miller
- 1] Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia. [2] Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Kelin Ru
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Gregory J Baillie
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Yasemin Alanay
- Pediatric Genetics, Department of Pediatrics, Acibadem University School of Medicine, Istanbul, Turkey
| | - Adeline Jacquinet
- Center for Human Genetics, Centre Hospitalier Universitaire and University of Liège, Liège, Belgium
| | | | - Alain Verloes
- 1] Department of Genetics, Assistance Publique des Hôpitaux de Paris (AP-HP), Robert Debré Hospital, Paris, France. [2] INSERM UMR 1141, Robert Debré Hospital, Paris, France
| | - Joseph Shen
- Medical Genetics and Metabolism, Children's Hospital Central California, Madera, California, USA
| | - Gözde Yesil
- Department of Medical Genetics, Bezmialem Vakif University School of Medicine, Istanbul, Turkey
| | - Serhat Guler
- Department of Medical Genetics, Bezmialem Vakif University School of Medicine, Istanbul, Turkey
| | - Adnan Yuksel
- Department of Medical Genetics, Bezmialem Vakif University School of Medicine, Istanbul, Turkey
| | | | - Sean M Grimmond
- 1] Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia. [2] Wolfson Wohl Cancer Research Centre, Institute for Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Julie McGaughran
- 1] Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia. [2] School of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Michael T Gabbett
- 1] Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia. [2] School of Medicine, Griffith University, Gold Coast, Queensland, Australia
| | - Ryan J Taft
- 1] Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia. [2] Department of Integrated Systems Biology, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA. [3] Department of Pediatrics, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA. [4] Illumina, Inc., San Diego, California, USA
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Jensen JE, Cristofori-Armstrong B, Anangi R, Rosengren KJ, Lau CHY, Mobli M, Brust A, Alewood PF, King GF, Rash LD. Understanding the molecular basis of toxin promiscuity: the analgesic sea anemone peptide APETx2 interacts with acid-sensing ion channel 3 and hERG channels via overlapping pharmacophores. J Med Chem 2014; 57:9195-203. [PMID: 25337890 DOI: 10.1021/jm501400p] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The sea anemone peptide APETx2 is a potent and selective blocker of acid-sensing ion channel 3 (ASIC3). APETx2 is analgesic in a variety of rodent pain models, but the lack of knowledge of its pharmacophore and binding site on ASIC3 has impeded development of improved analogues. Here we present a detailed structure-activity relationship study of APETx2. Determination of a high-resolution structure of APETx2 combined with scanning mutagenesis revealed a cluster of aromatic and basic residues that mediate its interaction with ASIC3. We show that APETx2 also inhibits the off-target hERG channel by reducing the maximal current amplitude and shifting the voltage dependence of activation to more positive potentials. Electrophysiological screening of selected APETx2 mutants revealed partial overlap between the surfaces on APETx2 that mediate its interaction with ASIC3 and hERG. Characterization of the molecular basis of these interactions is an important first step toward the rational design of more selective APETx2 analogues.
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Affiliation(s)
- Jonas E Jensen
- Institute for Molecular Bioscience, ‡School of Biomedical Sciences, and §Centre for Advanced Imaging, The University of Queensland , St Lucia, QLD 4072, Australia
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