1
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Cheng K, Lu J, Guo J, Wang R, Chen L, Wang X, Jiang Y, Li Y, Xu C, Kang Q, Qiaerxie G, Du P, Gao C, Yu Y, Yang Z, Wang W. Characterization of neutralizing chimeric heavy-chain antibodies against tetanus toxin. Hum Vaccin Immunother 2024; 20:2366641. [PMID: 38934499 PMCID: PMC11212558 DOI: 10.1080/21645515.2024.2366641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 06/07/2024] [Indexed: 06/28/2024] Open
Abstract
Tetanus toxin (TeNT) is one of the most toxic proteins. Neutralizing antibodies against TeNT are effective in prevention and treatment. In this study, 14 anti-tetanus nanobodies were obtained from a phage display nanobody library by immunizing a camel with the C-terminal receptor-binding domain of TeNT (TeNT-Hc) as the antigen. After fusion with the human Fc fragment, 11 chimeric heavy-chain antibodies demonstrated nanomolar binding toward TeNT-Hc. The results of toxin neutralization experiments showed that T83-7, T83-8, and T83-13 completely protected mice against 20 × the median lethal dose (LD50) at a low concentration. The neutralizing potency of T83-7, T83-8, and T83-13 against TeNT is 0.4 IU/mg, 0.4 IU/mg and 0.2 IU/mg, respectively. In the prophylactic setting, we found that 5 mg/kg of T83-13 provided the mice with full protection from tetanus, even when they were injected 14 days before exposure to 20 × LD50 TeNT. T83-7 and T83-8 were less effective, being fully protective only when challenged 7 or 10 days before exposure, respectively. In the therapeutic setting, 12 h after exposure to TeNT, 1 ~ 5 mg/kg of T83-7, and T83-8 could provide complete protection for mice against 5 × LD50 TeNT, while 1 mg/kg T83-13 could provide complete protection 24 h after exposure to 5 × LD50 TeNT. Our results suggested that these antibodies represent prophylactic and therapeutic activities against TeNT in a mouse model. The T83-7, T83-8, and T83-13 could form the basis for the subsequent development of drugs to treat TeNT toxicity.
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Affiliation(s)
- Kexuan Cheng
- Department of Occupational Health and Occupational Diseases, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Jiansheng Lu
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Jiazheng Guo
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Rong Wang
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Lei Chen
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Xi Wang
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Yujia Jiang
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Yating Li
- Department of Occupational Health and Occupational Diseases, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Changyan Xu
- Department of Occupational Health and Occupational Diseases, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Qinglin Kang
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Gulisaina Qiaerxie
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Peng Du
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Chen Gao
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Yunzhou Yu
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Zhixin Yang
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Wei Wang
- Department of Occupational Health and Occupational Diseases, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
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2
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Fabris F, Megighian A, Rossetto O, Simonato M, Schiavo G, Pirazzini M, Montecucco C. Local Tetanus Begins with a Neuromuscular Junction Paralysis around the Site of Tetanus Neurotoxin Release due to Cleavage of the Vesicle-Associated Membrane Protein. THE AMERICAN JOURNAL OF PATHOLOGY 2024; 194:1752-1763. [PMID: 38885925 DOI: 10.1016/j.ajpath.2024.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/14/2024] [Accepted: 05/23/2024] [Indexed: 06/20/2024]
Abstract
Local tetanus develops when limited amounts of tetanus neurotoxin (TeNT) are released by Clostridium tetani generated from spores inside a necrotic wound. Within days, a spastic paralysis restricted to the muscles of the affected anatomical area develops. This paralysis follows the retrograde transport of TeNT inside the axons of motoneurons and its uptake by inhibitory interneurons with cleavage of a vesicle-associated membrane protein required for neurotransmitter release. Consequently, incontrollable excitation of motoneurons causes contractures of innervated muscles and leads to local spastic paralysis. Here, the initial events occurring close to the site of TeNT release were investigated in a mouse model of local tetanus. A peripheral flaccid paralysis was found to occur, before or concurrent to the spastic paralysis. At variance from the confined TeNT proteolytic activity taking place within motor neuron terminals, central protein cleavage was detected within inhibitory interneurons controlling motor neuron efferents innervating muscle groups distant from the site of TeNT release. These results indicate peripheral activity of TeNT in tetanus and explains why the spastic paralysis observed in local tetanus, although confined to single limbs, generally affects multiple muscles. The initial TeNT neuroparalytic activity can be detected by measuring the compound muscle action potential, providing a very early diagnosis and therapy, thus preventing the ensuing life-threatening generalized tetanus.
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Affiliation(s)
- Federico Fabris
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Aram Megighian
- Department of Biomedical Sciences, University of Padua, Padua, Italy; Padua Neuroscience Center, University of Padua, Padua, Italy
| | - Ornella Rossetto
- Department of Biomedical Sciences, University of Padua, Padua, Italy; Center of Myology CIR-Myo, University of Padua, Padua, Italy; Institute of Neuroscience, National Research Council, Padua, Italy
| | - Morena Simonato
- Institute of Neuroscience, National Research Council, Padua, Italy
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, London, United Kingdom; UK Dementia Research Institute, University College London, London, United Kingdom
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padua, Padua, Italy; Center of Myology CIR-Myo, University of Padua, Padua, Italy.
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padua, Padua, Italy; Institute of Neuroscience, National Research Council, Padua, Italy.
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3
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Panzi C, Surana S, De La-Rocque S, Moretto E, Lazo OM, Schiavo G. Botulinum neurotoxin A modulates the axonal release of pathological tau in hippocampal neurons. Toxicon 2023; 228:107110. [PMID: 37037273 PMCID: PMC10636589 DOI: 10.1016/j.toxicon.2023.107110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/03/2023] [Accepted: 04/03/2023] [Indexed: 04/12/2023]
Abstract
Pathological tau aggregates propagate across functionally connected neuronal networks in human neurodegenerative pathologies, such as Alzheimer's disease. However, the mechanism underlying this process is poorly understood. Several studies have showed that tau release is dependent on neuronal activity and that pathological tau is found in the extracellular space in free form, as well as in the lumen of extracellular vesicles. We recently showed that metabotropic glutamate receptor activity and SNAP25 integrity modulate the release of pathological tau from human and mouse synaptosomes. Here, we have leveraged botulinum neurotoxins (BoNTs), which impair neurotransmitter release by cleaving specific synaptic SNARE proteins, to dissect molecular mechanisms related to tau release at synapses. In particular, we have tested the effect of botulinum neurotoxin A (BoNT/A) on the synaptic release of tau in primary mouse neurons. Hippocampal neurons were grown in microfluidic chambers and transduced with lentiviruses expressing human tau (hTau). We found that neuronal stimulation significantly increases the release of mutant hTau, whereas wild-type hTau is unaffected. Importantly, BoNT/A blocks mutant hTau release, indicating that this process is controlled by SNAP25, a component of the SNARE complex, in intact neurons. These results suggest that BoNTs are potent tools to study the spreading of pathological proteins in neurodegenerative diseases and could play a central role in identifying novel molecular targets for the development of therapeutic interventions to treat tauopathies.
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Affiliation(s)
- Chiara Panzi
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK; UK Dementia Research Institute, University College London, London, UK; UCL Queen Square Motor Neuron Disease Centre, University College London, London, UK.
| | - Sunaina Surana
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK; UK Dementia Research Institute, University College London, London, UK; UCL Queen Square Motor Neuron Disease Centre, University College London, London, UK
| | - Samantha De La-Rocque
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK; UK Dementia Research Institute, University College London, London, UK
| | - Edoardo Moretto
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK; UK Dementia Research Institute, University College London, London, UK; Institute of Neuroscience, CNR, 20854, Vedano al Lambro, Italy
| | - Oscar Marcelo Lazo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK; UK Dementia Research Institute, University College London, London, UK; UCL Queen Square Motor Neuron Disease Centre, University College London, London, UK
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK; UK Dementia Research Institute, University College London, London, UK; UCL Queen Square Motor Neuron Disease Centre, University College London, London, UK.
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4
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Manieri TM, Takata DY, Targino RC, Quintilio W, Batalha-Carvalho JV, da Silva CML, Moro AM. Characterization of Neutralizing Human Anti-Tetanus Monoclonal Antibodies Produced by Stable Cell Lines. Pharmaceutics 2022; 14:1985. [PMID: 36297421 PMCID: PMC9611486 DOI: 10.3390/pharmaceutics14101985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/14/2022] [Accepted: 09/16/2022] [Indexed: 10/12/2023] Open
Abstract
Tetanus toxin (TeNT) is produced by C. tetani, a spore-forming bacillus broadly spread in the environment. Although an inexpensive and safe vaccine is available, tetanus persists because of a lack of booster shots and variable responses to vaccines due to immunocompromised status or age-decreased immune surveillance. Tetanus is most prevalent in low- and medium-income countries, where it remains a health problem. Neutralizing monoclonal antibodies (mAbs) can prevent the severity of illness and death caused by C. tetani infection. We identified a panel of mAbs that bind to TeNT, some of which were investigated in a preclinical assay, showing that a trio of mAbs that bind to different sites of TeNT can neutralize the toxin and prevent symptoms and death in mice. We also identified two mAbs that can impair the binding of TeNT to the GT1b ganglioside receptor in neurons. In this work, to generate a series of cell lines, we constructed vectors containing sequences encoding heavy and light constant regions that can receive the paired variable regions resulting from PCRs of human B cells. In this way, we generated stable cell lines for five mAbs and compared and characterized the antibody produced in large quantities, enabling the characterization experiments. We present the results regarding the cell growth and viability in a fed-batch culture, titer measurement, and specific productivity estimation. The affinity of purified mAbs was analyzed by kinetics and under steady-state conditions, as three mAbs could not dissociate from TeNT within 36,000 s. The binding of mAbs to TeNT was confirmed by ELISA and inhibition of toxin binding to GT1b. The use of the mAbs mixture confirmed the individual mAb contribution to inhibition. We also analyzed the binding of mAbs to FcγR by surface plasmon resonance (SPR) and the glycan composition. Molecular docking analyses showed the binding site of an anti-tetanus mAb.
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Affiliation(s)
- Tania Maria Manieri
- Biopharmaceuticals Laboratory, Butantan Institute, Sao Paulo 05503-900, Brazil
| | - Daniela Yumi Takata
- Biopharmaceuticals Laboratory, Butantan Institute, Sao Paulo 05503-900, Brazil
- Interunits Graduate Program in Biotechnology, University of Sao Paulo, Sao Paulo 05508-270, Brazil
| | | | - Wagner Quintilio
- Biopharmaceuticals Laboratory, Butantan Institute, Sao Paulo 05503-900, Brazil
| | - João Victor Batalha-Carvalho
- Biopharmaceuticals Laboratory, Butantan Institute, Sao Paulo 05503-900, Brazil
- Graduate Program in Immunology, University of Sao Paulo, Sao Paulo 05508-270, Brazil
| | | | - Ana Maria Moro
- Biopharmaceuticals Laboratory, Butantan Institute, Sao Paulo 05503-900, Brazil
- Center for Research and Development in Immunobiologicals (CeRDI), Butantan Institute, Sao Paulo 05503-900, Brazil
- National Institute for Science and Technology (INCT/iii), University of Sao Paulo, Sao Paulo 05403-900, Brazil
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5
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Pirazzini M, Grinzato A, Corti D, Barbieri S, Leka O, Vallese F, Tonellato M, Silacci-Fregni C, Piccoli L, Kandiah E, Schiavo G, Zanotti G, Lanzavecchia A, Montecucco C. Exceptionally potent human monoclonal antibodies are effective for prophylaxis and treatment of tetanus in mice. J Clin Invest 2021; 131:151676. [PMID: 34618682 DOI: 10.1172/jci151676] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 09/28/2021] [Indexed: 01/15/2023] Open
Abstract
We used human monoclonal antibodies (humAbs) to study the mechanism of neuron intoxication by tetanus neurotoxin and to evaluate these antibodies as a safe preventive and therapeutic substitute for hyperimmune sera to treat tetanus in mice. By screening memory B cells from immune donors, we selected 2 tetanus neurotoxin-specific mAbs with exceptionally high neutralizing activities and extensively characterized them both structurally and functionally. We found that these antibodies interfered with the binding and translocation of the neurotoxin into neurons by interacting with 2 epitopes, whose identification pinpoints crucial events in the cellular pathogenesis of tetanus. Our observations explain the neutralization ability of these antibodies, which we found to be exceptionally potent in preventing experimental tetanus when injected into mice long before the toxin. Moreover, their Fab derivatives neutralized tetanus neurotoxin in post-exposure experiments, suggesting their potential for therapeutic use via intrathecal injection. As such, we believe these humAbs, as well as their Fab derivatives, meet the requirements to be considered for prophylactic and therapeutic use in human tetanus and are ready for clinical trials.
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Affiliation(s)
- Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | | | | | - Oneda Leka
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Francesca Vallese
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marika Tonellato
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Chiara Silacci-Fregni
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Luca Piccoli
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | | | - Giampietro Schiavo
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology and.,UK Dementia Research Institute, University College London, London, United Kingdom
| | - Giuseppe Zanotti
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Antonio Lanzavecchia
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland.,Fondazione Istituto Nazionale Genetica Molecolare, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico di Milano, Milano, Italy
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Institute of Neuroscience, National Research Council, Padova, Italy
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6
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Zanetti G, Mattarei A, Lista F, Rossetto O, Montecucco C, Pirazzini M. Novel Small Molecule Inhibitors That Prevent the Neuroparalysis of Tetanus Neurotoxin. Pharmaceuticals (Basel) 2021; 14:ph14111134. [PMID: 34832916 PMCID: PMC8618345 DOI: 10.3390/ph14111134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/25/2021] [Accepted: 11/04/2021] [Indexed: 01/22/2023] Open
Abstract
Tetanus neurotoxin (TeNT) is a protein exotoxin produced by Clostridium tetani that causes the deadly spastic neuroparalysis of tetanus. It consists of a metalloprotease light chain and of a heavy chain linked via a disulphide bond. TeNT binds to the neuromuscular junction (NMJ) and it is retro-axonally transported into vesicular compartments to the spinal cord, where it is released and taken up by inhibitory interneuron. Therein, the catalytic subunit is translocated into the cytoplasm where it cleaves its target protein VAMP-1/2 with consequent blockage of the release of inhibitory neurotransmitters. Vaccination with formaldehyde inactivated TeNT prevents the disease, but tetanus is still present in countries where vaccination coverage is partial. Here, we show that small molecule inhibitors interfering with TeNT trafficking or with the reduction of the interchain disulphide bond block the activity of the toxin in neuronal cultures and attenuate tetanus symptoms in vivo. These findings are relevant for the development of therapeutics against tetanus based on the inhibition of toxin molecules that are being retro-transported to or are already within the spinal cord and are, thus, not accessible to anti-TeNT immunoglobulins.
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Affiliation(s)
- Giulia Zanetti
- Department of Biomedical Sciences, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy; (G.Z.); (O.R.)
| | - Andrea Mattarei
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via F. Marzolo 5, 35131 Padova, Italy;
| | - Florigio Lista
- Scientific Department, Army Medical Center, Via Santo Stefano Rotondo 4, 00184 Rome, Italy;
| | - Ornella Rossetto
- Department of Biomedical Sciences, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy; (G.Z.); (O.R.)
- Italian Research Council, Institute of Neuroscience, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy
- CIR-Myo, Centro Interdipartimentale di Ricerca di Miologia, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy; (G.Z.); (O.R.)
- Italian Research Council, Institute of Neuroscience, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy
- Correspondence: (C.M.); (M.P.)
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy; (G.Z.); (O.R.)
- CIR-Myo, Centro Interdipartimentale di Ricerca di Miologia, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
- Correspondence: (C.M.); (M.P.)
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7
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Cai S, Kumar R, Singh BR. Clostridial Neurotoxins: Structure, Function and Implications to Other Bacterial Toxins. Microorganisms 2021; 9:2206. [PMID: 34835332 PMCID: PMC8618262 DOI: 10.3390/microorganisms9112206] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 01/20/2023] Open
Abstract
Gram-positive bacteria are ancient organisms. Many bacteria, including Gram-positive bacteria, produce toxins to manipulate the host, leading to various diseases. While the targets of Gram-positive bacterial toxins are diverse, many of those toxins use a similar mechanism to invade host cells and exert their functions. Clostridial neurotoxins produced by Clostridial tetani and Clostridial botulinum provide a classical example to illustrate the structure-function relationship of bacterial toxins. Here, we critically review the recent progress of the structure-function relationship of clostridial neurotoxins, including the diversity of the clostridial neurotoxins, the mode of actions, and the flexible structures required for the activation of toxins. The mechanism clostridial neurotoxins use for triggering their activity is shared with many other Gram-positive bacterial toxins, especially molten globule-type structures. This review also summarizes the implications of the molten globule-type flexible structures to other Gram-positive bacterial toxins. Understanding these highly dynamic flexible structures in solution and their role in the function of bacterial toxins not only fills in the missing link of the high-resolution structures from X-ray crystallography but also provides vital information for better designing antidotes against those toxins.
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Affiliation(s)
- Shuowei Cai
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, Dartmouth, MA 02747, USA
| | - Raj Kumar
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA; (R.K.); (B.R.S.)
| | - Bal Ram Singh
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA; (R.K.); (B.R.S.)
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8
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Cai CX, Schneck NA, Cozine T, Ivleva VB, Ragheb D, Gollapudi D, Patel A, Barefoot N, Gowetski DB, Lei QP. Investigation of Cysteine Modifications in Recombinant Protein Tetanus Toxoid Heavy Chain Fragment C. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1837-1840. [PMID: 34167299 PMCID: PMC9241332 DOI: 10.1021/jasms.1c00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
For conjugated HIV-1 fusion peptide vaccine development, recombinant Tetanus toxoid heavy chain fragment C (rTTHC) was applied as a carrier protein to boost peptide immunogenicity. Understanding the characteristics of rTTHC is the first step prior to the peptide conjugation. A comprehensive mass spectrometry (MS) characterization was performed on E. coli expressed rTTHC during its purification process. Intact mass along with peptide mapping analysis discovered the existence of three cysteine modification forms: glutathionylation, trisulfide bond modification, and disulfide bond shuffling, in correlation to a three-peak profile during a hydrophobic interaction chromatography (HIC) purification step. Coexistence of these multiple oxidative forms indicated that the active thiols underwent redox reaction in the rTTHC material. Identity confirmation of the rTTHC carrier protein by MS analysis provided pivotal guidance to assess the purification step and helped ensure that vaccine development could proceed.
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Affiliation(s)
- Cindy X Cai
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Nicole A Schneck
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Taryn Cozine
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Vera B Ivleva
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Daniel Ragheb
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Deepika Gollapudi
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Aakash Patel
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Nathan Barefoot
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Daniel B Gowetski
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Q Paula Lei
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
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9
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Megighian A, Pirazzini M, Fabris F, Rossetto O, Montecucco C. Tetanus and tetanus neurotoxin: From peripheral uptake to central nervous tissue targets. J Neurochem 2021; 158:1244-1253. [PMID: 33629408 DOI: 10.1111/jnc.15330] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/28/2021] [Accepted: 02/15/2021] [Indexed: 12/12/2022]
Abstract
Tetanus is a deadly but preventable disease caused by a protein neurotoxin produced by Clostridium tetani. Spores of C. tetani may contaminate a necrotic wound and germinate into a vegetative bacterium that releases a toxin, termed tetanus neurotoxin (TeNT). TeNT enters the general circulation, binds to peripheral motor neurons and sensory neurons, and is transported retroaxonally to the spinal cord. It then enters inhibitory interneurons and blocks the release of glycine or GABA causing a spastic paralysis. This review attempts to correlate the metalloprotease activity of TeNT and its trafficking and localization into the vertebrate body to the nature and sequence of appearance of the symptoms of tetanus.
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Affiliation(s)
- Aram Megighian
- Dipartimento di scienze Biomediche, Università di Padova, Padova, Italy.,Padova Neuroscience Center, Università di Padova, Padova, Italy
| | - Marco Pirazzini
- Dipartimento di scienze Biomediche, Università di Padova, Padova, Italy
| | - Federico Fabris
- Dipartimento di scienze Biomediche, Università di Padova, Padova, Italy
| | - Ornella Rossetto
- Dipartimento di scienze Biomediche, Università di Padova, Padova, Italy.,Istituto CNR di Neuroscienze, Università di Padova, Padova, Italy
| | - Cesare Montecucco
- Dipartimento di scienze Biomediche, Università di Padova, Padova, Italy.,Istituto CNR di Neuroscienze, Università di Padova, Padova, Italy
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10
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Zhang CM, Imoto Y, Hikima T, Inoue T. Structural flexibility of the tetanus neurotoxin revealed by crystallographic and solution scattering analyses. JOURNAL OF STRUCTURAL BIOLOGY-X 2021; 5:100045. [PMID: 33598655 PMCID: PMC7868712 DOI: 10.1016/j.yjsbx.2021.100045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Although the tetanus neurotoxin (TeNT) delivers its protease domain (LC) across the synaptic vesicle lumen into the cytosol via its receptor binding domain (HC) and translocation domain (HN), the molecular mechanism coordinating this membrane translocation remains unresolved. Here, we report the high-resolution crystal structures of full-length reduced TeNT (rTeNT, 2.3 Å), TeNT isolated HN (TeNT/iHN, 2.3 Å), TeNT isolated HC (TeNT/iHC, 1.5 Å), together with the solution structures of TeNT/iHN and beltless TeNT/iHN (TeNT/blHN). TeNT undergoes significant domains rotation of the HN and LC were demonstrated by structural comparison of rTeNT and non-reduced-TeNT (nrTeNT). A linker loop connects the HN and HC is essential for the self-domain rotation of TeNT. The TeNT-specific C869-C1093 disulfide bond is sensitive to the redox environment and its disruption provides linker loop flexibility, which enables domain arrangement of rTeNT distinct from that of nrTeNT. Furthermore, the mobility of C869 in the linker loop and the sensitivity to redox condition of C1093 were confirmed by crystal structure analysis of TeNT/iHC. On the other hand, the structural flexibility of HN was investigated by crystallographic and solution scattering analyses. It was found that the region (residues 698-769), which follows the translocation region had remarkable change in TeNT/iHN. Besides, the so-called belt region has a high propensity to swing around the upper half of TeNT/iHN at acidic pH. It provides the first overview of the dynamics of the Belt in solution. These newly obtained structural information that shed light on the transmembrane mechanism of TeNT.
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Affiliation(s)
- Chun-Ming Zhang
- Graduate School of Pharmaceutical Science, Osaka University, Suita, 565-0871 Osaka, Japan
| | - Yoshihiro Imoto
- Graduate School of Pharmaceutical Science, Osaka University, Suita, 565-0871 Osaka, Japan
| | - Takaaki Hikima
- Advanced Photon Technology Division, RIKEN SPring-8 Center, Sayo-gun, 679-6148, Japan
| | - Tsuyoshi Inoue
- Graduate School of Pharmaceutical Science, Osaka University, Suita, 565-0871 Osaka, Japan
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11
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Abstract
How protein toxins translocate their catalytic domain across a cell membrane is the least understood step in toxin action. This study utilized a reporter, β-lactamase, that was genetically fused to full-length, nontoxic tetanus toxin (βlac-TT) in discovery-based live-cell assays to study LC translocation. Directed mutagenesis identified a role for K768 in LC translocation. K768 was located between α15 and α16 (termed the cis-loop). Cellular assays showed that K768 did not interfere with other toxin functions, including cell binding, intracellular trafficking, and pore formation. The equivalent K768 is conserved among the clostridial neurotoxin family of proteins as a conserved structural motif. The cis-loop appears to contribute to LC translocation. The clostridial neurotoxins (CNTs) comprise tetanus toxin (TT) and botulinum neurotoxin (BoNT [BT]) serotypes (A to G and X) and several recently identified CNT-like proteins, including BT/En and the mosquito BoNT-like toxin Pmp1. CNTs are produced as single proteins cleaved to a light chain (LC) and a heavy chain (HC) connected by an interchain disulfide bond. LC is a zinc metalloprotease (cleaving soluble N-ethylmaleimide-sensitive factor attachment protein receptors [SNAREs]), while HC contains an N-terminal translocation domain (HCN) and a C-terminal receptor binding domain (HCC). HCN-mediated LC translocation is the least understood function of CNT action. Here, β-lactamase (βlac) was used as a reporter in discovery-based live-cell assays to characterize TT-mediated LC translocation. Directed mutagenesis identified a role for a charged loop (767DKE769) connecting α15 and α16 (cis-loop) within HCN in LC translocation; aliphatic substitution inhibited LC translocation but not other toxin functions such as cell binding, intracellular trafficking, or HCN-mediated pore formation. K768 was conserved among the CNTs. In molecular simulations of the HCN with a membrane, the cis-loop did not bind with the cell membrane. Taken together, the results of these studies implicate the cis-loop in LC translocation, independently of pore formation. IMPORTANCE How protein toxins translocate their catalytic domain across a cell membrane is the least understood step in toxin action. This study utilized a reporter, β-lactamase, that was genetically fused to full-length, nontoxic tetanus toxin (βlac-TT) in discovery-based live-cell assays to study LC translocation. Directed mutagenesis identified a role for K768 in LC translocation. K768 was located between α15 and α16 (termed the cis-loop). Cellular assays showed that K768 did not interfere with other toxin functions, including cell binding, intracellular trafficking, and pore formation. The equivalent K768 is conserved among the clostridial neurotoxin family of proteins as a conserved structural motif. The cis-loop appears to contribute to LC translocation.
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Steward L, Brin MF, Brideau-Andersen A. Novel Native and Engineered Botulinum Neurotoxins. Handb Exp Pharmacol 2020; 263:63-89. [PMID: 32274579 DOI: 10.1007/164_2020_351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Botulinum neurotoxins (BoNTs), produced by Clostridia and other bacteria, are the most potent toxins known. Their cleavage of the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) proteins in neurons prevents the release of neurotransmitters, thus resulting in the muscle paralysis that is characteristic of botulism. This mechanism of action has been exploited for a variety of therapeutic and cosmetic applications of BoNTs. This chapter provides an overview of the native BoNTs, including the classical serotypes and their clinical use, mosaic BoNTs, and novel BoNTs that have been recently identified in clostridial and non-clostridial strains. In addition, the modular structure of native BoNTs, which are composed of a light chain and a heavy chain, is amenable to a multitude of novel fusions and mutations using molecular biology techniques. These novel recombinant BoNTs have been used or are being developed to further characterize the biology of toxins, to assist in vaccine production, to serve as delivery vehicles to neurons, and to be utilized as novel therapeutics for both neuronal and non-neuronal cells.
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Affiliation(s)
| | - Mitchell F Brin
- Allergan plc, Irvine, CA, USA.,University of California, Irvine, CA, USA
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13
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Rossetto O, Pirazzini M, Lista F, Montecucco C. The role of the single interchains disulfide bond in tetanus and botulinum neurotoxins and the development of antitetanus and antibotulism drugs. Cell Microbiol 2019; 21:e13037. [PMID: 31050145 PMCID: PMC6899712 DOI: 10.1111/cmi.13037] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/18/2019] [Accepted: 04/30/2019] [Indexed: 01/02/2023]
Abstract
A large number of bacterial toxins consist of active and cell binding protomers linked by an interchain disulfide bridge. The largest family of such disulfide-bridged exotoxins is that of the clostridial neurotoxins that consist of two chains and comprise the tetanus neurotoxins causing tetanus and the botulinum neurotoxins causing botulism. Reduction of the interchain disulfide abolishes toxicity, and we discuss the experiments that revealed the role of this structural element in neuronal intoxication. The redox couple thioredoxin reductase-thioredoxin (TrxR-Trx) was identified as the responsible for reduction of this disulfide occurring on the cytosolic surface of synaptic vesicles. We then discuss the very relevant finding that drugs that inhibit TrxR-Trx also prevent botulism. On this basis, we propose that ebselen and PX-12, two TrxR-Trx specific drugs previously used in clinical trials in humans, satisfy all the requirements for clinical tests aiming at evaluating their capacity to effectively counteract human and animal botulism arising from intestinal toxaemias such as infant botulism.
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Affiliation(s)
- Ornella Rossetto
- Dipartimento di Scienze BiomedicheUniversità di PadovaPaduaItaly
| | - Marco Pirazzini
- Dipartimento di Scienze BiomedicheUniversità di PadovaPaduaItaly
| | - Florigio Lista
- Sezione di Istologia e Biologia MolecolareCentro di ricerca Medica e Veterinaria del Ministero della DifesaRomeItaly
| | - Cesare Montecucco
- Dipartimento di Scienze BiomedicheUniversità di PadovaPaduaItaly
- Istituto Neuroscienze del CNRUniversità di PadovaPaduaItaly
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14
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Pereira C, Rodrigues IS, Pereira LMG, Lisboa J, Pinto RD, Araújo L, Oliveira P, Benz R, Dos Santos NMS, do Vale A. Role of AIP56 disulphide bond and its reduction by cytosolic redox systems for efficient intoxication. Cell Microbiol 2019; 22:e13109. [PMID: 31454143 DOI: 10.1111/cmi.13109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/08/2019] [Accepted: 08/21/2019] [Indexed: 12/14/2022]
Abstract
Apoptosis-inducing protein of 56 kDa (AIP56) is a major virulence factor of Photobacterium damselae subsp. piscicida, a gram-negative pathogen that infects warm water fish species worldwide and causes serious economic losses in aquacultures. AIP56 is a single-chain AB toxin composed by two domains connected by an unstructured linker peptide flanked by two cysteine residues that form a disulphide bond. The A domain comprises a zinc-metalloprotease moiety that cleaves the NF-kB p65, and the B domain is involved in binding and internalisation of the toxin into susceptible cells. Previous experiments suggested that disruption of AIP56 disulphide bond partially compromised toxicity, but conclusive evidences supporting the importance of that bond in intoxication were lacking. Here, we show that although the disulphide bond of AIP56 is dispensable for receptor recognition, endocytosis, and membrane interaction, it needs to be intact for efficient translocation of the toxin into the cytosol. We also show that the host cell thioredoxin reductase-thioredoxin system is involved in AIP56 intoxication by reducing the disulphide bond of the toxin at the cytosol. The present study contributes to a better understanding of the molecular mechanisms operating during AIP56 intoxication and reveals common features shared with other AB toxins.
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Affiliation(s)
- Cassilda Pereira
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Inês S Rodrigues
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Liliana M G Pereira
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Johnny Lisboa
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Rute D Pinto
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Leonor Araújo
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Pedro Oliveira
- EPIUnit, ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Roland Benz
- Department of Life Sciences and Chemistry, Jacobs University, Bremen, Germany
| | - Nuno M S Dos Santos
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Ana do Vale
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
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15
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Brenner N, Butt J, Bomfim IL, Tabatabai J, Pawlita M, Schnitzler P, Waterboer T. Validation of monoplex assays detecting antibodies against Corynebacterium diphtheriae and Clostridium tetani toxins, rubella virus and parvovirus B19 for incorporation into Multiplex Serology. Methods 2019; 158:44-53. [PMID: 30703462 DOI: 10.1016/j.ymeth.2019.01.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/27/2018] [Accepted: 01/23/2019] [Indexed: 01/12/2023] Open
Abstract
Serological assays detecting antibodies in serum or plasma samples are useful and versatile instruments to investigate an individual's infection and vaccination history, e.g. for clinical diagnosis, personal risk evaluation, and seroepidemiological studies. Multiplex Serology is a suspension bead array-based high-throughput methodology for simultaneous measurement of antibodies against multiple pathogens in a single reaction vessel, thus economizing sample volume, measurement time, and costs. We developed and validated bead-based pathogen-specific Monoplex Serology assays, i.e. assays including only antigens for the respective pathogen, to detect antibodies against Corynebacterium diphtheriae and Clostridium tetani toxins, rubella virus and parvovirus B19. The developed assays expand the portfolio of existing pathogen-specific bead-based serology assays and can be efficiently incorporated into larger Multiplex Serology panels. The newly developed Monoplex Serology assays consist of only one antigen per infectious agent, expressed as Glutathione S-transferase-fusion proteins in E. coli. Specificity, sensitivity and Cohen's kappa statistics in comparison with routine clinical diagnostic assays were calculated for serum dilutions 1:100 and 1:1000. All pathogen-specific assays were successfully validated at both serum dilutions with the exception of rubella Monoplex Serology which showed impaired sensitivity (57.6%) at dilution 1:1000. Specificities of successfully validated Monoplex Serology assays ranged from 85.6% to 100.0% (median: 91.7%), and sensitivities from 81.3% to 95.8% (median: 90.9%); agreement with the reference assays ranged from substantial to almost perfect (kappa: 0.66-0.86, median: 0.78). Statistical performance and slim assay design enable efficient incorporation of the developed assays into Multiplex Serology.
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Affiliation(s)
- Nicole Brenner
- Infections and Cancer Epidemiology, German Cancer Research Center, Heidelberg, Germany; Faculty of Biosciences, Heidelberg University, Heidelberg, Germany.
| | - Julia Butt
- Infections and Cancer Epidemiology, German Cancer Research Center, Heidelberg, Germany.
| | - Izaura Lima Bomfim
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
| | - Julia Tabatabai
- Center for Infectious Diseases, Virology, University Hospital of Heidelberg, Heidelberg, Germany.
| | - Michael Pawlita
- Infections and Cancer Epidemiology, German Cancer Research Center, Heidelberg, Germany.
| | - Paul Schnitzler
- Center for Infectious Diseases, Virology, University Hospital of Heidelberg, Heidelberg, Germany.
| | - Tim Waterboer
- Infections and Cancer Epidemiology, German Cancer Research Center, Heidelberg, Germany.
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16
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Surana S, Tosolini AP, Meyer IF, Fellows AD, Novoselov SS, Schiavo G. The travel diaries of tetanus and botulinum neurotoxins. Toxicon 2018; 147:58-67. [DOI: 10.1016/j.toxicon.2017.10.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/09/2017] [Accepted: 10/11/2017] [Indexed: 10/18/2022]
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17
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Zuverink M, Barbieri JT. Protein Toxins That Utilize Gangliosides as Host Receptors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 156:325-354. [PMID: 29747819 DOI: 10.1016/bs.pmbts.2017.11.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Subsets of protein toxins utilize gangliosides as host receptors. Gangliosides are preferred receptors due to their extracellular localization on the eukaryotic cell and due to their essential nature in host physiology. Glycosphingolipids, including gangliosides, are mediators of signal transduction within and between eukaryotic cells. Protein toxins possess AB structure-function organization, where the A domain encodes a catalytic function for the posttranslational modification of a host macromolecule, including proteins and nucleic acids, and a B domain, which encodes host receptor recognition, including proteins and glycosphingolipids, alone or in combination. Protein toxins use similar strategies to bind glycans by pockets and loops, generally employing hydrogen bonding and aromatic stacking to stabilize interactions with sugars. In some cases, glycan binding facilitates uptake, while in other cases, cross-linking or a second receptor is necessary to stimulate entry. The affinity that protein toxins have for host glycans is necessary for tissue targeting, but not always sufficient to cause disease. In addition to affinity for binding the glycan, the lipid moiety also plays an important role in productive uptake and tissue tropism. Upon endocytosis, the protein toxin must escape to another intracellular compartment or into cytosol to modify a host substrate, modulating host signaling, often resulting in cytotoxic or apoptotic events in the cell, and a unique morbidity for the organism. The study of protein toxins that utilize gangliosides as host receptors has illuminated numerous eukaryotic cellular processes, identified the basis for developing interventions to prevent disease through vaccines and control bacterial diseases through therapies. In addition, subsets of these protein toxins have been utilized as therapeutic agents to treat numerous human inflictions.
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18
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Protein Structure Facilitates High-Resolution Immunological Mapping. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00275-17. [PMID: 29046310 DOI: 10.1128/cvi.00275-17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Select agents (SA) pose unique challenges for licensing vaccines and therapies. In the case of toxin-mediated diseases, HHS assigns guidelines for SA use, oversees vaccine and therapy development, and approves animal models and approaches to identify mechanisms for toxin neutralization. In this commentary, we discuss next-generation vaccines and therapies against ricin toxin and botulinum toxin, which are regulated SA toxins that utilize structure-based approaches for countermeasures to guide rapid response to future biothreats.
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Pirazzini M, Azarnia Tehran D, Zanetti G, Rossetto O, Montecucco C. Hsp90 and Thioredoxin-Thioredoxin Reductase enable the catalytic activity of Clostridial neurotoxins inside nerve terminals. Toxicon 2017; 147:32-37. [PMID: 29111118 DOI: 10.1016/j.toxicon.2017.10.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/21/2017] [Accepted: 10/23/2017] [Indexed: 12/12/2022]
Abstract
Botulinum (BoNTs) and tetanus (TeNT) neurotoxins are the most toxic substances known and form the growing family of Clostridial neurotoxins (CNT), the etiologic agents of botulism and tetanus. CNT are composed of a metalloprotease light chain (L), linked via a disulfide bond to a heavy chain (H). H mediates the binding to nerve terminals and the membrane translocation of L into the cytosol, where its substrates, the three SNARE proteins, are localized. L translocation is accompanied by unfolding and, once delivered on the cytosolic side of the endosome membrane, it has to be reduced and reacquire the native fold to be active. The Thioredoxin-Thioredoxin Reductase system (Trx-TrxR) specifically reduces the interchain disulfide bond while the cytosolic chaperone protein Hsp90 mediates L refolding. Both steps are essential for CNT activity and their inhibition efficiently blocks the neurotoxicity in cultured neurons and mice. Trx and its reductase physically interact with Hsp90 and are loosely bound to the cytosolic side of synaptic vesicles, the organelle exploited by CNT to enter nerve terminals and wherefrom L is translocated into the cytosol. Therefore, Trx, TrxR and Hsp90 orchestrate a chaperone-redox molecular machinery that enables the catalytic activity of the L inside nerve terminals. Given the fundamental role of L reduction and refolding, this machinery represents a rational target for the development of mechanism-based antitoxins.
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Affiliation(s)
- Marco Pirazzini
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
| | - Domenico Azarnia Tehran
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Giulia Zanetti
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Ornella Rossetto
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy; Istituto CNR di Neuroscienze, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
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20
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Masuyer G, Conrad J, Stenmark P. The structure of the tetanus toxin reveals pH-mediated domain dynamics. EMBO Rep 2017; 18:1306-1317. [PMID: 28645943 PMCID: PMC5538627 DOI: 10.15252/embr.201744198] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 05/16/2017] [Accepted: 05/23/2017] [Indexed: 11/09/2022] Open
Abstract
The tetanus neurotoxin (TeNT) is a highly potent toxin produced by Clostridium tetani that inhibits neurotransmission of inhibitory interneurons, causing spastic paralysis in the tetanus disease. TeNT differs from the other clostridial neurotoxins by its unique ability to target the central nervous system by retrograde axonal transport. The crystal structure of the tetanus toxin reveals a "closed" domain arrangement stabilised by two disulphide bridges, and the molecular details of the toxin's interaction with its polysaccharide receptor. An integrative analysis combining X-ray crystallography, solution scattering and single particle electron cryo-microscopy reveals pH-mediated domain rearrangements that may give TeNT the ability to adapt to the multiple environments encountered during intoxication, and facilitate binding to distinct receptors.
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Affiliation(s)
- Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Julian Conrad
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
- Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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21
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Pirazzini M, Rossetto O, Eleopra R, Montecucco C. Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology. Pharmacol Rev 2017; 69:200-235. [PMID: 28356439 PMCID: PMC5394922 DOI: 10.1124/pr.116.012658] [Citation(s) in RCA: 410] [Impact Index Per Article: 58.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The study of botulinum neurotoxins (BoNT) is rapidly progressing in many aspects.
Novel BoNTs are being discovered owing to next generation sequencing, but their
biologic and pharmacological properties remain largely unknown. The molecular
structure of the large protein complexes that the toxin forms with accessory
proteins, which are included in some BoNT type A1 and B1 pharmacological
preparations, have been determined. By far the largest effort has been dedicated to
the testing and validation of BoNTs as therapeutic agents in an ever increasing
number of applications, including pain therapy. BoNT type A1 has been also exploited
in a variety of cosmetic treatments, alone or in combination with other agents, and
this specific market has reached the size of the one dedicated to the treatment of
medical syndromes. The pharmacological properties and mode of action of BoNTs have
shed light on general principles of neuronal transport and protein-protein
interactions and are stimulating basic science studies. Moreover, the wide array of
BoNTs discovered and to be discovered and the production of recombinant BoNTs endowed
with specific properties suggest novel uses in therapeutics with increasing
disease/symptom specifity. These recent developments are reviewed here to provide an
updated picture of the biologic mechanism of action of BoNTs, of their increasing use
in pharmacology and in cosmetics, and of their toxicology.
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Affiliation(s)
- Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Italy (M.P., O.R., C.M.); Neurologic Department, University-Hospital S. Maria della Misericordia, Udine, Italy (R.E.); and Consiglio Nazionale delle Ricerche, Institute of Neuroscience, University of Padova, Italy (C.M.)
| | - Ornella Rossetto
- Department of Biomedical Sciences, University of Padova, Italy (M.P., O.R., C.M.); Neurologic Department, University-Hospital S. Maria della Misericordia, Udine, Italy (R.E.); and Consiglio Nazionale delle Ricerche, Institute of Neuroscience, University of Padova, Italy (C.M.)
| | - Roberto Eleopra
- Department of Biomedical Sciences, University of Padova, Italy (M.P., O.R., C.M.); Neurologic Department, University-Hospital S. Maria della Misericordia, Udine, Italy (R.E.); and Consiglio Nazionale delle Ricerche, Institute of Neuroscience, University of Padova, Italy (C.M.)
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Italy (M.P., O.R., C.M.); Neurologic Department, University-Hospital S. Maria della Misericordia, Udine, Italy (R.E.); and Consiglio Nazionale delle Ricerche, Institute of Neuroscience, University of Padova, Italy (C.M.)
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22
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Brgles M, Prebeg P, Kurtović T, Ranić J, Marchetti-Deschmann M, Allmaier G, Halassy B. Optimization of tetanus toxoid ammonium sulfate precipitation process using response surface methodology. Prep Biochem Biotechnol 2017; 46:695-703. [PMID: 26760928 DOI: 10.1080/10826068.2015.1135452] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Tetanus toxoid (TTd) is a highly immunogenic, detoxified form of tetanus toxin, a causative agent of tetanus disease, produced by Clostridium tetani. Since tetanus disease cannot be eradicated but is easily prevented by vaccination, the need for the tetanus vaccine is permanent. The aim of this work was to investigate the possibility of optimizing TTd purification, i.e., ammonium sulfate precipitation process. The influence of the percentage of ammonium sulfate, starting amount of TTd, buffer type, pH, temperature, and starting purity of TTd on the purification process were investigated using optimal design for response surface models. Responses measured for evaluation of the ammonium sulfate precipitation process were TTd amount (Lf/mL) and total protein content. These two parameters were used to calculate purity (Lf/mgPN) and the yield of the process. Results indicate that citrate buffer, lower temperature, and lower starting amount of TTd result in higher purities of precipitates. Gel electrophoresis combined with matrix-assisted laser desorption ionization-mass spectrometric analysis of precipitates revealed that there are no inter-protein cross-links and that all contaminating proteins have pIs similar to TTd, so this is most probably the reason for the limited success of purification by precipitation.
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Affiliation(s)
- Marija Brgles
- a Centre for Research and Knowledge Transfer , University of Zagreb , Zagreb , Croatia
| | - Pero Prebeg
- b Faculty of Mechanical Engineering and Naval Architecture , University of Zagreb , Zagreb , Croatia
| | - Tihana Kurtović
- a Centre for Research and Knowledge Transfer , University of Zagreb , Zagreb , Croatia
| | - Jelena Ranić
- c Bacterial Vaccine Department, Institute of Immunology , Zagreb , Croatia
| | | | - Günter Allmaier
- d Institute of Chemical Technologies and Analytics , Technische Universität Wien , Vienna , Austria
| | - Beata Halassy
- a Centre for Research and Knowledge Transfer , University of Zagreb , Zagreb , Croatia
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Tetanus Neurotoxin Neutralizing Antibodies Screened from a Human Immune scFv Antibody Phage Display Library. Toxins (Basel) 2016; 8:toxins8090266. [PMID: 27626445 PMCID: PMC5037492 DOI: 10.3390/toxins8090266] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 12/31/2022] Open
Abstract
Tetanus neurotoxin (TeNT) produced by Clostridiumtetani is one of the most poisonous protein substances. Neutralizing antibodies against TeNT can effectively prevent and cure toxicosis. Using purified Hc fragments of TeNT (TeNT-Hc) as an antigen, three specific neutralizing antibody clones recognizing different epitopes were selected from a human immune scFv antibody phage display library. The three antibodies (2-7G, 2-2D, and S-4-7H) can effectively inhibit the binding between TeNT-Hc and differentiated PC-12 cells in vitro. Moreover, 2-7G inhibited TeNT-Hc binding to the receptor via carbohydrate-binding sites of the W pocket while 2-2D and S-4-7H inhibited binding of the R pocket. Although no single mAb completely protected mice from the toxin, they could both prolong survival when challenged with 20 LD50s (50% of the lethal dose) of TeNT. When used together, the mAbs completely neutralized 1000 LD50s/mg Ab, indicating their high neutralizing potency in vivo. Antibodies recognizing different carbohydrate-binding pockets could have higher synergistic toxin neutralization activities than those that recognize the same pockets. These results could lead to further production of neutralizing antibody drugs against TeNT and indicate that using TeNT-Hc as an antigen for screening human antibodies for TeNT intoxication therapy from human immune antibody library was convenient and effective.
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Zuverink M, Barbieri JT. From GFP to β-lactamase: advancing intact cell imaging for toxins and effectors. Pathog Dis 2015; 73:ftv097. [PMID: 26500183 DOI: 10.1093/femspd/ftv097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 11/13/2022] Open
Abstract
Canonical reporters such as green fluorescent protein (GFP) and luciferase have assisted researchers in probing cellular pathways and processes. Prior research in pathogenesis depended on sensitivity of biochemical and biophysical techniques to identify effectors and elucidate entry mechanisms. Recently, the β-lactamase (βlac) reporter system has advanced toxin and effector reporting by permitting measurement of βlac delivery into the cytosol or host βlac expression in intact cells. βlac measurement in cells was facilitated by the development of the fluorogenic substrate, CCF2-AM, to identify novel effectors, target cells, and domains involved in bacterial pathogenesis. The assay is also adaptable for high-throughput screening of small molecule inhibitors against toxins, providing information on mechanism and potential therapeutic agents. The versatility and limitations of the βlac reporter system as applied to toxins and effectors are discussed in this review.
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Affiliation(s)
- Madison Zuverink
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI 53226, USA
| | - Joseph T Barbieri
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI 53226, USA
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Zanetti G, Azarnia Tehran D, Pirazzini M, Binz T, Shone CC, Fillo S, Lista F, Rossetto O, Montecucco C. Inhibition of botulinum neurotoxins interchain disulfide bond reduction prevents the peripheral neuroparalysis of botulism. Biochem Pharmacol 2015; 98:522-30. [PMID: 26449594 DOI: 10.1016/j.bcp.2015.09.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 09/29/2015] [Indexed: 12/18/2022]
Abstract
Botulinum neurotoxins (BoNTs) form a growing family of metalloproteases with a unique specificity either for VAMP, SNAP25 or syntaxin. The BoNTs are grouped in seven different serotypes indicated by letters from A to G. These neurotoxins enter the cytosol of nerve terminals via a 100 kDa chain which binds to the presynaptic membrane and assists the translocation of a 50 kDa metalloprotease chain. These two chains are linked by a single disulfide bridge which plays an essential role during the entry of the metalloprotease chain in the cytosol, but thereafter it has to be reduced to free the proteolytic activity. Its reduction is mediated by thioredoxin which is continuously regenerated by its reductase. Here we show that inhibitors of thioredoxin reductase or of thioredoxin prevent the specific proteolysis of VAMP by the four VAMP-specific BoNTs: type B, D, F and G. These compounds are effective not only in primary cultures of neurons, but also in preventing the in vivo mouse limb neuroparalysis. In addition, one of these inhibitors, Ebselen, largely protects mice from the death caused by a systemic injection. Together with recent results obtained with BoNTs specific for SNAP25 and syntaxin, the present data demonstrate the essential role of the thioredoxin-thioredoxin reductase system in reducing the interchain disulfide during the nerve intoxication mechanism of all serotypes. Therefore its inhibitors should be considered for a possible use to prevent botulism and for treating infant botulism.
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Affiliation(s)
- Giulia Zanetti
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Domenico Azarnia Tehran
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Marcon Pirazzini
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Thomas Binz
- Institut für Biochemie, OE 4310, Medizinische Hochschule Hannover, 30623 Hannover, Germany
| | - Clifford C Shone
- Public Health England, Porton Down, Salisbury, Wiltshire SP4 OJG, UK
| | - Silvia Fillo
- Histology and Molecular Biology Section, Army Medical and Veterinary Research Center, Via Santo Stefano Rotondo 4, 00184 Rome, Italy
| | - Florigio Lista
- Histology and Molecular Biology Section, Army Medical and Veterinary Research Center, Via Santo Stefano Rotondo 4, 00184 Rome, Italy
| | - Ornella Rossetto
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy; Istituto CNR di Neuroscienze, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
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On the translocation of botulinum and tetanus neurotoxins across the membrane of acidic intracellular compartments. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:467-74. [PMID: 26307528 DOI: 10.1016/j.bbamem.2015.08.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 08/04/2015] [Accepted: 08/17/2015] [Indexed: 01/25/2023]
Abstract
Tetanus and botulinum neurotoxins are produced by anaerobic bacteria of the genus Clostridium and are the most poisonous toxins known, with 50% mouse lethal dose comprised within the range of 0.1-few nanograms per Kg, depending on the individual toxin. Botulinum neurotoxins are similarly toxic to humans and can therefore be considered for potential use in bioterrorism. At the same time, their neurospecificity and reversibility of action make them excellent therapeutics for a growing and heterogeneous number of human diseases that are characterized by a hyperactivity of peripheral nerve terminals. The complete crystallographic structure is available for some botulinum toxins, and reveals that they consist of four domains functionally related to the four steps of their mechanism of neuron intoxication: 1) binding to specific receptors of the presynaptic membrane; 2) internalization via endocytic vesicles; 3) translocation across the membrane of endocytic vesicles into the neuronal cytosol; 4) catalytic activity of the enzymatic moiety directed towards the SNARE proteins. Despite the many advances in understanding the structure-mechanism relationship of tetanus and botulinum neurotoxins, the molecular events involved in the translocation step have been only partially elucidated. Here we will review recent advances that have provided relevant insights on the process and discuss possible models that can be experimentally tested. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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27
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Pirazzini M, Azarnia Tehran D, Zanetti G, Lista F, Binz T, Shone CC, Rossetto O, Montecucco C. The thioredoxin reductase--Thioredoxin redox system cleaves the interchain disulphide bond of botulinum neurotoxins on the cytosolic surface of synaptic vesicles. Toxicon 2015; 107:32-6. [PMID: 26130523 DOI: 10.1016/j.toxicon.2015.06.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 06/23/2015] [Indexed: 11/16/2022]
Abstract
Botulinum neurotoxins (BoNTs) are Janus toxins, as they are at the same time the most deadly substances known and one of the safest drugs used in human therapy. They specifically block neurotransmission at peripheral nerves through the proteolysis of SNARE proteins, i.e. the essential proteins which are the core of the neuroexocytosis machinery. Even if BoNTs are traditionally known as seven main serotypes, their actual number is much higher as each serotype exists in many different subtypes, with individual biological properties and little antigenic relations. Since BoNTs can be used as biological weapons, and the only currently available therapy is based on immunological approaches, the existence of so many different subtypes is a major safety problem. Nevertheless, all BoNT isoforms are structurally similar and intoxicate peripheral nerve endings via a conserved mechanism. They consist of two chains linked by a unique disulphide bond which must be reduced to enable their toxicity. We found that thioredoxin 1 and its reductase compose the cell redox system responsible for this reduction, and its inhibition via specific chemicals significantly reduces BoNTs activity, in vitro as well as in vivo. Such molecules can be considered as lead compounds for the development of pan-inhibitors.
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Affiliation(s)
- Marco Pirazzini
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
| | - Domenico Azarnia Tehran
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Giulia Zanetti
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Florigio Lista
- Histology and Molecular Biology Section, Army Medical and Veterinary Research Center, Via Santo Stefano Rotondo 4, 00184 Rome, Italy
| | - Thomas Binz
- Institut fur Biochemie, Medizinische Hochschule Hannover, 30623 Hannover, Germany
| | - Clifford C Shone
- Public Health England, Porton Down, Salisbury, Wiltshire, SP4 OJG, UK
| | - Ornella Rossetto
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy; Istituto CNR di Neuroscienze, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
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28
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Farrow B, Wong M, Malette J, Lai B, Deyle KM, Das S, Nag A, Agnew HD, Heath JR. Epitope Targeting of Tertiary Protein Structure Enables Target-Guided Synthesis of a Potent In-Cell Inhibitor of Botulinum Neurotoxin. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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29
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Farrow B, Wong M, Malette J, Lai B, Deyle KM, Das S, Nag A, Agnew HD, Heath JR. Epitope targeting of tertiary protein structure enables target-guided synthesis of a potent in-cell inhibitor of botulinum neurotoxin. Angew Chem Int Ed Engl 2015; 54:7114-9. [PMID: 25925721 DOI: 10.1002/anie.201502451] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/09/2015] [Indexed: 12/14/2022]
Abstract
Botulinum neurotoxin (BoNT) serotype A is the most lethal known toxin and has an occluded structure, which prevents direct inhibition of its active site before it enters the cytosol. Target-guided synthesis by in situ click chemistry is combined with synthetic epitope targeting to exploit the tertiary structure of the BoNT protein as a landscape for assembling a competitive inhibitor. A substrate-mimicking peptide macrocycle is used as a direct inhibitor of BoNT. An epitope-targeting in situ click screen is utilized to identify a second peptide macrocycle ligand that binds to an epitope that, in the folded BoNT structure, is active-site-adjacent. A second in situ click screen identifies a molecular bridge between the two macrocycles. The resulting divalent inhibitor exhibits an in vitro inhibition constant of 165 pM against the BoNT/A catalytic chain. The inhibitor is carried into cells by the intact holotoxin, and demonstrates protection and rescue of BoNT intoxication in a human neuron model.
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Affiliation(s)
- Blake Farrow
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 (USA).,Department of Applied Physics and Materials Science, California Institute of Technology (USA)
| | - Michelle Wong
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 (USA)
| | - Jacquie Malette
- Indi Molecular, 6162 Bristol Parkway, Culver City, CA 90230 (USA)
| | - Bert Lai
- Indi Molecular, 6162 Bristol Parkway, Culver City, CA 90230 (USA)
| | - Kaycie M Deyle
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 (USA)
| | - Samir Das
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 (USA)
| | - Arundhati Nag
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 (USA)
| | - Heather D Agnew
- Indi Molecular, 6162 Bristol Parkway, Culver City, CA 90230 (USA)
| | - James R Heath
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 (USA).
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A Heterologous Reporter Defines the Role of the Tetanus Toxin Interchain Disulfide in Light-Chain Translocation. Infect Immun 2015; 83:2714-24. [PMID: 25895970 DOI: 10.1128/iai.00477-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 04/13/2015] [Indexed: 11/20/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) and tetanus toxin (TeNT) are the most potent toxins for humans and elicit unique pathologies due to their ability to traffic within motor neurons. BoNTs act locally within motor neurons to elicit flaccid paralysis, while retrograde TeNT traffics to inhibitory neurons within the central nervous system (CNS) to elicit spastic paralysis. BoNT and TeNT are dichain proteins linked by an interchain disulfide bond comprised of an N-terminal catalytic light chain (LC) and a C-terminal heavy chain (HC) that encodes an LC translocation domain (HCT) and a receptor-binding domain (HCR). LC translocation is the least understood property of toxin action, but it involves low pH, proteolysis, and an intact interchain disulfide bridge. Recently, Pirazzini et al. (FEBS Lett 587:150-155, 2013, http://dx.doi.org/10.1016/j.febslet.2012.11.007) observed that inhibitors of thioredoxin reductase (TrxR) blocked TeNT and BoNT action in cerebellar granular neurons. In the current study, an atoxic TeNT LC translocation reporter was engineered by fusing β-lactamase to the N terminus of TeNT [βlac-TeNT(RY)] to investigate LC translocation in primary cortical neurons and Neuro-2a cells. βlac-TeNT(RY) retained the interchain disulfide bond, showed ganglioside-dependent binding to neurons, required acidification to promote βlac translocation, and was sensitive to auranofin, an inhibitor of thioredoxin reductase. Mutation of βlac-TeNT(RY) at C439S and C467S eliminated the interchain disulfide bond and inhibited βlac translocation. These data support the requirement of an intact interchain disulfide for LC translocation and imply that disulfide reduction is a prerequisite for LC delivery into the host cytosol. The data also support a model that LC translocation proceeds from the C to the N terminus. βlac-TeNT(RY) is the first reporter system to measure translocation by an AB single-chain toxin in intact cells.
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31
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Rossetto O, Pirazzini M, Montecucco C. Botulinum neurotoxins: genetic, structural and mechanistic insights. Nat Rev Microbiol 2014; 12:535-49. [PMID: 24975322 DOI: 10.1038/nrmicro3295] [Citation(s) in RCA: 400] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Botulinum neurotoxins (BoNTs) are produced by anaerobic bacteria of the genus Clostridium and cause a persistent paralysis of peripheral nerve terminals, which is known as botulism. Neurotoxigenic clostridia belong to six phylogenetically distinct groups and produce more than 40 different BoNT types, which inactivate neurotransmitter release owing to their metalloprotease activity. In this Review, we discuss recent studies that have improved our understanding of the genetics and structure of BoNT complexes. We also describe recent insights into the mechanisms of BoNT entry into the general circulation, neuronal binding, membrane translocation and neuroparalysis.
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Affiliation(s)
- Ornella Rossetto
- 1] Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [2] National Research Council Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [3]
| | - Marco Pirazzini
- 1] Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [2] National Research Council Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [3]
| | - Cesare Montecucco
- 1] Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [2] National Research Council Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy
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Li C, Wang Y, Zhang X, Deng L, Zhang Y, Chen Z. Tumor-targeted liposomal drug delivery mediated by a diseleno bond-stabilized cyclic peptide. Int J Nanomedicine 2013; 8:1051-62. [PMID: 23515368 PMCID: PMC3598503 DOI: 10.2147/ijn.s40498] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Peptide ligands have played an important role in tumor-targeted drug delivery as targeting moieties. The in vivo fate of peptide-mediated drug delivery systems and the following antitumor effects may greatly depend on the stability of the peptide ligand. In the current study, a tumor-targeting cyclic peptide screened by phage display, Lyp-1 (a peptide that specifically binds to tumor and endothelial cells of tumor lymphatics in certain tumors), was structurally modified by replacement of the original intramolecular disulfide bond with a diseleno bond. The produced analog Syp-1 (seleno derivative of Lyp-1) maintained specific binding ability to the target protein p32 (Kd = 18.54 nM), which is similar to that of Lyp-1 (Kd = 10.59 nM), indicated by surface plasmon resonance assay. Compared with Lyp-1, Syp-1 showed significantly improved stability against serum. After the peptide attached onto the surface of fluorophore-encapsulating liposomes, the more efficient tumor uptake of liposomal fluorophore mediated by Syp-1 was observed. Furthermore, Syp-1 modified liposomal doxorubicin presented the most potent tumor growth inhibitory ability among all the therapeutic groups, with a low half maximal inhibitory concentration of 588 nM against MDA-MB-435 cells in vitro and a high tumor inhibition rate of 73.5% in vivo. These findings clearly indicated that Syp-1 was a stable and effective tumor targeting ligand and suggest that the sulfur-to-selenium replacement strategy may help stabilize the phage-displayed cyclic peptide containing disulfide-bond under physiological conditions and strongly support the validity of peptide-mediated drug targeting.
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Affiliation(s)
- Chong Li
- Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People's Republic of China.
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Silva DS, Pereira LMG, Moreira AR, Ferreira-da-Silva F, Brito RM, Faria TQ, Zornetta I, Montecucco C, Oliveira P, Azevedo JE, Pereira PJB, Macedo-Ribeiro S, do Vale A, dos Santos NMS. The apoptogenic toxin AIP56 is a metalloprotease A-B toxin that cleaves NF-κb P65. PLoS Pathog 2013; 9:e1003128. [PMID: 23468618 PMCID: PMC3585134 DOI: 10.1371/journal.ppat.1003128] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 11/28/2012] [Indexed: 12/15/2022] Open
Abstract
AIP56 (apoptosis-inducing protein of 56 kDa) is a major virulence factor of Photobacterium damselae piscicida (Phdp), a Gram-negative pathogen that causes septicemic infections, which are among the most threatening diseases in mariculture. The toxin triggers apoptosis of host macrophages and neutrophils through a process that, in vivo, culminates with secondary necrosis of the apoptotic cells contributing to the necrotic lesions observed in the diseased animals. Here, we show that AIP56 is a NF-κB p65-cleaving zinc-metalloprotease whose catalytic activity is required for the apoptogenic effect. Most of the bacterial effectors known to target NF-κB are type III secreted effectors. In contrast, we demonstrate that AIP56 is an A-B toxin capable of acting at distance, without requiring contact of the bacteria with the target cell. We also show that the N-terminal domain cleaves NF-κB at the Cys39-Glu40 peptide bond and that the C-terminal domain is involved in binding and internalization into the cytosol. The apoptosis inducing protein of 56 kDa (AIP56) is a key virulence factor secreted by Photobacterium damselae piscicida (Phdp), a Gram-negative bacterium that causes septicaemic infections in economically important marine fish species. It is known that AIP56 induces massive destruction of the phagocytic cells of the infected host, allowing the extracellular multiplication of the bacteria and contributing to the genesis of the pathology. Here we show that AIP56 acts by cleaving NF-κB p65. The NF-κB family of transcription factors is evolutionarily conserved and plays a central role in the host responses to microbial pathogen invasion, regulating the expression of inflammatory and anti-apoptotic genes. Pathogenic bacteria have evolved complex strategies to interfere with NF-κB signalling, usually by injecting protein effectors directly into the cell's cytosol through bacterial secretion machineries that require contact with host cells. In contrast, AIP56 acts at distance and has an intrinsic ability to reach the cytosol due to the presence of a C-terminal domain that functions as “delivery module.”
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Affiliation(s)
- Daniela S. Silva
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Liliana M. G. Pereira
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ana R. Moreira
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Frederico Ferreira-da-Silva
- Protein Production and Purification, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Rui M. Brito
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Chemistry Department, Faculty of Science and Technology, University of Coimbra, Coimbra, Portugal
| | - Tiago Q. Faria
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Irene Zornetta
- Dipartimento di Scienze Biomediche dell'Università di Padova and Instituto di Neuroscienze del CNR, Padova, Italy
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche dell'Università di Padova and Instituto di Neuroscienze del CNR, Padova, Italy
| | - Pedro Oliveira
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Jorge E. Azevedo
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
- Organelle Biogenesis and Function, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Pedro J. B. Pereira
- Biomolecular Structure, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Sandra Macedo-Ribeiro
- Protein Crystallography, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana do Vale
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Nuno M. S. dos Santos
- Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- * E-mail:
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Rossetto O, Scorzeto M, Megighian A, Montecucco C. Tetanus neurotoxin. Toxicon 2013; 66:59-63. [PMID: 23419592 DOI: 10.1016/j.toxicon.2012.12.027] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 12/25/2012] [Accepted: 12/30/2012] [Indexed: 12/13/2022]
Affiliation(s)
- O Rossetto
- Department of Biomedical Sciences, University of Padova, and National Research Council Institute of Neuroscience, Italy
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35
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Yousefi M, Tahmasebi F, Younesi V, Razavi A, Khoshnoodi J, Bayat AA, Abbasi E, Rabbani H, Jeddi-Tehrani M, Shokri F. Characterization of neutralizing monoclonal antibodies directed against tetanus toxin fragment C. J Immunotoxicol 2013; 11:28-34. [DOI: 10.3109/1547691x.2013.763872] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Yousefi M, Khosravi-Eghbal R, Hemmati A, Shokri F. Production and characterization of recombinant light chain and carboxyterminal heavy chain fragments of tetanus toxin. Avicenna J Med Biotechnol 2013; 5:220-6. [PMID: 24285996 PMCID: PMC3838766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/19/2013] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Light chain (LC) and heavy chain carboxyterminal subdomain (HCC) fragments are the most important parts of tetanus neurotoxin (TeNT) which play key roles in toxicity and binding of TeNT, respectively. In the present study, these two fragments were cloned and expressed in a prokaryotic system and their identity was confirmed using anti-TeNT specific polyclonal and monoclonal antibodies. METHODS LC and HCC gene segments were amplified from Clostridium tetani genomic DNA by PCR, cloned into pET28b(+) cloning vector and transformed in Escherichia coli (E. coli) BL21(DE3) expression host. Recombinant proteins were then purified through His-tag using Nickel-based chromatography and characterized by SDS-PAGE, Western blotting and ELISA techniques. RESULTS Recombinant light chain and HCC fragments were successfully cloned and expressed in (E. coli) BL21 (DE3). Optimization of the induction protocol resulted in production of high levels of HCC (~35% of total bacterial protein) and to lesser extends of LC (~5%). Reactivity of the His-tag purified proteins with specific polyclonal and monoclonal antibodies confirmed their renatured structure and identity. CONCLUSION Our results indicate successful cloning and production of recombinant LC and HCC fragments of TeNT. These two recombinant proteins are potentially useful tools for screening and monitoring of anti-TeNT antibody response and vaccine production.
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Affiliation(s)
- Mehdi Yousefi
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran,Department of Immunology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran,These authors equally contributed to this work
| | - Roya Khosravi-Eghbal
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran,These authors equally contributed to this work
| | - Azam Hemmati
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Fazel Shokri
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran,Corresponding author: Fazel Shokri, Ph.D., Department of Immunology, School of Public Health Tehran University of Medical Sciences, Tehran, Iran. Tel: +98 21 88953021, Fax: +98 21 88954913. E-mail:
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38
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Molecular Modelling and Molecular Dynamics studies of GD1A, GD1B and their complexes with BoNT/B – Perspectives in interaction and specificity. J Struct Biol 2012; 180:497-508. [DOI: 10.1016/j.jsb.2012.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 08/14/2012] [Indexed: 11/23/2022]
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39
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The thioredoxin reductase-thioredoxin system is involved in the entry of tetanus and botulinum neurotoxins in the cytosol of nerve terminals. FEBS Lett 2012. [DOI: 10.1016/j.febslet.2012.11.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Pirazzini M, Rossetto O, Bolognese P, Shone CC, Montecucco C. Double anchorage to the membrane and intact inter-chain disulfide bond are required for the low pH induced entry of tetanus and botulinum neurotoxins into neurons. Cell Microbiol 2011; 13:1731-43. [PMID: 21790947 DOI: 10.1111/j.1462-5822.2011.01654.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Tetanus and botulinum neurotoxins are di-chain proteins that cause paralysis by inhibiting neuroexocytosis. These neurotoxins enter into nerve terminals via endocytosis inside synaptic vesicles, whose acidic pH induces a structural change of the neurotoxin molecule that becomes capable of translocating its L chain into the cytosol, via a transmembrane protein-conducting channel made by the H chain. This is the least understood step of the intoxication process primarily because it takes place inside vesicles within the cytosol. In the present study, we describe how this passage was made accessible to investigation by making it to occur at the surface of neurons. The neurotoxin, bound to the plasma membrane in the cold, was exposed to a warm low pH extracellular medium and the entry of the L chain was monitored by measuring its specific metalloprotease activity with a ratiometric method. We found that the neurotoxin has to be bound to the membrane via at least two anchorage sites in order for a productive low-pH induced structural change to take place. In addition, this process can only occur if the single inter-chain disulfide bond is intact. The pH dependence of the conformational change of tetanus neurotoxin and botulinum neurotoxin B, C and D is similar and take places in the same slightly acidic range, which comprises that present inside synaptic vesicles. Based on these and previous findings, we propose a stepwise sequence of molecular events that lead from toxin binding to membrane insertion.
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Affiliation(s)
- Marco Pirazzini
- Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Viale G. Colombo 3, 35131 Padova, Italy
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41
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Lebeda FJ, Singh BR. Membrane Channel activity and Translocation of Tetanus and Botulinum Neurotoxins. ACTA ACUST UNITED AC 2010. [DOI: 10.3109/15569549909036017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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42
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Chen C, Fu Z, Kim JJP, Barbieri JT, Baldwin MR. Gangliosides as high affinity receptors for tetanus neurotoxin. J Biol Chem 2009; 284:26569-77. [PMID: 19602728 PMCID: PMC2785345 DOI: 10.1074/jbc.m109.027391] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 06/19/2009] [Indexed: 12/19/2022] Open
Abstract
Tetanus neurotoxin (TeNT) is an exotoxin produced by Clostridium tetani that causes paralytic death to hundreds of thousands of humans annually. TeNT cleaves vesicle-associated membrane protein-2, which inhibits neurotransmitter release in the central nervous system to elicit spastic paralysis, but the molecular basis for TeNT entry into neurons remains unclear. TeNT is a approximately 150-kDa protein that has AB structure-function properties; the A domain is a zinc metalloprotease, and the B domain encodes a translocation domain and C-terminal receptor-binding domain (HCR/T). Earlier studies showed that HCR/T bound gangliosides via two carbohydrate-binding sites, termed the lactose-binding site (the "W" pocket) and the sialic acid-binding site (the "R" pocket). Here we report that TeNT high affinity binding to neurons is mediated solely by gangliosides. Glycan array and solid phase binding analyses identified gangliosides that bound exclusively to either the W pocket or the R pocket of TeNT; GM1a bound to the W pocket, and GD3 bound to the R pocket. Using these gangliosides and mutated forms of HCR/T that lacked one or both carbohydrate-binding pocket, gangliosides binding to both of the W and R pockets were shown to be necessary for high affinity binding to neuronal and non-neuronal cells. The crystal structure of a ternary complex of HCR/T with sugar components of two gangliosides bound to the W and R supported the binding of gangliosides to both carbohydrate pockets. These data show that gangliosides are functional dual receptors for TeNT.
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Affiliation(s)
- Chen Chen
- From the Departments of Microbiology and Molecular Genetics and
| | - Zhuji Fu
- Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Jung-Ja P. Kim
- Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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43
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Shi X, Garcia GE, Neill RJ, Gordon RK. TCEP treatment reduces proteolytic activity of BoNT/B in human neuronal SHSY-5Y cells. J Cell Biochem 2009; 107:1021-30. [DOI: 10.1002/jcb.22205] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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44
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Brunger AT, Rummel A. Receptor and substrate interactions of clostridial neurotoxins. Toxicon 2009; 54:550-60. [PMID: 19268493 PMCID: PMC2756235 DOI: 10.1016/j.toxicon.2008.12.027] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 12/01/2008] [Accepted: 12/02/2008] [Indexed: 01/27/2023]
Abstract
The high potency of clostridial neurotoxins relies predominantly on their neurospecific binding and specific hydrolysis of SNARE proteins. Their multi-step mode of mechanism can be ascribed to their multi-domain three-dimensional structure. The C-terminal H(CC)-domain interacts subsequently with complex polysialo-gangliosides such as GT1b and a synaptic vesicle protein receptor via two neighbouring binding sites, resulting in highly specific uptake of the neurotoxins at synapses of cholinergic motoneurons. After its translocation the enzymatically active light chain specifically hydrolyses specific SNARE proteins, preventing SNARE complex assembly and thereby blocking exocytosis of neurotransmitter.
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Affiliation(s)
- Axel T Brunger
- The Howard Hughes Medical Institute and Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences, Structural Biology, and Photon Science, Stanford University, J.H. Clark Center, E300C, 318 Campus Drive, Stanford, CA 94305, USA.
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45
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Shi X, Garcia GE, Nambiar MP, Gordon RK. Un-nicked BoNT/B activity in human SHSY-5Y neuronal cells. J Cell Biochem 2008; 105:129-35. [PMID: 18459116 DOI: 10.1002/jcb.21800] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BoNT/B holotoxin (HT) from the native source is a mixture of nicked and un-nicked forms. A previous study showed that while un-nicked HT could be transcytosed by intestinal epithelial cells, they did not correlate this with proteolytic activity or biological effect(s). Un-nicked HT is likely to be present in BoNT biological warfare agents (BWA), so it is important to investigate the relative toxicity of un-nicked HT in this BWA. To address this issue, we purified un-nicked HT from commercial sources and evaluated its ability to cleave substrates both in vitro and in vivo, and its effects on vesicle trafficking. The un-nicked HT was unable to cleave VAMPTide substrate used for in vitro proteolytic assays. Brief digestion of the un-nicked toxin with trypsin resulted in significant activation of the toxin proteolytic ability. SHSY-5Y human neuroblastoma cells were used to examine HT uptake and activation in vivo. Vesicle trafficking can be measured following K(+) stimulation of cells preloaded with [(3)H]-noradrenaline (NA). We found that highly purified un-nicked HT did inhibit NA release but at much reduced levels compared to the nicked toxin. That the reduction in NA release was due to BoNT effects on SNARE proteins was supported by the finding that VAMP-2 protein levels in un-nicked toxin treated cells was greater than those treated with nicked toxin. These results demonstrate that although un-nicked HT has markedly reduced toxicity than the nicked form, due to the preponderance in BoNT/B preparations from the native bacteria, it is a major source of toxicity.
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Affiliation(s)
- Xuerong Shi
- Department of Biochemical Pharmacology, Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910-7500, USA.
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46
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Behrensdorf-Nicol H, Kegel B, Bonifas U, Silberbach K, Klimek J, Weißer K, Krämer B. Residual enzymatic activity of the tetanus toxin light chain present in tetanus toxoid batches used for vaccine production. Vaccine 2008; 26:3835-41. [DOI: 10.1016/j.vaccine.2008.05.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 04/30/2008] [Accepted: 05/07/2008] [Indexed: 11/24/2022]
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47
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Affiliation(s)
- Eric A Johnson
- Department of Bacteriology, Food Research Institute, University of Wisconsin, Madison, WI, USA.
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48
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Abstract
Toxins that alter neurotransmitter release from nerve terminals are of considerable scientific and clinical importance. Many advances were recently made in the understanding of their molecular mechanisms of action and use in human therapy. Here, we focus on presynaptic neurotoxins, which are very potent inhibitors of the neurotransmitter release because they are endowed with specific enzymatic activities: (1) clostridial neurotoxins with a metallo-proteolytic activity and (2) snake presynaptic neurotoxins with a phospholipase A2 activity.
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Affiliation(s)
- Ornella Rossetto
- Departimento de Scienze Biomediche and Istituto CNR di Neuroscienze, Universita di Padova, Viale G. Colombo 3, 35121, Padova, Italy
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49
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Kegel B, Behrensdorf-Nicol HA, Bonifas U, Silberbach K, Klimek J, Krämer B, Weisser K. An in vitro assay for detection of tetanus neurotoxin activity: Using antibodies for recognizing the proteolytically generated cleavage product. Toxicol In Vitro 2007; 21:1641-9. [PMID: 17826026 DOI: 10.1016/j.tiv.2007.06.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 06/22/2007] [Accepted: 06/27/2007] [Indexed: 11/30/2022]
Abstract
Tetanus neurotoxin (TeNT(1)) is a bacterial protease which specifically cleaves the vesicle protein synaptobrevin-2 (vesicle associated membrane protein-2, VAMP-2). This proteolytic feature of the toxin has been used to develop a sensitive endopeptidase assay for the detection of TeNT activity as an alternative to the in vivo assay for TeNT toxicity. Recombinant synaptobrevin-2 (rSyb2) is immobilized onto a microtiter plate, and the cleavage of immobilized rSyb2 by TeNT is detected with a polyclonal antibody directed against the newly generated C-terminus of the cleavage product. This antibody is shown to be a highly specific tool for detecting rSyb2 proteolysis by TeNT. The method reaches a detection limit of less than 1pg TeNT/ml. To our knowledge, this is the most sensitive in vitro assay for the detection of TeNT activity, and it is easy to perform. Besides, the assay can also detect the activity of botulinum neurotoxin type B (BoNT/B). The method can be applied to examine the toxicity of TeNT or BoNT/B preparations as well as the influence of chemicals on TeNT and BoNT/B activity. In the future, the assay may also serve as a basis for the replacement of the in vivo safety control of tetanus vaccines.
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Affiliation(s)
- B Kegel
- Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
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50
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Qazi O, Bolgiano B, Crane D, Svergun DI, Konarev PV, Yao ZP, Robinson CV, Brown KA, Fairweather N. The HC Fragment of Tetanus Toxin forms Stable, Concentration-dependent Dimers via an Intermolecular Disulphide Bond. J Mol Biol 2007; 365:123-34. [PMID: 17056064 DOI: 10.1016/j.jmb.2006.09.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 09/18/2006] [Accepted: 09/19/2006] [Indexed: 11/27/2022]
Abstract
Protein oligomerisation is a prerequisite for the toxicity of a number of bacterial toxins. Examples include the pore-forming cytotoxin streptolysin O, which oligomerises to form large pores in the membrane and the protective antigen of anthrax toxin, where a heptameric complex is essential for the delivery of lethal factor and edema factor to the cell cytosol. Binding of the clostridial neurotoxins to receptors on neuronal cells is well characterised, but little is known regarding the quaternary structure of these toxins and the role of oligomerisation in the intoxication process. We have investigated the oligomerisation of the receptor binding domain (H(C)) of tetanus toxin, which retains the binding and trafficking properties of the full-length toxin. Electrophoresis, size exclusion chromatography and mass spectrometry were used to demonstrate that H(C) undergoes concentration-dependent oligomerisation in solution. Reducing agents were found to affect H(C) oligomerisation and, using mutagenesis, Cys869 was shown to be essential for this process. Furthermore, the oligomeric state and quaternary structure of H(C) in solution was assessed using synchrotron small-angle X-ray scattering. Ab initio shape analysis and rigid body modelling coupled with mutagenesis data allowed the construction of an unequivocal model of dimeric H(C) in solution. We propose a possible mechanism for H(C) oligomerisation and discuss how this may relate to toxicity.
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Affiliation(s)
- Omar Qazi
- Division of Cell and Molecular Biology, Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
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