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Xian T, Cao M, Chen K, Zhao W, Liu Y, Yao W, Guang H, Yang Y, Su M, Zhang R, Ma J, Ma L, Gao J. Identification of a novel protein Hq023 of the hard tick Haemaphysalis qinghaiensis and preliminary evaluation of its analgesic effect in mice model. Parasitol Int 2024; 103:102933. [PMID: 39048024 DOI: 10.1016/j.parint.2024.102933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 07/19/2024] [Accepted: 07/20/2024] [Indexed: 07/27/2024]
Abstract
Tick saliva contains a range of critical biological molecules which could inhibit host defenses and guarantee their food supply. Hq023, a novel cDNA sequence, was cloned from a cDNA library constructed from salivary glands of partially-engorged Haemaphysalis qinghaiensis. Hq023 has an open reading frame (ORF) of 408 bp coding a protein containing 135 amino acid residues with a molecular mass of 15 kDa. Database homology showed that Hq023 protein was structurally similar to a natural toxin U33-theraphotoxin-Cg1c from the Chinese tarantula Chilobrachys guangxiensis. A recombinant protein was expressed with the novel cDNA in a prokaryotic system and its analgesic effect was evaluated in mice model. Both tail immersion and hot-plate tests uncovered an antinociceptive activity, while in the acetic acid-induced writhing test this effect was not observed. These results indicated that the novel recombinant protein Hq023 (rHq023) probably possessed a central antinociceptive activity. Finding of the novel protein might pave a new avenue for the development of tick-derived analgesics.
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Affiliation(s)
- Tong Xian
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China; Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou 014000, China
| | - Meina Cao
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China
| | - Kaiting Chen
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China
| | - Wenbin Zhao
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China
| | - Yueqing Liu
- Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou 014000, China
| | - Wenjing Yao
- Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou 014000, China
| | - Hui Guang
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China
| | - Yinran Yang
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China
| | - Muya Su
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China
| | - Ruijuan Zhang
- Department of Pharmacy, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China
| | - Jing Ma
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China; Third Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou 450003, China
| | - Linyuan Ma
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China; Ordos Clinical Medical College, Inner Mongolia Medical University, Ordos 017000, China
| | - Jinliang Gao
- Laboratory of Molecular Medicine, Ordos Central Hospital, Inner Mongolia Autonomous Region, Ordos 017000, China; Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou 014000, China; Ordos Clinical Medical College, Inner Mongolia Medical University, Ordos 017000, China.
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Liu XY, Huang JC, Zhang T, Wang HR, Xu QH, Xia YG, Xu AJ, Yang ZY, Sun L, Zhao WJ, Zhao J, Qian F, Hou AJ. Cyclo(L-Pro-L-Trp) from Chilobrachys jingzhao alleviates formalin-induced inflammatory pain by suppressing the inflammatory response and inhibiting TRAF6-mediated MAPK and NF-κB signaling pathways. Int Immunopharmacol 2024; 139:112602. [PMID: 39033660 DOI: 10.1016/j.intimp.2024.112602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/26/2024] [Accepted: 06/28/2024] [Indexed: 07/23/2024]
Abstract
Chronic pain has emerged as a significant public health issue, seriously affecting patients' quality of life and psychological well-being, with a lack of effective pharmacological treatments. Numerous studies have indicated that macrophages play a crucial role in inflammatory pain, and targeting neuro-immune interactions for drug development may represent a promising direction for pain management. Chilobrachys jingzhao (C. jingzhao) is used as a folk medicine of the Li nationality with the efficacy of eliminating swelling, detoxicating, and relieving pain, and the related products are widely used in the market. However, the chemical constituents of C. jingzhao have not been reported, and the pharmacodynamic substance and the precise functional mechanism are unrevealed. Here we isolated a cyclic dipeptide, cyclo(L-Pro-L-Trp) (CPT) from C. jingzhao for the first time. CPT remarkably alleviated formalin-induced inflammatory pain and significantly inhibited inflammatory responses. In vivo, CPT attenuated neutrophil infiltration and plantar tissue edema and suppressed the mRNA expression of pro-inflammatory molecules. In vitro, CPT suppressed inflammation triggered by lipopolysaccharide (LPS) in both RAW 264.7 and iBMDM cells, reducing expressions of inducible nitric oxide synthase (iNOS), superoxide, and pro-inflammatory molecules. A mechanistic study revealed that CPT exerted an anti-inflammatory activity by blocking the mitogen-activated protein kinases (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways, as well as alleviating the ubiquitination of tumor necrosis factor receptor-associated factor 6 (TRAF6). Our results elucidated the pharmacodynamic material basis of C. jingzhao, and CPT can be a promising lead for alleviating inflammation and inflammatory pain.
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Affiliation(s)
- Xin-Yue Liu
- Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; National Key Laboratory of Innovative Immunotherapy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jin-Chang Huang
- Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; National Key Laboratory of Innovative Immunotherapy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tao Zhang
- Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, 358 Datong Road, Pudong New District, Shanghai 200137, China
| | - Han-Rui Wang
- Hainan Spider King Biotechnology Co., Ltd., Haikou 570125, China
| | - Qi-Hui Xu
- Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; National Key Laboratory of Innovative Immunotherapy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yu-Gui Xia
- Institute of Artificial Intelligence Biomedicine, Nanjing University, Nanjing 210008, China
| | - A-Jing Xu
- Department of Clinical Pharmacy, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Ze-Yong Yang
- Department of Anesthesiology, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Lei Sun
- Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; National Key Laboratory of Innovative Immunotherapy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wen-Juan Zhao
- Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; National Key Laboratory of Innovative Immunotherapy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jun Zhao
- Hainan Spider King Biotechnology Co., Ltd., Haikou 570125, China.
| | - Feng Qian
- Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; National Key Laboratory of Innovative Immunotherapy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Ai-Jun Hou
- Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; National Key Laboratory of Innovative Immunotherapy, Shanghai Jiao Tong University, Shanghai 200240, China.
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A Pseudoscorpion's Promising Pinch: The venom of Chelifer cancroides contains a rich source of novel compounds. Toxicon 2021; 201:92-104. [PMID: 34416254 DOI: 10.1016/j.toxicon.2021.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 12/12/2022]
Abstract
With pedipalps modified for venom injection, some pseudoscorpions possess a unique venom delivery system, which evolved independently from those of other arachnids like scorpions and spiders. Up to now, only a few studies have been focused on pseudoscorpion venom, which either identified a small fraction of venom compounds, or were based on solely transcriptomic approaches. Only one study addressed the bioactivity of pseudoscorpion venom. Here, we expand existing knowledge about pseudoscorpion venom by providing a comprehensive proteomic and transcriptomic analysis of the venom of Chelifer cancroides. We identified the first putative genuine toxins in the venom of C. cancroides and we showed that a large fraction of the venom comprises novel compounds. In addition, we tested the activity of the venom at specific ion channels for the first time. These tests demonstrate that the venom of C. cancroides causes inhibition of a voltage-gated insect potassium channel (Shaker IR) and modulates the inactivation process of voltage-gated sodium channels from Varroa destructor. For one of the smallest venomous animals ever studied, today's toolkits enabled a comprehensive venom analysis. This is demonstrated by allocating our identified venom compounds to more than half of the prominent ion signals in MALDI-TOF mass spectra of venom samples. The present study is a starting point for understanding the complex composition and activity of pseudoscorpion venom and provides a potential rich source of bioactive compounds useable for basic research and industrial application.
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Giribaldi J, Smith JJ, Schroeder CI. Recent developments in animal venom peptide nanotherapeutics with improved selectivity for cancer cells. Biotechnol Adv 2021; 50:107769. [PMID: 33989705 DOI: 10.1016/j.biotechadv.2021.107769] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/06/2021] [Accepted: 05/08/2021] [Indexed: 02/07/2023]
Abstract
Animal venoms are a rich source of bioactive peptides that efficiently modulate key receptors and ion channels involved in cellular excitability to rapidly neutralize their prey or predators. As such, they have been a wellspring of highly useful pharmacological tools for decades. Besides targeting ion channels, some venom peptides exhibit strong cytotoxic activity and preferentially affect cancer over healthy cells. This is unlikely to be driven by an evolutionary impetus, and differences in tumor cells and the tumor microenvironment are probably behind the serendipitous selectivity shown by some venom peptides. However, strategies such as bioconjugation and nanotechnologies are showing potential to improve their selectivity and potency, thereby paving the way to efficiently harness new anticancer mechanisms offered by venom peptides. This review aims to highlight advances in nano- and chemotherapeutic tools and prospective anti-cancer drug leads derived from animal venom peptides.
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Affiliation(s)
- Julien Giribaldi
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Jennifer J Smith
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Christina I Schroeder
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
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Guo X, Li B, Liang S, Lai R, Liu H. A novel Kunitz-type neurotoxin peptide identified from skin secretions of the frog Amolops loloensis. Biochem Biophys Res Commun 2020; 528:99-104. [DOI: 10.1016/j.bbrc.2020.05.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 05/09/2020] [Indexed: 01/11/2023]
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Deng M, Jiang L, Luo X, Tao H, Liang S. Jingzhaotoxin-X, a gating modifier of Kv4.2 and Kv4.3 potassium channels purified from the venom of the Chinese tarantula Chilobrachys jingzhao. J Venom Anim Toxins Incl Trop Dis 2020; 26:e20190043. [PMID: 32536941 PMCID: PMC7269146 DOI: 10.1590/1678-9199-jvatitd-2019-0043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background The tarantula Chilobrachys jingzhao is one of the largest venomous spiders in China. In previous studies, we purified and characterized at least eight peptides from C. jingzhao venom. In this report, we describe the purification and characterization of Jingzhaotoxin-X (JZTX-X), which selectively blocks Kv4.2 and Kv4.3 potassium channels. Methods JZTX-X was purified using a combination of cation-exchange HPLC and reverse-phase HPLC. The amino-acid sequence was determined by automated Edman degradation and confirmed by mass spectrometry (MS). Voltage-gated ion channel currents were recorded in HEK293t cells transiently transfected with a variety of ion channel constructs. In addition, the hyperalgesic activity of JZTX-X and the toxin´s effect on motor function were assessed in mice. Results JZTX-X contained 31 amino acids, with six cysteine residues that formed three disulfide bonds within an inhibitory cysteine knot (ICK) topology. In whole-cell voltage-clamp experiments, JZTX-X inhibited Kv4.2 and Kv4.3 potassium channels in a concentration- and voltage-dependent manner, without affecting other ion channels (Kv1.1, 1.2, 1.3, 2.1, delayed rectifier potassium channels, high- and low-voltage-activated Ca2+ channels, and voltage-gated sodium channels Nav1.5 and 1.7). JZTX-X also shifted the voltage-dependent channel activation to more depolarized potentials, whereas extreme depolarization caused reversible toxin binding to Kv4.2 channels. JZTX-X shifted the Kv4.2 and Kv4.3 activities towards a resting state, since at the resting potential the toxin completely inhibited the channels, even in the absence of an applied physical stimulus. Intrathecal or intraplantar injection of JZTX-X caused a long-lasting decrease in the mechanical nociceptive threshold (hyperalgesia) but had no effect on motor function as assessed in the rotarod test. Conclusions JZTX-X selectively suppresses Kv4.2 and Kv4.3 potassium channel activity in a concentration- and voltage-dependent manner and causes long-lasting mechanical hyperalgesia.
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Affiliation(s)
- Meichun Deng
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Central South University, Changsha, Hunan 410013, China
| | - Liping Jiang
- Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha 410013, China
| | - Xuan Luo
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, 410081, China
| | - Huai Tao
- Department of Biochemistry and Molecular Biology, Hunan University of Chinese Medicine, Changsha 410208, Hunan, China
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, 410081, China
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Deng M, Jiang L, Luo X, Tao H, Liang S. Jingzhaotoxin-X, a gating modifier of Kv4.2 and Kv4.3 potassium channels purified from the venom of the Chinese tarantula Chilobrachys jingzhao. J Venom Anim Toxins Incl Trop Dis 2020. [DOI: 10.1590//1678-9199-jvatitd-2019-0043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
| | | | | | - Huai Tao
- Hunan University of Chinese Medicine, China
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8
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Spider Knottin Pharmacology at Voltage-Gated Sodium Channels and Their Potential to Modulate Pain Pathways. Toxins (Basel) 2019; 11:toxins11110626. [PMID: 31671792 PMCID: PMC6891507 DOI: 10.3390/toxins11110626] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/24/2019] [Accepted: 10/24/2019] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels (NaVs) are a key determinant of neuronal signalling. Neurotoxins from diverse taxa that selectively activate or inhibit NaV channels have helped unravel the role of NaV channels in diseases, including chronic pain. Spider venoms contain the most diverse array of inhibitor cystine knot (ICK) toxins (knottins). This review provides an overview on how spider knottins modulate NaV channels and describes the structural features and molecular determinants that influence their affinity and subtype selectivity. Genetic and functional evidence support a major involvement of NaV subtypes in various chronic pain conditions. The exquisite inhibitory properties of spider knottins over key NaV subtypes make them the best lead molecules for the development of novel analgesics to treat chronic pain.
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Cardoso FC, Lewis RJ. Structure-Function and Therapeutic Potential of Spider Venom-Derived Cysteine Knot Peptides Targeting Sodium Channels. Front Pharmacol 2019; 10:366. [PMID: 31031623 PMCID: PMC6470632 DOI: 10.3389/fphar.2019.00366] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 03/25/2019] [Indexed: 12/11/2022] Open
Abstract
Spider venom-derived cysteine knot peptides are a mega-diverse class of molecules that exhibit unique pharmacological properties to modulate key membrane protein targets. Voltage-gated sodium channels (NaV) are often targeted by these peptides to allosterically promote opening or closing of the channel by binding to structural domains outside the channel pore. These effects can result in modified pain responses, muscle paralysis, cardiac arrest, priapism, and numbness. Although such effects are often deleterious, subtype selective spider venom peptides are showing potential to treat a range of neurological disorders, including chronic pain and epilepsy. This review examines the structure–activity relationships of cysteine knot peptides from spider venoms that modulate NaV and discusses their potential as leads to novel therapies for neurological disorders.
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Affiliation(s)
- Fernanda C Cardoso
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Richard J Lewis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
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Meredith FL, Rennie KJ. Regional and Developmental Differences in Na + Currents in Vestibular Primary Afferent Neurons. Front Cell Neurosci 2018; 12:423. [PMID: 30487736 PMCID: PMC6246661 DOI: 10.3389/fncel.2018.00423] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/29/2018] [Indexed: 02/04/2023] Open
Abstract
The vestibular system relays information about head position via afferent nerve fibers to the brain in the form of action potentials. Voltage-gated Na+ channels in vestibular afferents drive the initiation and propagation of action potentials, but their expression during postnatal development and their contributions to firing in diverse mature afferent populations are unknown. Electrophysiological techniques were used to determine Na+ channel subunit types in vestibular calyx-bearing afferents at different stages of postnatal development. We used whole cell patch clamp recordings in thin slices of gerbil crista neuroepithelium to investigate Na+ channels and firing patterns in central zone (CZ) and peripheral zone (PZ) afferents. PZ afferents are exclusively dimorphic, innervating type I and type II hair cells, whereas CZ afferents can form dimorphs or calyx-only terminals which innervate type I hair cells alone. All afferents expressed tetrodotoxin (TTX)-sensitive Na+ currents, but TTX-sensitivity varied with age. During the fourth postnatal week, 200–300 nM TTX completely blocked sodium currents in PZ and CZ calyces. By contrast, in immature calyces [postnatal day (P) 5–11], a small component of peak sodium current remained in 200 nM TTX. Application of 1 μM TTX, or Jingzhaotoxin-III plus 200 nM TTX, abolished sodium current in immature calyces, suggesting the transient expression of voltage-gated sodium channel 1.5 (Nav1.5) during development. A similar TTX-insensitive current was found in early postnatal crista hair cells (P5–9) and constituted approximately one third of the total sodium current. The Nav1.6 channel blocker, 4,9-anhydrotetrodotoxin, reduced a component of sodium current in immature and mature calyces. At 100 nM 4,9-anhydrotetrodotoxin, peak sodium current was reduced on average by 20% in P5–14 calyces, by 37% in mature dimorphic PZ calyces, but by less than 15% in mature CZ calyx-only terminals. In mature PZ calyces, action potentials became shorter and broader in the presence of 4,9-anhydrotetrodotoxin implicating a role for Nav1.6 channels in firing in dimorphic afferents.
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Affiliation(s)
- Frances L Meredith
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Katherine J Rennie
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO, United States.,Department of Physiology & Biophysics, University of Colorado School of Medicine, Aurora, CO, United States
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Pharmacological analysis of Poecilotheria spider venoms in mice provides clues for human treatment. Toxicon 2017; 138:59-67. [DOI: 10.1016/j.toxicon.2017.08.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 11/20/2022]
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Wu L, Xie SS, Meng E, Li WY, Liu L, Zhang DY. Molecular Dynamics Simulation Reveals Unique Interplays Between a Tarantula Toxin and Lipid Membranes. J Membr Biol 2017; 250:315-325. [DOI: 10.1007/s00232-017-9965-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 06/01/2017] [Indexed: 01/18/2023]
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Yao M, Wang J, Wu L, Min L, Li WY, Zhu LY, Meng E, Zhang DY. An efficient strategy for the expression of Jingzhaotoxin-III in Escherichia coli. BIOTECHNOL BIOTEC EQ 2017. [DOI: 10.1080/13102818.2017.1304182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Hernández-Ochoa EO, Banks Q, Schneider MF. Acute Elevated Glucose Promotes Abnormal Action Potential-Induced Ca 2+ Transients in Cultured Skeletal Muscle Fibers. J Diabetes Res 2017; 2017:1509048. [PMID: 28835899 PMCID: PMC5557004 DOI: 10.1155/2017/1509048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/13/2022] Open
Abstract
A common comorbidity of diabetes is skeletal muscle dysfunction, which leads to compromised physical function. Previous studies of diabetes in skeletal muscle have shown alterations in excitation-contraction coupling (ECC)-the sequential link between action potentials (AP), intracellular Ca2+ release, and the contractile machinery. Yet, little is known about the impact of acute elevated glucose on the temporal properties of AP-induced Ca2+ transients and ionic underlying mechanisms that lead to muscle dysfunction. Here, we used high-speed confocal Ca2+ imaging to investigate the temporal properties of AP-induced Ca2+ transients, an intermediate step of ECC, using an acute in cellulo model of uncontrolled hyperglycemia (25 mM, 48 h.). Control and elevated glucose-exposed muscle fibers cultured for five days displayed four distinct patterns of AP-induced Ca2+ transients (phasic, biphasic, phasic-delayed, and phasic-slow decay); most control muscle fibers show phasic AP-induced Ca2+ transients, while most fibers exposed to elevated D-glucose displayed biphasic Ca2+ transients upon single field stimulation. We hypothesize that these changes in the temporal profile of the AP-induced Ca2+ transients are due to changes in the intrinsic excitable properties of the muscle fibers. We propose that these changes accompany early stages of diabetic myopathy.
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Affiliation(s)
- Erick O. Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- *Erick O. Hernández-Ochoa:
| | - Quinton Banks
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Martin F. Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Xu X, Zhang B, Yang S, An S, Ribeiro JMC, Andersen JF. Structure and Function of FS50, a salivary protein from the flea Xenopsylla cheopis that blocks the sodium channel Na V1.5. Sci Rep 2016; 6:36574. [PMID: 27819327 PMCID: PMC5098211 DOI: 10.1038/srep36574] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 10/14/2016] [Indexed: 11/10/2022] Open
Abstract
Naturally occurring toxins have been invaluable tools for the study of structural and functional relationships of voltage-gated sodium channels (VGSC). Few studies have been made of potential channel-modulating substances from blood-feeding arthropods. He we describe the characterization FS50, a salivary protein from the flea, Xenopsylla cheopis, that exhibits an inhibitory activity against the NaV1.5 channel with an IC50 of 1.58 μM. The pore-blocking mechanism of this toxin is evident from the kinetics of activation and inactivation suggesting that FS50 does not interfere with the voltage sensor of NaV1.5. FS50 exhibits high specificity for NaV1.5, since 10 μM FS50 had no discernable effect on voltage-gated Na+, K+ and Ca2+ channels in rat dorsal root ganglia or VGSC forms individually expressed in HEK 293T cells. Furthermore, intravenous injection of FS50 into rats and monkeys elicited recovery from arrhythmia induced by BaCl2, as would be expected from a blockade of NaV1.5. The crystal structure of FS50 revealed a βαββ domain similar to that of scorpion β toxin and a small N-terminal βαβ domain. Site-directed mutagenesis experiments have implicated a basic surface including the side chains of Arg 6, His 11 and Lys 32 as potentially important in the FS50 NaV1.5 interaction.
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Affiliation(s)
- Xueqing Xu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China.,The Laboratory of Malaria and Vector Research, NIAID, National Institutes of Health, Rockville, Maryland 20852 USA
| | - Bei Zhang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Shilong Yang
- The Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
| | - Su An
- The Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
| | - José M C Ribeiro
- The Laboratory of Malaria and Vector Research, NIAID, National Institutes of Health, Rockville, Maryland 20852 USA
| | - John F Andersen
- The Laboratory of Malaria and Vector Research, NIAID, National Institutes of Health, Rockville, Maryland 20852 USA
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YAO HM, WANG G, LIU YP, RONG MQ, SHEN CB, YAN XW, LUO XD, LAI R. Phenolic acids isolated from the fungus Schizophyllum commune exert analgesic activity by inhibiting voltage-gated sodium channels. Chin J Nat Med 2016; 14:661-670. [DOI: 10.1016/s1875-5364(16)30078-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Indexed: 02/06/2023]
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17
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Rong M, Liu J, Zhang M, Wang G, Zhao G, Wang G, Zhang Y, Hu K, Lai R. A sodium channel inhibitor ISTX-I with a novel structure provides a new hint at the evolutionary link between two toxin folds. Sci Rep 2016; 6:29691. [PMID: 27407029 PMCID: PMC4942781 DOI: 10.1038/srep29691] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/23/2016] [Indexed: 12/15/2022] Open
Abstract
Members of arachnida, such as spiders and scorpions, commonly produce venom with specialized venom glands, paralyzing their prey with neurotoxins that specifically target ion channels. Two well-studied motifs, the disulfide-directed hairpin (DDH) and the inhibitor cystine knot motif (ICK), are both found in scorpion and spider toxins. As arachnids, ticks inject a neurotoxin-containing cocktail from their salivary glands into the host to acquire a blood meal, but peptide toxins acting on ion channels have not been observed in ticks. Here, a new neurotoxin (ISTX-I) that acts on sodium channels was identified from the hard tick Ixodes scapularis and characterized. ISTX-I exhibits a potent inhibitory function with an IC50 of 1.6 μM for sodium channel Nav1.7 but not other sodium channel subtypes. ISTX-I adopts a novel structural fold and is distinct from the canonical ICK motif. Analysis of the ISTX-I, DDH and ICK motifs reveals that the new ISTX-I motif might be an intermediate scaffold between DDH and ICK, and ISTX-I is a clue to the evolutionary link between the DDH and ICK motifs. These results provide a glimpse into the convergent evolution of neurotoxins from predatory and blood-sucking arthropods.
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Affiliation(s)
- Mingqiang Rong
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences &Yunnan Province, Kunming Institute of Zoology, Kunming Yunnan 650223, China
| | - Jiangxin Liu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Meilin Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences &Yunnan Province, Kunming Institute of Zoology, Kunming Yunnan 650223, China
| | - Gan Wang
- Life Sciences College of Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Gang Zhao
- Yunnan Academy of Grassland and Animal Science, Xiaoshao, Kunming 650212, China
| | - Guodong Wang
- State Key Laboratory of Genetic Resources and Evolution, and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Yaping Zhang
- State Key Laboratory of Genetic Resources and Evolution, and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Kaifeng Hu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Ren Lai
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences &Yunnan Province, Kunming Institute of Zoology, Kunming Yunnan 650223, China.,Life Sciences College of Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
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18
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Paiva ALB, Matavel A, Peigneur S, Cordeiro MN, Tytgat J, Diniz MRV, de Lima ME. Differential effects of the recombinant toxin PnTx4(5-5) from the spider Phoneutria nigriventer on mammalian and insect sodium channels. Biochimie 2015; 121:326-35. [PMID: 26747232 DOI: 10.1016/j.biochi.2015.12.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 12/28/2015] [Indexed: 01/30/2023]
Abstract
The toxin PnTx4(5-5) from the spider Phoneutria nigriventer is extremely toxic/lethal to insects but has no macroscopic behavioral effects observed in mice after intracerebral injection. Nevertheless, it was demonstrated that it inhibits the N-methyl-d-aspartate (NMDA) - subtype of glutamate receptors of cultured rat hippocampal neurons. PnTx4(5-5) has 63% identity to PnTx4(6-1), another insecticidal toxin from P. nigriventer, which can slow down the sodium current inactivation in insect central nervous system, but has no effect on Nav1.2 and Nav1.4 rat sodium channels. Here, we have cloned and heterologous expressed the toxin PnTx4(5-5) in Escherichia coli. The recombinant toxin rPnTx4(5-5) was tested on the sodium channel NavBg from the cockroach Blatella germanica and on mammalian sodium channels Nav1.2-1.6, all expressed in Xenopus leavis oocytes. We showed that the toxin has different affinity and mode of action on insect and mammalian sodium channels. The most remarkable effect was on NavBg, where rPnTx4(5-5) strongly slowed down channel inactivation (EC50 = 212.5 nM), and at 1 μM caused an increase on current peak amplitude of 105.2 ± 3.1%. Interestingly, the toxin also inhibited sodium current on all the mammalian channels tested, with the higher current inhibition on Nav1.3 (38.43 ± 8.04%, IC50 = 1.5 μM). Analysis of activation curves on Nav1.3 and Nav1.5 showed that the toxin shifts channel activation to more depolarized potentials, which can explain the sodium current inhibition. Furthermore, the toxin also slightly slowed down sodium inactivation on Nav1.3 and Nav1.6 channels. As far as we know, this is the first araneomorph toxin described which can shift the sodium channel activation to more depolarized potentials and also slows down channel inactivation.
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Affiliation(s)
- Ana L B Paiva
- Departamento de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil; Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Alessandra Matavel
- Departamento de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | | | - Marta N Cordeiro
- Departamento de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Leuven, Belgium
| | - Marcelo R V Diniz
- Departamento de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | - Maria Elena de Lima
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
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Cai T, Luo J, Meng E, Ding J, Liang S, Wang S, Liu Z. Mapping the interaction site for the tarantula toxin hainantoxin-IV (β-TRTX-Hn2a) in the voltage sensor module of domain II of voltage-gated sodium channels. Peptides 2015; 68:148-56. [PMID: 25218973 DOI: 10.1016/j.peptides.2014.09.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 01/22/2023]
Abstract
Peptide toxins often have pharmacological applications and are powerful tools for investigating the structure-function relationships of voltage-gated sodium channels (VGSCs). Although a group of potential VGSC inhibitors have been reported from tarantula venoms, little is known about the mechanism of their interaction with VGSCs. In this study, we showed that hainantoxin-IV (β-TRTX-Hn2a, HNTX-IV in brief), a 35-residue peptide from Ornithoctonus hainana venom, preferentially inhibited rNav1.2, rNav1.3 and hNav1.7 compared with rNav1.4 and hNav1.5. hNav1.7 was the most sensitive to HNTX-IV (IC50∼21nM). In contrast to many other tarantula toxins that affect VGSCs, HNTX-IV at subsaturating concentrations did not alter activation and inactivation kinetics in the physiological range of voltages, while very large depolarization above +70mV could partially activate toxin-bound hNav1.7 channel, indicating that HNTX-IV acts as a gating modifier rather than a pore blocker. Site-directed mutagenesis indicated that the toxin bound to site 4, which was located on the extracellular S3-S4 linker of hNav1.7 domain II. Mutants E753Q, D816N and E818Q of hNav1.7 decreased toxin affinity for hNav1.7 by 2.0-, 3.3- and 130-fold, respectively. In silico docking indicated that a three-toed claw substructure formed by residues with close contacts in the interface between HNTX-IV and hNav1.7 domain II stabilized the toxin-channel complex, impeding movement of the domain II voltage sensor and inhibiting hNav1.7 activation. Our data provide structural details for structure-based drug design and a useful template for the design of highly selective inhibitors of a specific subtype of VGSCs.
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Affiliation(s)
- Tianfu Cai
- College of Life Sciences, Hunan Normal University, Changsha, 410081 Hunan, China
| | - Ji Luo
- College of Life Sciences, Hunan Normal University, Changsha, 410081 Hunan, China
| | - Er Meng
- Research Center of Biological Information, College of Science, National University of Defense Technology, Changsha, 410073 Hunan, China
| | - Jiuping Ding
- Key Laboratory of Molecular Biophysics, Huazhong University of Science and Technology, Ministry of Education, College of Life Science and Technology, Wuhan, Hubei 430074, China
| | - Songping Liang
- College of Life Sciences, Hunan Normal University, Changsha, 410081 Hunan, China
| | - Sheng Wang
- Key Laboratory of Molecular Biophysics, Huazhong University of Science and Technology, Ministry of Education, College of Life Science and Technology, Wuhan, Hubei 430074, China.
| | - Zhonghua Liu
- College of Life Sciences, Hunan Normal University, Changsha, 410081 Hunan, China.
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20
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Huang Y, Zhou X, Tang C, Zhang Y, Tao H, Chen P, Liu Z. Molecular basis of the inhibition of the fast inactivation of voltage-gated sodium channel Nav1.5 by tarantula toxin Jingzhaotoxin-II. Peptides 2015; 68:175-82. [PMID: 25817910 DOI: 10.1016/j.peptides.2015.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 02/07/2023]
Abstract
Jingzhaotoxin-II (JZTX-II) is a 32-residue peptide from the Chinese tarantula Chilobrachys jingzhao venom, and preferentially inhibits the fast inactivation of the voltage-gated sodium channels (VGSCs) in rat cardiac myocytes. In the present study, we elucidated the action mechanism of JZTX-II inhibiting hNav1.5, a VGSC subtype mainly distributed in human cardiac myocytes. Among the four VGSC subtypes tested, hNav1.5 was the most sensitive to JZTX-II (EC50=125±4nM). Although JZTX-II had little or no effect on steady-state inactivation of the residual currents conducted by hNav1.5, it caused a 10mV hyperpolarized shift of activation. Moreover, JZTX-II increased the recovery rate of hNav1.5 channels, which should lead to a shorter transition from the inactivation to closed state. JZTX-II dissociated from toxin-channel complex via extreme depolarization and subsequently rebound to the channel upon repolarization. Mutagenesis analyses showed that the domain IV (DIV) voltage-sensor domain (VSD) was critical for JZTX-II binding to hNav1.5 and some mutations located in S1-S2 and S3-S4 extracellular loops of hNav1.5 DIV additively reduced the toxin sensitivity of hNav1.5. Our data identified the mechanism underlying JZTX-II inhibiting hNav1.5, similar to scorpion α-toxins, involving binding to neurotoxin receptor site 3.
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Affiliation(s)
- Ying Huang
- College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China
| | - Xi Zhou
- College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China
| | - Cheng Tang
- College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China
| | - Yunxiao Zhang
- College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China
| | - Huai Tao
- Department of Biochemistry and Molecular Biology, Hunan University of Chinese Medicine, Changsha 410208, Hunan, China
| | - Ping Chen
- College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China
| | - Zhonghua Liu
- College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
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21
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Berkut AA, Peigneur S, Myshkin MY, Paramonov AS, Lyukmanova EN, Arseniev AS, Grishin EV, Tytgat J, Shenkarev ZO, Vassilevski AA. Structure of membrane-active toxin from crab spider Heriaeus melloteei suggests parallel evolution of sodium channel gating modifiers in Araneomorphae and Mygalomorphae. J Biol Chem 2014; 290:492-504. [PMID: 25352595 DOI: 10.1074/jbc.m114.595678] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We present a structural and functional study of a sodium channel activation inhibitor from crab spider venom. Hm-3 is an insecticidal peptide toxin consisting of 35 amino acid residues from the spider Heriaeus melloteei (Thomisidae). We produced Hm-3 recombinantly in Escherichia coli and determined its structure by NMR spectroscopy. Typical for spider toxins, Hm-3 was found to adopt the so-called "inhibitor cystine knot" or "knottin" fold stabilized by three disulfide bonds. Its molecule is amphiphilic with a hydrophobic ridge on the surface enriched in aromatic residues and surrounded by positive charges. Correspondingly, Hm-3 binds to both neutral and negatively charged lipid vesicles. Electrophysiological studies showed that at a concentration of 1 μm Hm-3 effectively inhibited a number of mammalian and insect sodium channels. Importantly, Hm-3 shifted the dependence of channel activation to more positive voltages. Moreover, the inhibition was voltage-dependent, and strong depolarizing prepulses attenuated Hm-3 activity. The toxin is therefore concluded to represent the first sodium channel gating modifier from an araneomorph spider and features a "membrane access" mechanism of action. Its amino acid sequence and position of the hydrophobic cluster are notably different from other known gating modifiers from spider venom, all of which are described from mygalomorph species. We hypothesize parallel evolution of inhibitor cystine knot toxins from Araneomorphae and Mygalomorphae suborders.
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Affiliation(s)
- Antonina A Berkut
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia, Moscow Institute of Physics and Technology (State University), 117303 Moscow, Russia, and
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven, 3000 Leuven, Belgium
| | - Mikhail Yu Myshkin
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia, Moscow Institute of Physics and Technology (State University), 117303 Moscow, Russia, and
| | - Alexander S Paramonov
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Ekaterina N Lyukmanova
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Alexander S Arseniev
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia, Moscow Institute of Physics and Technology (State University), 117303 Moscow, Russia, and
| | - Eugene V Grishin
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven, 3000 Leuven, Belgium
| | - Zakhar O Shenkarev
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Alexander A Vassilevski
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia,
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22
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Meng E, Cai TF, Zhang H, Tang S, Li MJ, Li WY, Huang PF, Liu K, Wu L, Zhu LY, Liu L, Peng K, Dai XD, Jiang H, Zeng XZ, Liang SP, Zhang DY. Screening for voltage-gated sodium channel interacting peptides. Sci Rep 2014; 4:4569. [PMID: 24691553 PMCID: PMC3972499 DOI: 10.1038/srep04569] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 03/18/2014] [Indexed: 11/29/2022] Open
Abstract
The voltage-gated sodium channel (VGSC) interacting peptide is of special interest for both basic research and pharmaceutical purposes. In this study, we established a yeast-two-hybrid based strategy to detect the interaction(s) between neurotoxic peptide and the extracellular region of VGSC. Using a previously reported neurotoxin JZTX-III as a model molecule, we demonstrated that the interactions between JZTX-III and the extracellular regions of its target hNav1.5 are detectable and the detected interactions are directly related to its activity. We further applied this strategy to the screening of VGSC interacting peptides. Using the extracellular region of hNav1.5 as the bait, we identified a novel sodium channel inhibitor SSCM-1 from a random peptide library. This peptide selectively inhibits hNav1.5 currents in the whole-cell patch clamp assays. This strategy might be used for the large scale screening for target-specific interacting peptides of VGSCs or other ion channels.
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Affiliation(s)
- Er Meng
- 1] State Key Laboratory of High Performance Computing, Research Center of Biological Information, National University of Defense Technology, Changsha, Hunan 410073, China [2]
| | - Tian-Fu Cai
- 1] Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China [2]
| | - Hui Zhang
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Si Tang
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Meng-Jie Li
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Wen-Ying Li
- State Key Laboratory of High Performance Computing, Research Center of Biological Information, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Peng-Fei Huang
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Kai Liu
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Lei Wu
- State Key Laboratory of High Performance Computing, Research Center of Biological Information, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Ling-Yun Zhu
- State Key Laboratory of High Performance Computing, Research Center of Biological Information, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Long Liu
- State Key Laboratory of High Performance Computing, Research Center of Biological Information, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Kuan Peng
- Core Facilities of Biotechnology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China
| | - Xian-Dong Dai
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China
| | - Hui Jiang
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China
| | - Xiong-Zhi Zeng
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Song-Ping Liang
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Dong-Yi Zhang
- State Key Laboratory of High Performance Computing, Research Center of Biological Information, National University of Defense Technology, Changsha, Hunan 410073, China
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23
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Peng X, Zhang Y, Liu J, Yu H, Chen J, Lei Q, Wang X, Liang S. Physiological and Biochemical Analysis to Reveal the Molecular Basis for Black Widow Spiderling Toxicity. J Biochem Mol Toxicol 2014; 28:198-205. [DOI: 10.1002/jbt.21553] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/21/2014] [Accepted: 02/01/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Xiaozhen Peng
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education; College of Life Sciences, Hunan Normal University; Changsha Hunan 410081 People's Republic of China
| | - Yiya Zhang
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education; College of Life Sciences, Hunan Normal University; Changsha Hunan 410081 People's Republic of China
| | - Jinyan Liu
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education; College of Life Sciences, Hunan Normal University; Changsha Hunan 410081 People's Republic of China
| | - Hai Yu
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education; College of Life Sciences, Hunan Normal University; Changsha Hunan 410081 People's Republic of China
| | - Jia Chen
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education; College of Life Sciences, Hunan Normal University; Changsha Hunan 410081 People's Republic of China
| | - Qian Lei
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education; College of Life Sciences, Hunan Normal University; Changsha Hunan 410081 People's Republic of China
| | - Xianchun Wang
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education; College of Life Sciences, Hunan Normal University; Changsha Hunan 410081 People's Republic of China
| | - Songping Liang
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education; College of Life Sciences, Hunan Normal University; Changsha Hunan 410081 People's Republic of China
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25
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Tao H, Chen JJ, Xiao YC, Wu YY, Su HB, Li D, Wang HY, Deng MC, Wang MC, Liu ZH, Liang SP. Analysis of the Interaction of Tarantula Toxin Jingzhaotoxin-III (β-TRTX-Cj1α) with the Voltage Sensor of Kv2.1 Uncovers the Molecular Basis for Cross-Activities on Kv2.1 and Nav1.5 Channels. Biochemistry 2013; 52:7439-48. [DOI: 10.1021/bi4006418] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Huai Tao
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
- Department
of Biochemistry and Molecular Biology, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Jin J. Chen
- College
of Biology Science and Technology, Hunan Agricultural University, Changsha, Hunan 410128, China
| | - Yu C. Xiao
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Yuan Y. Wu
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Hai B Su
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Dan Li
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Heng Y. Wang
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Mei C. Deng
- Department
of Biochemistry, School of Biological Science and Technology, Central South University, Changsha, Hunan 410013, China
| | - Mei C. Wang
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Zhong H. Liu
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Song P. Liang
- Key
Laboratory of Protein Chemistry and Developmental Biology of Ministry
of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
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26
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Discovery of a selective NaV1.7 inhibitor from centipede venom with analgesic efficacy exceeding morphine in rodent pain models. Proc Natl Acad Sci U S A 2013; 110:17534-9. [PMID: 24082113 DOI: 10.1073/pnas.1306285110] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Loss-of-function mutations in the human voltage-gated sodium channel NaV1.7 result in a congenital indifference to pain. Selective inhibitors of NaV1.7 are therefore likely to be powerful analgesics for treating a broad range of pain conditions. Herein we describe the identification of µ-SLPTX-Ssm6a, a unique 46-residue peptide from centipede venom that potently inhibits NaV1.7 with an IC50 of ∼25 nM. µ-SLPTX-Ssm6a has more than 150-fold selectivity for NaV1.7 over all other human NaV subtypes, with the exception of NaV1.2, for which the selectivity is 32-fold. µ-SLPTX-Ssm6a contains three disulfide bonds with a unique connectivity pattern, and it has no significant sequence homology with any previously characterized peptide or protein. µ-SLPTX-Ssm6a proved to be a more potent analgesic than morphine in a rodent model of chemical-induced pain, and it was equipotent with morphine in rodent models of thermal and acid-induced pain. This study establishes µ-SPTX-Ssm6a as a promising lead molecule for the development of novel analgesics targeting NaV1.7, which might be suitable for treating a wide range of human pain pathologies.
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27
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Rong M, Duan Z, Chen J, Li J, Xiao Y, Liang S. Native pyroglutamation of huwentoxin-IV: a post-translational modification that increases the trapping ability to the sodium channel. PLoS One 2013; 8:e65984. [PMID: 23826086 PMCID: PMC3691182 DOI: 10.1371/journal.pone.0065984] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 04/29/2013] [Indexed: 11/23/2022] Open
Abstract
Huwentoxin-IV (HWTX-IV), a tetrodotoxin-sensitive (TTX-s) sodium channel antagonist, is found in the venom of the Chinese spider Ornithoctonus huwena. A naturally modified HWTX-IV (mHWTX-IV), having a molecular mass 18 Da lower than HWTX-IV, has also been isolated from the venom of the same spider. By a combination of enzymatic fragmentation and MS/MS de novo sequencing, mHWTX-IV has been shown to have the same amino acid sequence as that of HWTX-IV, except that the N-terminal glutamic acid replaced by pyroglutamic acid. mHWTX-IV inhibited tetrodotoxin-sensitive voltage-gated sodium channels of dorsal root ganglion neurons with an IC50 nearly equal to native HWTX-IV. mHWTX-IV showed the same activation and inactivation kinetics seen for native HWTX-IV. In contrast with HWTX-IV, which dissociates at moderate voltage depolarization voltages (+50 mV, 180000 ms), mHWTX-IV inhibition of TTX-sensitive sodium channels is not reversed by strong depolarization voltages (+200 mV, 500 ms). Recovery of Nav1.7current was voltage-dependent and was induced by extreme depolarization in the presence of HWTX-IV, but no obvious current was elicited after application of mHWTX-IV. Our data indicate that the N-terminal modification of HWTX-IV gives the peptide toxin a greater ability to trap the voltage sensor in the sodium channel. Loss of a negative charge, caused by cyclization at the N-terminus, is a possible reason why the modified toxin binds much stronger. To our knowledge, this is the first report of a pyroglutamic acid residue in a spider toxin; this modification seems to increase the trapping ability of the voltage sensor in the sodium channel.
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Affiliation(s)
- Mingqiang Rong
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China
| | - Zhigui Duan
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Juliang Chen
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Jianglin Li
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Yuchen Xiao
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Songping Liang
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, China
- * E-mail:
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SUN MEINA, ZHAO XUEJIAO, ZHAO HANDONG, ZHANG WEIGUANG, LI FENGLAN, CHEN MINGZI, LI HUI, LI GUANGCHAO. Recombinant Escherichia coli Trx-JZTX-III represses the proliferation of mouse hepatocellular carcinoma cells through induction of cell cycle arrest. Mol Med Rep 2013; 7:1800-4. [DOI: 10.3892/mmr.2013.1432] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Accepted: 03/22/2013] [Indexed: 11/05/2022] Open
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Abstract
Venomous animals use a highly complex cocktails of proteins, peptides and small molecules to subdue and kill their prey. As such, venoms represent highly valuable combinatorial peptide libraries, displaying an extensive range of pharmacological activities, honed by natural selection. Modern analytical technologies enable us to take full advantage of this vast pharmacological cornucopia in the hunt for novel drug leads. Spider venoms represent a resource of several million peptides, which selectively target specific subtypes of ion channels. Structure-function studies of spider toxins are leading not only to the discovery of novel molecules, but also to novel therapeutic routes for cardiovascular diseases, cancer, neuromuscular diseases, pain and to a variety of other pathological conditions. This review presents an overview of spider peptide toxins as candidates for therapeutics and focuses on their applications in the discovery of novel mechanisms of analgesia.
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Affiliation(s)
- Pierre Escoubas
- University of Nice - Sophia Antipolis, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC) - CNRS UMR6097, 660 Route des Lucioles, 06560 Valbonne, France +33 04 93 95 77 35 ; +33 04 93 95 77 08 ;
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30
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Nardi A, Damann N, Hertrampf T, Kless A. Advances in targeting voltage-gated sodium channels with small molecules. ChemMedChem 2012; 7:1712-40. [PMID: 22945552 DOI: 10.1002/cmdc.201200298] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/30/2012] [Indexed: 12/19/2022]
Abstract
Blockade of voltage-gated sodium channels (VGSCs) has been used successfully in the clinic to enable control of pathological firing patterns that occur in conditions as diverse as chronic pain, epilepsy, and arrhythmias. Herein we review the state of the art in marketed sodium channel inhibitors, including a brief compendium of their binding sites and of the cellular and molecular biology of sodium channels. Despite the preferential action of this drug class toward over-excited cells, which significantly limits potential undesired side effects on other cells, the need to develop a second generation of sodium channel inhibitors to overcome their critical clinical shortcomings is apparent. Current approaches in drug discovery to deliver novel and truly innovative sodium channel inhibitors is next presented by surveying the most recent medicinal chemistry breakthroughs in the field of small molecules and developments in automated patch-clamp platforms. Various strategies aimed at identifying small molecules that target either particular isoforms of sodium channels involved in specific diseases or anomalous sodium channel currents, irrespective of the isoform by which they have been generated, are critically discussed and revised.
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Affiliation(s)
- Antonio Nardi
- Global Drug Discovery, Department of Medicinal Chemistry, Grünenthal, Zieglerstrasse 6, 52078 Aachen, Germany.
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31
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Yang S, Liu Z, Xiao Y, Li Y, Rong M, Liang S, Zhang Z, Yu H, King GF, Lai R. Chemical punch packed in venoms makes centipedes excellent predators. Mol Cell Proteomics 2012; 11:640-50. [PMID: 22595790 DOI: 10.1074/mcp.m112.018853] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Centipedes are excellent predatory arthropods that inject venom to kill or immobilize their prey. Although centipedes have long been known to be venomous, their venoms remain largely unexplored. The chemical components responsible for centipede predation and the functional mechanisms are unknown. Twenty-six neurotoxin-like peptides belonging to ten groups were identified from the centipede venoms, Scolopendra subspinipes mutilans L. Koch by peptidomics combined with transcriptome analysis, revealing the diversity of neurotoxins. These neurotoxins each contain two to four intramolecular disulfide bridges, and in most cases the disulfide framework is different from that found in neurotoxins from the venoms of spiders, scorpions, marine cone snails, sea anemones, and snakes (5S animals). Several neurotoxins contain potential insecticidal abilities, and they are found to act on voltage-gated sodium, potassium, and calcium channels, respectively. Although these neurotoxins are functionally similar to the disulfide-rich neurotoxins found in the venoms of 5S animals in that they modulate the activity of voltage-gated ion channels, in almost all cases the primary structures of the centipede venom peptides are unique. This represents an interesting case of convergent evolution in which different venomous animals have evolved different molecular strategies for targeting the same ion channels in prey and predators. Moreover, the high level of biochemical diversity revealed in this study suggests that centipede venoms might be attractive subjects for prospecting and screening for peptide candidates with potential pharmaceutical or agrochemical applications.
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Affiliation(s)
- Shilong Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming 650223, Yunnan, China
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32
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Yuan C, Liu Z, Hu W, Gao T, Liang S. JZTX-XIII, a Kv channel gating modifier toxin from Chinese tarantula Chilobrachys jingzhao. Toxicon 2012; 59:265-71. [DOI: 10.1016/j.toxicon.2011.11.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 10/22/2011] [Accepted: 11/29/2011] [Indexed: 10/14/2022]
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33
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Rong M, Chen J, Tao H, Wu Y, Jiang P, Lu M, Su H, Chi Y, Cai T, Zhao L, Zeng X, Xiao Y, Liang S. Molecular basis of the tarantula toxin jingzhaotoxin-III (β-TRTX-Cj1α) interacting with voltage sensors in sodium channel subtype Nav1.5. FASEB J 2011; 25:3177-85. [PMID: 21665957 DOI: 10.1096/fj.10-178848] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
With conserved structural scaffold and divergent electrophysiological functions, animal toxins are considered powerful tools for investigating the basic structure-function relationship of voltage-gated sodium channels. Jingzhaotoxin-III (β-TRTX-Cj1α) is a unique sodium channel gating modifier from the tarantula Chilobrachys jingzhao, because the toxin can selectively inhibit the activation of cardiac sodium channel but not neuronal subtypes. However, the molecular basis of JZTX-III interaction with sodium channels remains unknown. In this study, we showed that JZTX-III was efficiently expressed by the secretory pathway in yeast. Alanine-scanning analysis indicated that 2 acidic residues (Asp1, Glu3) and an exposed hydrophobic patch, formed by 4 Trp residues (residues 8, 9, 28 and 30), play important roles in the binding of JZTX-III to Nav1.5. JZTX-III docked to the Nav1.5 DIIS3-S4 linker. Mutations S799A, R800A, and L804A could additively reduce toxin sensitivity of Nav1.5. We also demonstrated that the unique Arg800, not emerging in other sodium channel subtypes, is responsible for JZTX-III selectively interacting with Nav1.5. The reverse mutation D816R in Nav1.7 greatly increased the sensitivity of the neuronal subtype to JZTX-III. Conversely, the mutation R800D in Nav1.5 decreased JZTX-III's IC₅₀ by 72-fold. Therefore, our results indicated that JZTX-III is a site 4 toxin, but does not possess the same critical residues on sodium channels as other site 4 toxins. Our data also revealed the underlying mechanism for JZTX-III to be highly specific for the cardiac sodium channel.
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Affiliation(s)
- Mingqiang Rong
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, China
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Lee S, Milescu M, Jung HH, Lee JY, Bae CH, Lee CW, Kim HH, Swartz KJ, Kim JI. Solution structure of GxTX-1E, a high-affinity tarantula toxin interacting with voltage sensors in Kv2.1 potassium channels . Biochemistry 2010; 49:5134-42. [PMID: 20509680 DOI: 10.1021/bi100246u] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
GxTX-1E is a neurotoxin recently isolated from Plesiophrictus guangxiensis venom that inhibits the Kv2.1 channel in pancreatic beta-cells. The sequence of the toxin is related to those of previously studied tarantula toxins that interact with the voltage sensors in Kv channels, and GxTX-1E interacts with the Kv2.1 channel with unusually high affinity, making it particularly useful for structural and mechanistic studies. Here we determined the three-dimensional solution structure of GxTX-1E using NMR spectroscopy and compared it to that of several related tarantula toxins. The molecular structure of GxTX-1E is similar to those of tarantula toxins that target voltage sensors in Kv channels in that it contains an ICK motif, composed of beta-strands, and contains a prominent cluster of solvent-exposed hydrophobic residues surrounded by polar residues. When compared with the structure of SGTx1, a toxin for which mutagenesis data are available, the residue compositions of the two toxins are distinct in regions that are critical for activity, suggesting that their modes of binding to voltage sensors may be different. Interestingly, the structural architecture of GxTX-1E is also similar to that of JZTX-III, a tarantula toxin that interacts with Kv2.1 with low affinity. The most striking structural differences between GxTX-1E and JZTX-III are found in the orientation between the first and second cysteine loops and the C-terminal region of the toxins, suggesting that these regions of GxTX-1E are responsible for its high affinity.
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Affiliation(s)
- Seungkyu Lee
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea
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35
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Nikolsky AS, Billen B, Vassilevski AA, Filkin SY, Tytgat J, Grishin EV. Voltage-gated sodium channels are targets for toxins from the venom of the spider Heriaeus melloteei. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2009. [DOI: 10.1134/s1990747809030027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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36
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Deng M, Kuang F, Sun Z, Tao H, Cai T, Zhong L, Chen Z, Xiao Y, Liang S. Jingzhaotoxin-IX, a novel gating modifier of both sodium and potassium channels from Chinese tarantula Chilobrachys jingzhao. Neuropharmacology 2009; 57:77-87. [DOI: 10.1016/j.neuropharm.2009.04.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2008] [Revised: 04/19/2009] [Accepted: 04/20/2009] [Indexed: 12/19/2022]
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You D, Hong J, Rong M, Yu H, Liang S, Ma Y, Yang H, Wu J, Lin D, Lai R. The first gene-encoded amphibian neurotoxin. J Biol Chem 2009; 284:22079-22086. [PMID: 19535333 DOI: 10.1074/jbc.m109.013276] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many gene-encoded neurotoxins with various functions have been discovered in fish, reptiles, and mammals. A novel 60-residue neurotoxin peptide (anntoxin) that inhibited tetrodotoxin-sensitive (TTX-S) voltage-gated sodium channel (VGSC) was purified and characterized from the skin secretions of the tree frog Hyla annectans (Jerdon). This is the first gene-encoded neurotoxin found in amphibians. The IC50 of anntoxin for the TTX-S channel was about 3.4 microM. Anntoxin shares sequence homology with Kunitz-type toxins but contains only two of three highly conserved cysteine bridges, which are typically found in these small, basic neurotoxin modules, i.e. snake dendrotoxins. Anntoxin showed an inhibitory ability against trypsin with an inhibitory constant (Ki) of 0.025 microM. Anntoxin was distributed in skin, brain, stomach, and liver with a concentration of 25, 7, 3, and 2 microg/g wet tissue, respectively. H. annectans lives on trees or other plants for its entire life cycle, and its skin contains the largest amount of anntoxin, which possibly helps defend against various aggressors or predators. A low dose of anntoxin was found to induce lethal toxicity for several potential predators, including the insect, snake, bird, and mouse. The tissue distribution and functional properties of the current toxin may provide insights into the ecological adaptation of tree-living amphibians.
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Affiliation(s)
- Dewen You
- Biotoxin Units of Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan; Graduate School of the Chinese Academy of Sciences, Beijing 100009, China
| | - Jing Hong
- Graduate School of the Chinese Academy of Sciences, Beijing 100009, China; Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203
| | - Mingqiang Rong
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081
| | - Haining Yu
- College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, Hebei
| | - Songping Liang
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081
| | - Yufang Ma
- Biotoxin Units of Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan; Graduate School of the Chinese Academy of Sciences, Beijing 100009, China
| | - Hailong Yang
- Biotoxin Units of Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan; Graduate School of the Chinese Academy of Sciences, Beijing 100009, China
| | - Jing Wu
- Biotoxin Units of Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan; Graduate School of the Chinese Academy of Sciences, Beijing 100009, China
| | - Donghai Lin
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203
| | - Ren Lai
- Biotoxin Units of Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan
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Chen J, Zhang Y, Rong M, Zhao L, Jiang L, Zhang D, Wang M, Xiao Y, Liang S. Expression and characterization of jingzhaotoxin-34, a novel neurotoxin from the venom of the tarantula Chilobrachys jingzhao. Peptides 2009; 30:1042-8. [PMID: 19463735 DOI: 10.1016/j.peptides.2009.02.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Revised: 02/23/2009] [Accepted: 02/26/2009] [Indexed: 11/30/2022]
Abstract
Jingzhaotoxin-34 (JZTX-34) is a 35-residue polypeptide from the venom of Chinese tarantula Chilobrachys jingzhao. Our previous work reported its full-length cDNA sequence encoding a precursor with 87 residues. In this study we report the protein expression and biological function characterization. The toxin was efficiently expressed by the secretary pathway in yeast. Under whole-cell patch-clamp mode, the expressed JZTX-34 was able to inhibit tetrodotoxin-sensitive (TTX-S) sodium currents (IC(50) approximately 85 nM) while having no significant effects on tetrodotoxin-resistant (TTX-R) sodium currents on rat dorsal root ganglion neurons. The inhibition of TTX-S sodium channels was completely reversed by strong depolarization (+120 mV). Toxin treatment altered neither channel activation and inactivation kinetics nor recovery rate from inactivation. However, it is interesting to note that in contrast to huwentoxin-IV, a recently identified receptor site-4 toxin from Ornithoctonus huwena venom, 100 nM JZTX-34 caused a negative shift of steady-state inactivation curve of TTX-S sodium channels by approximately 10 mV. The results indicated that JZTX-34 might inhibit mammalian sensory neuronal sodium channels through a mechanism similar to HWTX-IV by trapping the IIS4 voltage sensor in the resting conformation, but their binding sites should not overlay completely.
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Affiliation(s)
- Jinjun Chen
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, PR China
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Chen J, Zhao L, Jiang L, Meng E, Zhang Y, Xiong X, Liang S. Transcriptome analysis revealed novel possible venom components and cellular processes of the tarantula Chilobrachys jingzhao venom gland. Toxicon 2008; 52:794-806. [DOI: 10.1016/j.toxicon.2008.08.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Revised: 08/03/2008] [Accepted: 08/12/2008] [Indexed: 11/30/2022]
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Wang M, Liu Q, Luo H, Li J, Tang J, Xiao Y, Liang S. Jingzhaotoxin-II, a novel tarantula toxin preferentially targets rat cardiac sodium channel. Biochem Pharmacol 2008; 76:1716-27. [DOI: 10.1016/j.bcp.2008.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2008] [Revised: 09/04/2008] [Accepted: 09/05/2008] [Indexed: 11/26/2022]
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Structure, function, and modification of the voltage sensor in voltage-gated ion channels. Cell Biochem Biophys 2008; 52:149-74. [PMID: 18989792 DOI: 10.1007/s12013-008-9032-5] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2008] [Indexed: 01/12/2023]
Abstract
Voltage-gated ion channels are crucial for both neuronal and cardiac excitability. Decades of research have begun to unravel the intriguing machinery behind voltage sensitivity. Although the details regarding the arrangement and movement in the voltage-sensor domain are still debated, consensus is slowly emerging. There are three competing conceptual models: the helical-screw, the transporter, and the paddle model. In this review we explore the structure of the activated voltage-sensor domain based on the recent X-ray structure of a chimera between Kv1.2 and Kv2.1. We also present a model for the closed state. From this we conclude that upon depolarization the voltage sensor S4 moves approximately 13 A outwards and rotates approximately 180 degrees, thus consistent with the helical-screw model. S4 also moves relative to S3b which is not consistent with the paddle model. One interesting feature of the voltage sensor is that it partially faces the lipid bilayer and therefore can interact both with the membrane itself and with physiological and pharmacological molecules reaching the channel from the membrane. This type of channel modulation is discussed together with other mechanisms for how voltage-sensitivity is modified. Small effects on voltage-sensitivity can have profound effects on excitability. Therefore, medical drugs designed to alter the voltage dependence offer an interesting way to regulate excitability.
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Discovery of a distinct superfamily of Kunitz-type toxin (KTT) from tarantulas. PLoS One 2008; 3:e3414. [PMID: 18923708 PMCID: PMC2561067 DOI: 10.1371/journal.pone.0003414] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Accepted: 09/16/2008] [Indexed: 12/02/2022] Open
Abstract
Background Kuntiz-type toxins (KTTs) have been found in the venom of animals such as snake, cone snail and sea anemone. The main ancestral function of Kunitz-type proteins was the inhibition of a diverse array of serine proteases, while toxic activities (such as ion-channel blocking) were developed under a variety of Darwinian selection pressures. How new functions were grafted onto an old protein scaffold and what effect Darwinian selection pressures had on KTT evolution remains a puzzle. Principal Findings Here we report the presence of a new superfamily of KTTs in spiders (Tarantulas: Ornithoctonus huwena and Ornithoctonus hainana), which share low sequence similarity to known KTTs and is clustered in a distinct clade in the phylogenetic tree of KTT evolution. The representative molecule of spider KTTs, HWTX-XI, purified from the venom of O. huwena, is a bi-functional protein which is a very potent trypsin inhibitor (about 30-fold more strong than BPTI) as well as a weak Kv1.1 potassium channel blocker. Structural analysis of HWTX-XI in 3-D by NMR together with comparative function analysis of 18 expressed mutants of this toxin revealed two separate sites, corresponding to these two activities, located on the two ends of the cone-shape molecule of HWTX-XI. Comparison of non-synonymous/synonymous mutation ratios (ω) for each site in spider and snake KTTs, as well as PBTI like body Kunitz proteins revealed high Darwinian selection pressure on the binding sites for Kv channels and serine proteases in snake, while only on the proteases in spider and none detected in body proteins, suggesting different rates and patterns of evolution among them. The results also revealed a series of key events in the history of spider KTT evolution, including the formation of a novel KTT family (named sub-Kuntiz-type toxins) derived from the ancestral native KTTs with the loss of the second disulfide bridge accompanied by several dramatic sequence modifications. Conclusions/Significance These finding illustrate that the two activity sites of Kunitz-type toxins are functionally and evolutionally independent and provide new insights into effects of Darwinian selection pressures on KTT evolution, and mechanisms by which new functions can be grafted onto old protein scaffolds.
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44
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Wang M, Diao J, Li J, Tang J, Lin Y, Hu W, Zhang Y, Xiao Y, Liang S. JZTX-IV, a unique acidic sodium channel toxin isolated from the spider Chilobrachys jingzhao. Toxicon 2008; 52:871-80. [PMID: 18848955 DOI: 10.1016/j.toxicon.2008.08.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 08/27/2008] [Accepted: 08/29/2008] [Indexed: 11/27/2022]
Abstract
Neurotoxins are important tools to explore the structure and function relationship of different ion channels. From the venom of Chinese spider Chilobrachys jingzhao, a novel toxin, Jingzhaotoxin-IV (JZTX-IV), is isolated and characterized. It consists of 34 amino acid residues including six acidic residues clustered with negative charge (pI=4.29). The full-length cDNA of JZTX-IV encodes an 86-amino acid precursor containing a signal peptide of 21 residues, a mature peptide of 34 residues and an intervening sequence of 29 residues with terminal Lys-Gly as the signal of amidation. Under whole-cell patch clamp conditions, JZTX-IV inhibits current and slows the inactivation of sodium channels by shifting the voltage dependence of activation to more depolarized potentials on DRG neurons, therefore, differs from the classic site 4 toxins that shift voltage dependence of activation in the opposite direction. In addition, JZTX-IV shows a slowing inactivation of sodium channel with a hyperpolarizing shift of the steady-state inactivation on acutely isolated rat cardiac cell and DRG neurons, differs from the classic site 3 toxins that do not affect the steady-state of inactivation. At high concentration, JZTX-IV has no significant effect on tetrodotoxin-resistant (TTX-R) sodium channels on rat DRG neurons and tetrodotoxin-sensitive (TTX-S) sodium channels on hippocampal neurons. Our data establish that, contrary to known toxins, JZTX-IV neither binds to the previously characterized classic site 4, nor site 3 by modifying channel gating, thus making it a novel probe of channel gating in sodium channels with potential to shed new light on this process.
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Affiliation(s)
- Meichi Wang
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, The College of Life Science, Hunan Normal University, Lushan Road, Yuelu District, Changsha, Hunan 410081, China
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Liao Z, Cao J, Li S, Yan X, Hu W, He Q, Chen J, Tang J, Xie J, Liang S. Proteomic and peptidomic analysis of the venom from Chinese tarantulaChilobrachys jingzhao. Proteomics 2007; 7:1892-907. [PMID: 17476710 DOI: 10.1002/pmic.200600785] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Chinese tarantula, Chilobrachys jingzhao is one of the most venomous spiders in southern China and its venom is a mixture of various compounds with diversified biological activities. The proteome of C. jingzhao venom was analyzed by proteomic techniques. Proteins with molecular weight of over 10 kDa, indicated by gel-filtration and SDS-PAGE, were analyzed using 2-DE and MALDI-TOF/TOF and LC/ESI-Q-TOF MS. More than 90 proteins were detected, with 47 confirmed by sequence similarity search using mass spectrum driven basic local alignment search tool (MS BLAST). On the other hand, peptides with MW lower than 10 kDa were separated by HPLC and identified by MALDI-TOF MS and Edman degradation sequencing. About 120 peptides were detected, 60 of which were fully or partially sequenced. Our results indicate that peptides with MW lower than 10 kDa are the major components in the crude venom of C. jingzhao. Like those of other tarantulas, these peptides are very likely to act on various ion channels. These results pave a way for further detailed structure-function correlation analysis of the individual toxins present in the venom of C. jingzhao.
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Affiliation(s)
- Zhi Liao
- College of Life Sciences, Peking University, Beijing, People's Republic of China
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Xiao Y, Li J, Deng M, Dai C, Liang S. Characterization of the excitatory mechanism induced by Jingzhaotoxin-I inhibiting sodium channel inactivation. Toxicon 2007; 50:507-17. [PMID: 17618665 DOI: 10.1016/j.toxicon.2007.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2007] [Revised: 04/15/2007] [Accepted: 04/23/2007] [Indexed: 10/23/2022]
Abstract
We have recently isolated a peptide neurotoxin, Jingzhaotoxin-I (JZTX-I), from Chinese tarantula Chilobrachys jingzhao venom that preferentially inhibits cardiac sodium channel inactivation and may define a new subclass of spider sodium channel toxins. In this study, we found that in contrast to other spider sodium channel toxins acting presynaptically rather than postsynaptically, JZTX-I augmented frog end-plate potential amplitudes and caused an increase in both nerve mediated and unmediated muscle twitches. Although JZTX-I does not negatively shift sodium channel activation threshold, an evident increase in muscle fasciculation was detected. In adult rat dorsal root ganglion neurons JZTX-I (1 microM) induced a significant sustained tetrodotoxin-sensitive (TTX-S) current that did not decay completely during 500 ms and was inhibited by 0.1 microM TTX or depolarization due to voltage-dependent acceleration of toxin dissociation. Moreover, JZTX-I decreased closed-state inactivation and increased the rate of recovery of sodium channels, which led to an augmentation in TTX-S ramp currents and decreasing the amount of inactivation in a use-dependant manner. Together, these data suggest that JZTX-I acted both presynaptically and postsynaptically and facilitated the neurotransmitter release by biasing the activities of sodium channels towards open state. These actions are similar to those of scorpion alpha-toxin Lqh II.
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Affiliation(s)
- Yucheng Xiao
- Life Sciences College, Hunan Normal University, Changsha, Hunan 410081, PR China
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47
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Estrada G, Villegas E, Corzo G. Spider venoms: a rich source of acylpolyamines and peptides as new leads for CNS drugs. Nat Prod Rep 2007; 24:145-61. [PMID: 17268611 DOI: 10.1039/b603083c] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Advances in NMR and mass spectrometry as well as in peptide biochemistry coupled to modern methods in electrophysiology have permitted the isolation and identification of numerous products from spider venoms, previously explored due to technical limitations. The chemical composition of spider venoms is diverse, ranging from low molecular weight organic compounds such as acylpolyamines to complex peptides. First, acylpolyamines (< 1000 Da) have an aromatic moiety linked to a hydrophilic lateral chain. They were characterized for the first time in spider venoms and are ligand-gated ion channel antagonists, which block mainly postsynaptic glutamate receptors in invertebrate and vertebrate nervous systems. Acylpolyamines represent the vast majority of organic components from the spider venom. Acylpolyamine analogues have proven to suppress hippocampal epileptic discharges. Moreover, acylpolyamines could suppress excitatory postsynaptic currents inducing Ca+ accumulation in neurons leading to protection against a brain ischemic insult. Second, short spider peptides (< 6000 Da) modulate ionic currents in Ca2+, Na+, or K+ voltage-gated ion channels. Such peptides may contain from three to four disulfide bridges. Some spider peptides act specifically to discriminate among Ca2+, Na+, or K+ ion channel subtypes. Their selective affinities for ion channel subfamilies are functional for mapping excitable cells. Furthermore, several of these peptides have proven to hyperpolarize peripheral neurons, which are associated with supplying sensation to the skin and skeletal muscles. Some spider N-type calcium ion channel blockers may be important for the treatment of chronic pain. A special group of spider peptides are the amphipathic and positively charged peptides. Their secondary structure is alpha-helical and they insert into the lipid cell membrane of eukaryotic or prokaryotic cells leading to the formation of pores and subsequently depolarizing the cell membrane. Acylpolyamines and peptides from spider venoms represent an interesting source of molecules for the design of novel pharmaceutical drugs.
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Affiliation(s)
- Georgina Estrada
- Instituto de Biotecnología, UNAM, Avenida Universidad 2001, Cuernavaca, Morelos 62210, México
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Yuan C, Yang S, Liao Z, Liang S. Effects and mechanism of Chinese tarantula toxins on the Kv2.1 potassium channels. Biochem Biophys Res Commun 2006; 352:799-804. [PMID: 17150181 DOI: 10.1016/j.bbrc.2006.11.086] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 11/17/2006] [Indexed: 11/21/2022]
Abstract
Three neurotoxins, Jingzhaotoxin-I, -III, and -V (JZTX-I, -III, and -V), isolated from the venom of the Chinese tarantula Chilobrachys Jingzhao, are 29-36-amino acid peptides. Electrophysiological recordings carried out in Xenopus laevis oocytes show that these toxins acted as gating modifier of voltage-dependent K+ channels. They slow the rate of Kv2.1 channel activation and increase the tail current deactivation, suggesting that toxin-bound channels can still open but are modified. JZTX-III selectively inhibits Kv2.1 channels, and JZTX-V exhibits a higher affinity to Kv4.2 channels than to Kv2.1 channels, whereas JZTX-I inhibits Kv2.1 and Kv4.1 channels with low affinity. Structure-function analysis indicates that electrostatic interactions can benefit for toxin affinity and the feature of electrostatic anisotropy may be correlated with the different affinity of the toxins for the Kv2.1 and Kv4.1 channels. Furthermore, phylogenetic analysis of these and other gating modifiers provides clues for the exploration of toxin-channel interaction.
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Affiliation(s)
- Chunhua Yuan
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, Life Science College, Hunan Normal University, Changsha 410081, PR China
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49
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Escoubas P. Molecular diversification in spider venoms: a web of combinatorial peptide libraries. Mol Divers 2006; 10:545-54. [PMID: 17096075 DOI: 10.1007/s11030-006-9050-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Accepted: 03/28/2006] [Indexed: 01/19/2023]
Abstract
Spider venoms are a rich source of novel pharmacologically and agrochemically interesting compounds that have received increased attention from pharmacologists and biochemists in recent years. The application of technologies derived from genomics and proteomics have led to the discovery of the enormous molecular diversity of those venoms, which consist mainly of peptides and proteins. The molecular diversity of spider peptides has been revealed by mass spectrometry and appears to be based on a limited set of structural scaffolds. Genetic analysis has led to a further understanding of the molecular evolution mechanisms presiding over the generation of these combinatorial peptide libraries. Gene duplication and focal hypermutation, which has been described in cone snails, appear to be common mechanisms to venomous mollusks and spiders. Post-translational modifications, fine structural variations and new molecular scaffolds are other potential mechanisms of toxin diversification, leading to the pharmacologically complex cocktails used for predation and defense.
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Affiliation(s)
- Pierre Escoubas
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC) CNRS UMR 6097, 660 Route des Lucioles, Valbonne, France.
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Herrington J, Zhou YP, Bugianesi RM, Dulski PM, Feng Y, Warren VA, Smith MM, Kohler MG, Garsky VM, Sanchez M, Wagner M, Raphaelli K, Banerjee P, Ahaghotu C, Wunderler D, Priest BT, Mehl JT, Garcia ML, McManus OB, Kaczorowski GJ, Slaughter RS. Blockers of the delayed-rectifier potassium current in pancreatic beta-cells enhance glucose-dependent insulin secretion. Diabetes 2006; 55:1034-42. [PMID: 16567526 DOI: 10.2337/diabetes.55.04.06.db05-0788] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Delayed-rectifier K+ currents (I(DR)) in pancreatic beta-cells are thought to contribute to action potential repolarization and thereby modulate insulin secretion. The voltage-gated K+ channel, K(V)2.1, is expressed in beta-cells, and the biophysical characteristics of heterologously expressed channels are similar to those of I(DR) in rodent beta-cells. A novel peptidyl inhibitor of K(V)2.1/K(V)2.2 channels, guangxitoxin (GxTX)-1 (half-maximal concentration approximately 1 nmol/l), has been purified, characterized, and used to probe the contribution of these channels to beta-cell physiology. In mouse beta-cells, GxTX-1 inhibits 90% of I(DR) and, as for K(V)2.1, shifts the voltage dependence of channel activation to more depolarized potentials, a characteristic of gating-modifier peptides. GxTX-1 broadens the beta-cell action potential, enhances glucose-stimulated intracellular calcium oscillations, and enhances insulin secretion from mouse pancreatic islets in a glucose-dependent manner. These data point to a mechanism for specific enhancement of glucose-dependent insulin secretion by applying blockers of the beta-cell I(DR), which may provide advantages over currently used therapies for the treatment of type 2 diabetes.
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Affiliation(s)
- James Herrington
- Department of Ion Channels, Merck Research Laboratories, RY80N-C31, P.O. Box 2000, Rahway, NJ 07065-0900, USA.
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