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Learoyd TP. Underreporting or Failed Notification? Global Botulism Reporting, 2000-2022. Health Secur 2024; 22:203-209. [PMID: 38768418 DOI: 10.1089/hs.2023.0081] [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] [Indexed: 05/22/2024] Open
Abstract
Botulism is a rare, potentially fatal illness caused by botulinum toxins produced by Clostridium bacteria. There are no coordinated worldwide reporting mechanisms for botulism cases and therefore few reliable case frequency estimates. This study aimed to establish an international benchmark for case frequency to determine estimated global rates of underreporting of botulism cases. To this end, a comprehensive, multilingual search of major global and national databases, including gray data and government sources, was performed. Data from case series were pooled, standardized against United Nations midyear population estimates, and analyzed using Kolmogorov-Smirnov tests to identify normally distributed data series. National incidence rates of normally distributed series were compared with that of the United States, which was considered the gold standard due to its extensive data reported for 2004-2018. A total of 6,932 botulism cases from 59 nations were identified in the literature, with a global case fatality rate of 1.37%. The national mean incidence rate ranged from 0.00 to 8.04 cases per million people, with an international mean incidence rate of 0.62 cases per million people. At the continent level, incidence rates tended toward normal distributions, although few countries outside of North America and Europe exhibited normal distributions. Based on comparisons with the US standard, an estimated 88.71% of botulism cases worldwide were unreported in 2016. Better awareness of botulism among healthcare professionals, coordinated global reporting mechanisms, and research on additional contributing factors to underreporting would enable better understanding of global case frequency, thereby potentially reducing the global incidence of botulism and improving outcomes.
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Affiliation(s)
- Tristan P Learoyd
- Tristan P. Learoyd, MPharm, PGCE, GradDipLaw, MA, MBA, MSc, PhD, MRPharmS, FHEA, is Director of Global Health Programs, Emergent BioSolutions UK Ltd, London, United Kingdom
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2
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Dorner MB, Wilking H, Skiba M, Wilk L, Steinberg M, Worbs S, Çeken S, Kaygusuz S, Simon S, Becher F, Mikolajewska A, Kornschober C, Bütler T, Jourdan-Da-Silva N, An der Heiden M, Schaade L, Stark K, Dorner BG, Frank C. A large travel-associated outbreak of iatrogenic botulism in four European countries following intragastric botulinum neurotoxin injections for weight reduction, Türkiye, February to March 2023. Euro Surveill 2023; 28:2300203. [PMID: 37289431 PMCID: PMC10318948 DOI: 10.2807/1560-7917.es.2023.28.23.2300203] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 05/14/2023] [Indexed: 06/09/2023] Open
Abstract
In March 2023, 34 associated cases of iatrogenic botulism were detected in Germany (30 cases), Switzerland (two cases), Austria (one case), and France (one case). An alert was rapidly disseminated via European Union networks and communication platforms (Food- and Waterborne Diseases and Zoonoses Network, EpiPulse, Early Warning and Response System) and the International Health Regulation mechanism; the outbreak was investigated in a European collaboration. We traced sources of the botulism outbreak to treatment of weight loss in Türkiye, involving intragastric injections of botulinum neurotoxin. Cases were traced using a list of patients who had received this treatment. Laboratory investigations of the first 12 German cases confirmed nine cases. The application of innovative and highly sensitive endopeptidase assays was necessary to detect minute traces of botulinum neurotoxin in patient sera. The botulism notification requirement for physicians was essential to detect this outbreak in Germany. The surveillance case definition of botulism should be revisited and inclusion of cases of iatrogenic botulism should be considered as these cases might lack standard laboratory confirmation yet warrant public health action. Any potential risks associated with the use of botulinum neurotoxins in medical procedures need to be carefully balanced with the expected benefits of the procedure.
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Affiliation(s)
- Martin Bernhard Dorner
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Hendrik Wilking
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Martin Skiba
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Laura Wilk
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Maximilian Steinberg
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Sylvia Worbs
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Sabahat Çeken
- General Directorate of Public Health, Ministry of Health, Ankara, Türkiye
| | - Sedat Kaygusuz
- General Directorate of Public Health, Ministry of Health, Ankara, Türkiye
| | - Stéphanie Simon
- Université Paris Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE), Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - François Becher
- Université Paris Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE), Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - Agata Mikolajewska
- Strategy and Incident Response (ZBS7), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | | | - Timo Bütler
- National International Health Regulation (IHR) Focal Point for Switzerland, Swiss Federal Office of Public Health, Division of Communicable Diseases, Bern, Switzerland
| | | | - Maria An der Heiden
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Lars Schaade
- Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Klaus Stark
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Brigitte Gertrud Dorner
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
- These authors contributed equally to the work and share the last authorship
| | - Christina Frank
- These authors contributed equally to the work and share the last authorship
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
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Fonfria E, Marks E, Foulkes LM, Schofield R, Higazi D, Coward S, Kippen A. Replacement of the Mouse LD 50 Assay for Determination of the Potency of AbobotulinumtoxinA with a Cell-Based Method in Both Powder and Liquid Formulations. Toxins (Basel) 2023; 15:toxins15050314. [PMID: 37235349 DOI: 10.3390/toxins15050314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/18/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) are important therapeutic agents. The in vivo median lethal dose (LD50) assay has been commonly used to measure the potency of BoNT commercial preparations. As an alternative, we developed cell-based assays for abobotulinumtoxinA in both powder (Dysport®, Azzalure®) and liquid (Alluzience®) formulations using the in vitro BoCell® system. The assays demonstrated linearity over 50-130% of the expected relative potency, with a correlation coefficient of 0.98. Mean recoveries of 90-108% of the stated potency were observed over this range. The coefficients of variation for powder and liquid formulations, respectively, were 3.6% and 4.0% for repeatability and 8.3% and 5.0% for intermediate precision. A statistically powered comparability assessment of the BoCell® and LD50 assays was performed. Equivalence was demonstrated between the assays for the liquid formulation at release and end of shelf life using a paired equivalence test with predefined equivalence margins. For the powder formulation, the assays were also shown to be equivalent for release samples and when determining loss of potency following thermal degradation. The BoCell® assay was approved for establishing the potency of abobotulinumtoxinA for both powder and liquid formulations in Europe and for the powder formulation only in the USA.
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Affiliation(s)
| | | | | | | | | | - Sam Coward
- Ipsen Biopharm Ltd., Wrexham LL13 9UF, UK
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Hendrickx D, Varela Martínez C, Contzen M, Wagner-Wiening C, Janke KH, Hernando Jiménez P, Massing S, Pichler J, Tichaczek-Dischinger P, Burckhardt F, Stark K, Katz K, Jurke A, Thole S, Carbó R, del Pobil Ferré MP, Nieto M, Zamora MJ, Sisó A, Pallares García P, Valdezate S, Schaade L, Worbs S, Dorner BG, Frank C, Dorner MB. First cross-border outbreak of foodborne botulism in the European Union associated with the consumption of commercial dried roach ( Rutilus rutilus). Front Public Health 2023; 10:1039770. [PMID: 36684858 PMCID: PMC9846170 DOI: 10.3389/fpubh.2022.1039770] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 12/05/2022] [Indexed: 01/05/2023] Open
Abstract
Botulism outbreaks due to commercial products are extremely rare in the European Union. Here we report on the first international outbreak of foodborne botulism caused by commercial salt-cured, dried roach (Rutilus rutilus). Between November and December 2016, an outbreak of six foodborne botulism type E cases from five unrelated households was documented in Germany and Spain. The outbreak involved persons of Russian and Kazakh backgrounds, all consumed unheated salt-cured, dried roach-a snack particularly favored in Easter-European countries. The implicated food batches had been distributed by an international wholesaler and were recalled from Europe-wide outlets of a supermarket chain and other independent retailers. Of interest, and very unlike to other foodborne disease outbreaks which usually involves a single strain or virus variant, different Clostridium botulinum strains and toxin variants could be identified even from a single patient's sample. Foodborne botulism is a rare but potentially life-threatening disease and almost exclusively involves home-made or artisan products and thus, outbreaks are limited to individual or few cases. As a consequence, international outbreaks are the absolute exception and this is the first one within the European Union. Additional cases were likely prevented by a broad product recall, underscoring the importance of timely public health action. Challenges and difficulties on the diagnostic and epidemiological level encountered in the outbreak are highlighted.
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Affiliation(s)
- David Hendrickx
- Landesgesundheitsamt Baden-Württemberg, Ministerium für Soziales, Gesundheit und Integration Baden-Württemberg, Stuttgart, Germany
- European Centre for Disease Prevention and Control, European Programme for Intervention Epidemiology Training (EPIET), Stockholm, Sweden
| | - Carmen Varela Martínez
- National Centre of Epidemiology, Institute of Health Carlos III, Madrid, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Institute of Health Carlos III, Madrid, Spain
| | - Matthias Contzen
- Chemisches und Veterinäruntersuchungsamt Stuttgart, Ministerium für Ernährung, Ländlichen Raum und Verbraucherschutz Baden-Württemberg, Fellbach, Germany
| | - Christiane Wagner-Wiening
- Landesgesundheitsamt Baden-Württemberg, Ministerium für Soziales, Gesundheit und Integration Baden-Württemberg, Stuttgart, Germany
| | - Karl-Heinz Janke
- Landesgesundheitsamt Baden-Württemberg, Ministerium für Soziales, Gesundheit und Integration Baden-Württemberg, Stuttgart, Germany
| | - Pablo Hernando Jiménez
- Chemisches und Veterinäruntersuchungsamt Karlsruhe, Ministerium für Ernährung, Ländlichen Raum und Verbraucherschutz Baden Württemberg, Karlsruhe, Germany
| | - Susanne Massing
- Landratsamt Böblingen, Veterinärdienst und Lebensmittelüberwachung, Böblingen, Germany
| | | | - Petra Tichaczek-Dischinger
- Chemisches und Veterinäruntersuchungsamt Stuttgart, Ministerium für Ernährung, Ländlichen Raum und Verbraucherschutz Baden-Württemberg, Fellbach, Germany
| | - Florian Burckhardt
- Landesuntersuchungsamt Rheinland-Pfalz, Rhineland-Palatinate, Koblenz, Germany
| | - Klaus Stark
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Katharina Katz
- GE 2.3 Epidemiologie übertragbarer Krankheiten, Landesamt für Gesundheit und Lebensmittelsicherheit, Oberschleißheim, Germany
| | - Annette Jurke
- Landeszentrum Gesundheit Nordrhein-Westfalen, North Rhine-Westphalia, Bochum, Germany
| | - Sebastian Thole
- Landeszentrum Gesundheit Nordrhein-Westfalen, North Rhine-Westphalia, Bochum, Germany
| | - Rosa Carbó
- Servicio de Vigilancia y Control Epidemiológico, Dirección General de Salud Pública, Valencia, Spain
| | | | - Milagros Nieto
- National Food Centre (CNA), Spanish Agency for Consumer Affairs Food Safety (AESAN), Majadahonda, Spain
| | - María Jesús Zamora
- National Food Centre (CNA), Spanish Agency for Consumer Affairs Food Safety (AESAN), Majadahonda, Spain
| | - Ana Sisó
- National Food Centre (CNA), Spanish Agency for Consumer Affairs Food Safety (AESAN), Majadahonda, Spain
| | | | - Sylvia Valdezate
- National Centre of Microbiology, Institute of Health Carlos III, Madrid, Spain
| | - Lars Schaade
- Consultant Laboratory for Neurotoxin-Producing Clostridia (Botulism, Tetanus), Robert Koch Institute, Berlin, Germany
| | - Sylvia Worbs
- Consultant Laboratory for Neurotoxin-Producing Clostridia (Botulism, Tetanus), Robert Koch Institute, Berlin, Germany
| | - Brigitte Gertrud Dorner
- Consultant Laboratory for Neurotoxin-Producing Clostridia (Botulism, Tetanus), Robert Koch Institute, Berlin, Germany
| | - Christina Frank
- Landesuntersuchungsamt Rheinland-Pfalz, Rhineland-Palatinate, Koblenz, Germany
| | - Martin Bernhard Dorner
- Consultant Laboratory for Neurotoxin-Producing Clostridia (Botulism, Tetanus), Robert Koch Institute, Berlin, Germany
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5
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Rasetti-Escargueil C, Popoff MR. Recent Developments in Botulinum Neurotoxins Detection. Microorganisms 2022; 10:microorganisms10051001. [PMID: 35630444 PMCID: PMC9145529 DOI: 10.3390/microorganisms10051001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 04/29/2022] [Accepted: 05/03/2022] [Indexed: 02/04/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) are produced as protein complexes by bacteria of the genus Clostridium that are Gram-positive, anaerobic and spore forming (Clostridium botulinum, C. butyricum, C. baratii and C. argentinense spp.). BoNTs show a high immunological and genetic diversity. Therefore, fast, precise, and more reliable detection methods are still required to monitor outbreaks and ensure surveillance of botulism. The botulinum toxin field also comprises therapeutic uses, basic research studies and biodefense issues. This review presents currently available detection methods, and new methods offering the potential of enhanced precision and reproducibility. While the immunological methods offer a range of benefits, such as rapid analysis time, reproducibility and high sensitivity, their implementation is subject to the availability of suitable tools and reagents, such as specific antibodies. Currently, the mass spectrometry approach is the most sensitive in vitro method for a rapid detection of active or inactive forms of BoNTs. However, these methods require inter-laboratory validation before they can be more widely implemented in reference laboratories. In addition, these surrogate in vitro models also require full validation before they can be used as replacement bioassays of potency. Cell-based assays using neuronal cells in culture recapitulate all functional steps of toxin activity, but are still at various stages of development; they are not yet sufficiently robust, due to high batch-to-batch cell variability. Cell-based assays have a strong potential to replace the mouse bioassay (MBA) in terms of BoNT potency determination in pharmaceutical formulations; they can also help to identify suitable inhibitors while reducing the number of animals used. However, the development of safe countermeasures still requires the use of in vivo studies to complement in vitro immunological or cell-based approaches.
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Fabris F, Šoštarić P, Matak I, Binz T, Toffan A, Simonato M, Montecucco C, Pirazzini M, Rossetto O. Detection of VAMP Proteolysis by Tetanus and Botulinum Neurotoxin Type B In Vivo with a Cleavage-Specific Antibody. Int J Mol Sci 2022; 23:ijms23084355. [PMID: 35457172 PMCID: PMC9024618 DOI: 10.3390/ijms23084355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/08/2022] [Accepted: 04/12/2022] [Indexed: 11/17/2022] Open
Abstract
Tetanus and Botulinum type B neurotoxins are bacterial metalloproteases that specifically cleave the vesicle-associated membrane protein VAMP at an identical peptide bond, resulting in inhibition of neuroexocytosis. The minute amounts of these neurotoxins commonly used in experimental animals are not detectable, nor is detection of their VAMP substrate sensitive enough. The immune detection of the cleaved substrate is much more sensitive, as we have previously shown for botulinum neurotoxin type A. Here, we describe the production in rabbit of a polyclonal antibody raised versus a peptide encompassing the 13 residues C-terminal with respect to the neurotoxin cleavage site. The antibody was affinity purified and found to recognize, with high specificity and selectivity, the novel N-terminus of VAMP that becomes exposed after cleavage by tetanus toxin and botulinum toxin type B. This antibody recognizes the neoepitope not only in native and denatured VAMP but also in cultured neurons and in neurons in vivo in neurotoxin-treated mice or rats, suggesting the great potential of this novel tool to elucidate tetanus and botulinum B toxin activity in vivo.
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Affiliation(s)
- Federico Fabris
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy; (F.F.); (C.M.)
| | - Petra Šoštarić
- Department of Pharmacology, School of Medicine, University of Zagreb, Šalata 11, 10000 Zagreb, Croatia; (P.Š.); (I.M.)
| | - Ivica Matak
- Department of Pharmacology, School of Medicine, University of Zagreb, Šalata 11, 10000 Zagreb, Croatia; (P.Š.); (I.M.)
| | - Thomas Binz
- Institute of Cellular Biochemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany;
| | - Anna Toffan
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell’Università 10, 35020 Legnaro, Italy;
| | - Morena Simonato
- Institute of Neuroscience, Italian Research Council, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy;
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy; (F.F.); (C.M.)
- Institute of Neuroscience, Italian Research Council, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy;
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy; (F.F.); (C.M.)
- Interdepartmental Research Center of Myology CIR-Myo, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy
- Correspondence: (M.P.); (O.R.)
| | - Ornella Rossetto
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy; (F.F.); (C.M.)
- Institute of Neuroscience, Italian Research Council, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy;
- Interdepartmental Research Center of Myology CIR-Myo, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy
- Correspondence: (M.P.); (O.R.)
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8
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Kumar DN, Baider Z, Elad D, Blum SE, Shtenberg G. Botulinum Neurotoxin C Dual Detection through Immunological Recognition and Endopeptidase Activity Using Porous Silicon Interferometers. Anal Chem 2022; 94:5927-5936. [PMID: 35385264 DOI: 10.1021/acs.analchem.2c00255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins known in nature produced by Clostridium botulinum strains, which can cause life-threatening diseases in both humans and animals. The latter is of serious environmental and economic concern, resulting in high mortality, production losses, and rejection of contaminated animal feed. The available in vivo mouse assay is inadequate for real-time and on-site assessment of outbreaks. Herein, we present a reflective-based approach for the detection of BoNT/C while estimating its activity. Two adjacent porous Si Fabry-Pérot interferometers are simultaneously utilized to quantify minute BoNT/C concentrations by a competitive immunoassay and to assess their endopeptidase activity. The reflectivity signals of each interferometer are amplified by biochemical reaction products infiltration into the scaffold or by peptide fragments detachment from the nanostructure. The optical assay is highly sensitive in compliance with the in vivo approach by presenting a detection limit of 4.24 pg mL-1. The specificity and selectivity of the designed platform are cross-validated against BoNT/B and BoNT/D, also relevant to animal health. Finally, the analytical performances of both interferometers for real-life scenarios are confirmed using actual toxins while depicting excellent compliance to complex media analysis. Overall, the presented sensing scheme offers an efficient, rapid, and label-free approach for potential biodiagnostic elucidation of botulism outbreaks.
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Affiliation(s)
- D Nanda Kumar
- Institute of Agricultural Engineering, ARO, Volcani Institute, Rishon LeZion 7505101, Israel
| | - Zina Baider
- Botulism National Reference Laboratory, Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan 50200, Israel
| | - Daniel Elad
- Botulism National Reference Laboratory, Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan 50200, Israel
| | - Shlomo E Blum
- Botulism National Reference Laboratory, Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan 50200, Israel
| | - Giorgi Shtenberg
- Institute of Agricultural Engineering, ARO, Volcani Institute, Rishon LeZion 7505101, Israel
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Highly Specific Monoclonal Antibody Targeting the Botulinum Neurotoxin Type E Exposed SNAP-25 Neoepitope. Antibodies (Basel) 2022; 11:antib11010021. [PMID: 35323195 PMCID: PMC8944829 DOI: 10.3390/antib11010021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/07/2022] [Accepted: 03/13/2022] [Indexed: 12/31/2022] Open
Abstract
Botulinum neurotoxin type E (BoNT/E), the fastest acting toxin of all BoNTs, cleaves the 25 kDa synaptosomal-associated protein (SNAP-25) in motor neurons, leading to flaccid paralysis. The specific detection and quantification of the BoNT/E-cleaved SNAP-25 neoepitope can facilitate the development of cell-based assays for the characterization of anti-BoNT/E antibody preparations. In order to isolate highly specific monoclonal antibodies suitable for the in vitro immuno-detection of the exposed neoepitope, mice and rabbits were immunized with an eight amino acid peptide composed of the C-terminus of the cleaved SNAP-25. The immunized rabbits developed a specific and robust polyclonal antibody response, whereas the immunized mice mostly demonstrated a weak antibody response that could not discriminate between the two forms of SNAP-25. An immune scFv phage-display library was constructed from the immunized rabbits and a panel of antibodies was isolated. The sequence alignment of the isolated clones revealed high similarity between both heavy and light chains with exceptionally short HCDR3 sequences. A chimeric scFv-Fc antibody was further expressed and characterized, exhibiting a selective, ultra-high affinity (pM) towards the SNAP-25 neoepitope. Moreover, this antibody enabled the sensitive detection of cleaved SNAP-25 in BoNT/E treated SiMa cells with no cross reactivity with the intact SNAP-25. Thus, by applying an immunization and selection procedure, we have isolated a novel, specific and high-affinity antibody against the BoNT/E-derived SNAP-25 neoepitope. This novel antibody can be applied in in vitro assays that determine the potency of antitoxin preparations and reduce the use of laboratory animals for these purposes.
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10
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Nowakowska MB, Selby K, Przykopanski A, Krüger M, Krez N, Dorner BG, Dorner MB, Jin R, Minton NP, Rummel A, Lindström M. Construction and validation of safe Clostridium botulinum Group II surrogate strain producing inactive botulinum neurotoxin type E toxoid. Sci Rep 2022; 12:1790. [PMID: 35110559 PMCID: PMC8810926 DOI: 10.1038/s41598-022-05008-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/24/2021] [Indexed: 01/05/2023] Open
Abstract
Botulinum neurotoxins (BoNTs), produced by the spore-forming bacterium Clostridium botulinum, cause botulism, a rare but fatal illness affecting humans and animals. Despite causing a life-threatening disease, BoNT is a multipurpose therapeutic. Nevertheless, as the most potent natural toxin, BoNT is classified as a Select Agent in the US, placing C. botulinum research under stringent governmental regulations. The extreme toxicity of BoNT, its impact on public safety, and its diverse therapeutic applications urge to devise safe solutions to expand C. botulinum research. Accordingly, we exploited CRISPR/Cas9-mediated genome editing to introduce inactivating point mutations into chromosomal bont/e gene of C. botulinum Beluga E. The resulting Beluga Ei strain displays unchanged physiology and produces inactive BoNT (BoNT/Ei) recognized in serological assays, but lacking biological activity detectable ex- and in vivo. Neither native single-chain, nor trypsinized di-chain form of BoNT/Ei show in vivo toxicity, even if isolated from Beluga Ei sub-cultured for 25 generations. Beluga Ei strain constitutes a safe alternative for the BoNT research necessary for public health risk management, the development of food preservation strategies, understanding toxinogenesis, and for structural BoNT studies. The example of Beluga Ei generation serves as template for future development of C. botulinum producing different inactive BoNT serotypes.
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Affiliation(s)
- Maria B Nowakowska
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Katja Selby
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Adina Przykopanski
- Institut Für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Maren Krüger
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Nadja Krez
- Institut Für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Brigitte G Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Martin B Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Rongsheng Jin
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
| | - Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Andreas Rummel
- Institut Für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Miia Lindström
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
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Plößl T, Vujtovic-Ockenga N, Kehrenberg C, Klaubert B. Multi-dimensional nanoscale liquid chromatography and nano-electrospray ion-trap mass spectrometry for detection of Clostridium botulinum type C and the produced botulinum neurotoxin type C complex. J Microbiol Methods 2021; 193:106397. [PMID: 34952090 DOI: 10.1016/j.mimet.2021.106397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 12/16/2021] [Accepted: 12/16/2021] [Indexed: 12/18/2022]
Abstract
Botulinum neurotoxin types C, D and their mosaic forms C/D and D/C produced mainly by Clostridium botulinum types C and D cause botulism in animals and belong to the most toxic substances for poultry and fish. In addition to intoxications, also toxoinfections with C. botulinum types C and D play a role that should not be underestimated, especially in veterinary medicine. Contrary to other botulinum neurotoxin complexes (BT x), the biosynthesis of these types is phage-encoded. Currently, the gold standard for neurotoxin detection in cases of clinical botulism is the mouse bioassay. In the last few years, alternatives for replacing this mouse bioassay have become increasingly interesting for the detection and characterisation of botulinum neurotoxins. Therefore, immunological techniques based mainly on antibodies, PCR or mass spectral methods have been developed. In this context, the most promising development is that of different endopeptidase assays. In our study, we were able to show that the 2D-nano-LC-MS/MS method presented by Klaubert et al. 2009 especially for detecting BT x A, B, E and F in complex culture media can also be used for detecting BT x C. The focus was therefore on transferring this method to detecting BT x C and pointing out necessary modifications of this current method. For method development, we used different culture preparations and sample conditions. To find out whether BT x C is just as stable against acetic peptic pretreatment as other BT x, we used sample preparations with and without peptic pretreatment. The decisive difference to previous publications is the detection of produced BT x C directly from culture supernatant of different strains of C. botulinum type C. In addition, we present a new approach of detecting protein fragments from C3 and C2 toxin and some specific host cell proteins of the bacterium Clostridium spp. in order to specify the carrier bacterium, therefore verifying the presence of an intact neurotoxin-encoding phage also without directly detecting BT x C and thus the possibility to produce neurotoxin. Herein, we describe a new method to examine environmental samples or suspected feed samples in cases of toxoinfections as well as finding out the causes of clinical botulism. This new approach is particularly interesting for veterinary medicine, especially for diseases like chronic botulism in cows or equine grass sickness.
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Affiliation(s)
- Tanja Plößl
- Supervisory Centre South for Public Law Tasks of the Bundeswehr Medical Service, Dachauer Straße 128, 80637 München, Germany.
| | - Nada Vujtovic-Ockenga
- Central Institute of the Bundeswehr Medical Service Munich, Ingolstädter Landstraße 102, 85748 Garching-Hochbrück, Germany
| | - Corinna Kehrenberg
- Institute for Veterinary Food Science, Justus-Liebig-University, Frankfurter Straße 92, 35392 Gießen, Germany
| | - Bernd Klaubert
- Federal Ministry of Health, Friedrichstraße 108, 10117 Berlin, Germany
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12
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Botulinum Neurotoxin-C Detection Using Nanostructured Porous Silicon Interferometer. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9080228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Botulinum neurotoxins (BoNT) are the most potent toxins, which are produced by Clostridium bacteria and cause the life-threatening disease of botulism in all vertebrates. Specifically, animal botulism represents a serious environmental and economic concern in animal production due to the high mortality rates observed during outbreaks. Despite the availability of vaccines against BoNT, there are still many outbreaks of botulism worldwide. Alternative assays capable of replacing the conventional in vivo assay in terms of rapid and sensitive quantification, and the applicability for on-site analysis, have long been perused. Herein, we present a simple, highly sensitive and label-free optical biosensor for real-time detection of BoNT serotype C using a porous silicon Fabry–Pérot interferometer. A competitive immunoassay coupled to a biochemical cascade reaction was adapted for optical signal amplification. The resulting insoluble precipitates accumulated within the nanostructure changed the reflectivity spectra by alternating the averaged refractive index. The augmented optical performance allowed for a linear response within the range of 10 to 10,000 pg mL−1 while presenting a detection limit of 4.8 pg mL−1. The practical aspect of the developed assay was verified using field BoNT holotoxins to exemplify the potential use of the developed optical approach for rapid bio-diagnosis of BoNT. The specificity and selectivity of the assay were successfully validated using an adjacent holotoxin relevant for farm animals (BoNT serotype D). Overall, this work sets the foundation for implementing a miniaturized interferometer for routine on-site botulism diagnosis, thus significantly reducing the need for animal experimentation and shortening analysis turnaround for early evidence-based therapy.
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Wagner HJ, Mohsenin H, Weber W. Synthetic Biology-Empowered Hydrogels for Medical Diagnostics. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2021; 178:197-226. [PMID: 33582837 DOI: 10.1007/10_2020_158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Synthetic biology is strongly inspired by concepts of engineering science and aims at the design and generation of artificial biological systems in different fields of research such as diagnostics, analytics, biomedicine, or chemistry. To this aim, synthetic biology uses an engineering approach relying on a toolbox of molecular sensors and switches that endows cellular hosts with non-natural computing functions and circuits. Importantly, this concept is not only limited to cellular approaches. Synthetic biological building blocks have also conferred sensing and switching capability to otherwise inactive materials. This principle has attracted high interest for the development of biohybrid materials capable of sensing and responding to specific molecular stimuli, such as disease biomarkers, antibiotics, or heavy metals. Moreover, the interconnection of individual sense-and-respond materials to complex materials systems has enabled the processing of, for example, multiple inputs or the amplification of signals using feedback topologies. Such systems holding high potential for applications in the analytical and diagnostic sectors will be described in this chapter.
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Affiliation(s)
- Hanna J Wagner
- Faculty of Biology, Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg im Breisgau, Germany.,Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Hasti Mohsenin
- Faculty of Biology, Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg im Breisgau, Germany
| | - Wilfried Weber
- Faculty of Biology, Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg im Breisgau, Germany.
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14
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Palazón-García R, Benavente-Valdepeñas AM. Botulinum Toxin: From Poison to Possible Treatment for Spasticity in Spinal Cord Injury. Int J Mol Sci 2021; 22:ijms22094886. [PMID: 34063051 PMCID: PMC8125452 DOI: 10.3390/ijms22094886] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 12/18/2022] Open
Abstract
Botulism has been known for about three centuries, and since its discovery, botulinum toxin has been considered one of the most powerful toxins. However, throughout the 20th century, several medical applications have been discovered, among which the treatment of spasticity stands out. Botulinum toxin is the only pharmacological treatment recommended for spasticity of strokes and cerebral palsy. Although its use as an adjuvant treatment against spasticity in spinal cord injuries is not even approved, botulinum toxin is being used against such injuries. This article describes the advances that have been made throughout history leading to the therapeutic use of botulinum toxin and, in particular, its application to the treatment of spasticity in spinal cord injury.
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Affiliation(s)
- Ramiro Palazón-García
- Physical Medicine and Rehabilitation Department, Hospital Nacional de Parapléjicos, 45004 Toledo, Spain
- Correspondence:
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15
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Multiplex Immunoassay Techniques for On-Site Detection of Security Sensitive Toxins. Toxins (Basel) 2020; 12:toxins12110727. [PMID: 33233770 PMCID: PMC7699850 DOI: 10.3390/toxins12110727] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/12/2020] [Accepted: 11/16/2020] [Indexed: 12/12/2022] Open
Abstract
Biological toxins are a heterogeneous group of high molecular as well as low molecular weight toxins produced by living organisms. Due to their physical and logistical properties, biological toxins are very attractive to terrorists for use in acts of bioterrorism. Therefore, among the group of biological toxins, several are categorized as security relevant, e.g., botulinum neurotoxins, staphylococcal enterotoxins, abrin, ricin or saxitoxin. Additionally, several security sensitive toxins also play a major role in natural food poisoning outbreaks. For a prompt response to a potential bioterrorist attack using biological toxins, first responders need reliable, easy-to-use and highly sensitive methodologies for on-site detection of the causative agent. Therefore, the aim of this review is to present on-site immunoassay platforms for multiplex detection of biological toxins. Furthermore, we introduce several commercially available detection technologies specialized for mobile or on-site identification of security sensitive toxins.
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16
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Toxemia in Human Naturally Acquired Botulism. Toxins (Basel) 2020; 12:toxins12110716. [PMID: 33202855 PMCID: PMC7697460 DOI: 10.3390/toxins12110716] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/18/2022] Open
Abstract
Human botulism is a severe disease characterized by flaccid paralysis and inhibition of certain gland secretions, notably salivary secretions, caused by inhibition of neurotransmitter release. Naturally acquired botulism occurs in three main forms: food-borne botulism by ingestion of preformed botulinum neurotoxin (BoNT) in food, botulism by intestinal colonization (infant botulism and intestinal toxemia botulism in infants above one year and adults), and wound botulism. A rapid laboratory confirmation of botulism is required for the appropriate management of patients. Detection of BoNT in the patient's sera is the most direct way to address the diagnosis of botulism. Based on previous published reports, botulinum toxemia was identified in about 70% of food-borne and wound botulism cases, and only in about 28% of infant botulism cases, in which the diagnosis is mainly confirmed from stool sample investigation. The presence of BoNT in serum depends on the BoNT amount ingested with contaminated food or produced locally in the intestine or wound, and the timeframe between serum sampling and disease onset. BoNT levels in patient's sera are most frequently low, requiring a highly sensitive method of detection. Mouse bioassay is still the most used method of botulism identification from serum samples. However, in vitro methods based on BoNT endopeptidase activity with detection by mass spectrometry or immunoassay have been developed and depending on BoNT type, are more sensitive than the mouse bioassay. These new assays show high specificity for individual BoNT types and allow more accurate differentiation between positive toxin sera from botulism and autoimmune neuropathy patients.
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17
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Wang Y, Schill KM, Fry HC, Duncan TV. A Quantum Dot Nanobiosensor for Rapid Detection of Botulinum Neurotoxin Serotype E. ACS Sens 2020; 5:2118-2127. [PMID: 32527082 DOI: 10.1021/acssensors.0c00738] [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: 01/29/2023]
Abstract
Botulinum neurotoxins (BoNTs) are potent toxins produced by Clostridium bacteria that are responsible for the illness botulism and are listed as bioterrorism agents. BoNT serotype E (BoNT/E) is one of four BoNT serotypes that cause human botulism and is the second most frequent cause of foodborne botulism. Rapid detection and discrimination of BoNT serotypes implicated in human disease are critical for ensuring timely treatment of patients and identifying sources of toxins, but there have been few reported detection methods for BoNT/E and even fewer methods usable for BoNT serotyping. We report a nanobiosensor based on Förster resonance energy transfer (FRET) between semiconductor nanocrystals (quantum dots, QDs) and dark quencher-labeled peptide probes to detect biologically active BoNT/E in aqueous media. The peptide probes contain a specific cleavage site for active BoNT/E. QD photoluminescence, which changes intensity due to FRET when the peptide probe is cleaved, was used to indicate toxin presence and quantity. The detection of a BoNT/E light chain (LcE) and holotoxin was observed within 3 h. The limits of detection were 0.02 and 2 ng/mL for LcE and holotoxin, respectively. The nanobiosensor shows good specificity toward the target in tests with nontarget BoNT serotypes. The high sensitivity, simple operation, short detection time, and ability to be used in parallel with probes developed for other BoNT serotypes indicate that the nanobiosensor will be useful for rapid BoNT/E detection and serotype discrimination in food analysis.
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Affiliation(s)
- Yun Wang
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Bedford Park, Illinois 60501, United States
| | - Kristin M. Schill
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Bedford Park, Illinois 60501, United States
| | - H. Christopher Fry
- Center for Nanoscale Materials, Argonne National Laboratory, DuPage County, Illinois 60439, United States
| | - Timothy V. Duncan
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Bedford Park, Illinois 60501, United States
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18
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Nepal MR, Jeong TC. Alternative Methods for Testing Botulinum Toxin: Current Status and Future Perspectives. Biomol Ther (Seoul) 2020; 28:302-310. [PMID: 32126735 PMCID: PMC7327137 DOI: 10.4062/biomolther.2019.200] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/06/2020] [Accepted: 02/17/2020] [Indexed: 01/29/2023] Open
Abstract
Botulinum toxins are neurotoxic modular proteins composed of a heavy chain and a light chain connected by a disulfide bond and are produced by Clostridium botulinum. Although lethally toxic, botulinum toxin in low doses is clinically effective in numerous medical conditions, including muscle spasticity, strabismus, hyperactive urinary bladder, excessive sweating, and migraine. Globally, several companies are now producing products containing botulinum toxin for medical and cosmetic purposes, including the reduction of facial wrinkles. To test the efficacy and toxicity of botulinum toxin, animal tests have been solely and widely used, resulting in the inevitable sacrifice of hundreds of animals. Hence, alternative methods are urgently required to replace animals in botulinum toxin testing. Here, the various alternative methods developed to test the toxicity and efficacy of botulinum toxins have been briefly reviewed and future perspectives have been detailed.
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Affiliation(s)
- Mahesh Raj Nepal
- College of Pharmacy, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Tae Cheon Jeong
- College of Pharmacy, Yeungnam University, Gyeongsan 38541, Republic of Korea
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19
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Schenke M, Schjeide BM, Püschel GP, Seeger B. Analysis of Motor Neurons Differentiated from Human Induced Pluripotent Stem Cells for the Use in Cell-Based Botulinum Neurotoxin Activity Assays. Toxins (Basel) 2020; 12:toxins12050276. [PMID: 32344847 PMCID: PMC7291138 DOI: 10.3390/toxins12050276] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/12/2020] [Accepted: 04/23/2020] [Indexed: 01/03/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) are potent neurotoxins produced by bacteria, which inhibit neurotransmitter release, specifically in their physiological target known as motor neurons (MNs). For the potency assessment of BoNTs produced for treatment in traditional and aesthetic medicine, the mouse lethality assay is still used by the majority of manufacturers, which is ethically questionable in terms of the 3Rs principle. In this study, MNs were differentiated from human induced pluripotent stem cells based on three published protocols. The resulting cell populations were analyzed for their MN yield and their suitability for the potency assessment of BoNTs. MNs produce specific gangliosides and synaptic proteins, which are bound by BoNTs in order to be taken up by receptor-mediated endocytosis, which is followed by cleavage of specific soluble N-ethylmaleimide-sensitive-factor attachment receptor (SNARE) proteins required for neurotransmitter release. The presence of receptors and substrates for all BoNT serotypes was demonstrated in MNs generated in vitro. In particular, the MN differentiation protocol based on Du et al. yielded high numbers of MNs in a short amount of time with high expression of BoNT receptors and targets. The resulting cells are more sensitive to BoNT/A1 than the commonly used neuroblastoma cell line SiMa. MNs are, therefore, an ideal tool for being combined with already established detection methods.
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Affiliation(s)
- Maren Schenke
- Institute for Food Toxicology, Department of Food Toxicology and Replacement/Complementary Methods to Animal Testing, University of Veterinary Medicine, 30173 Hannover, Germany;
| | - Brit-Maren Schjeide
- Institute of Nutritional Science, Department of Nutritional Biochemistry, University of Potsdam, 14558 Nuthetal, Germany; (B.-M.S.); (G.P.P.)
| | - Gerhard P. Püschel
- Institute of Nutritional Science, Department of Nutritional Biochemistry, University of Potsdam, 14558 Nuthetal, Germany; (B.-M.S.); (G.P.P.)
| | - Bettina Seeger
- Institute for Food Toxicology, Department of Food Toxicology and Replacement/Complementary Methods to Animal Testing, University of Veterinary Medicine, 30173 Hannover, Germany;
- Correspondence:
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20
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von Berg L, Stern D, Weisemann J, Rummel A, Dorner MB, Dorner BG. Optimization of SNAP-25 and VAMP-2 Cleavage by Botulinum Neurotoxin Serotypes A-F Employing Taguchi Design-of-Experiments. Toxins (Basel) 2019; 11:toxins11100588. [PMID: 31614566 PMCID: PMC6832249 DOI: 10.3390/toxins11100588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/01/2019] [Accepted: 10/09/2019] [Indexed: 11/17/2022] Open
Abstract
The detection of catalytically active botulinum neurotoxins (BoNTs) can be achieved by monitoring the enzymatic cleavage of soluble NSF (N-ethylmaleimide-sensitive-factor) attachment protein receptor (SNARE) proteins by the toxins’ light chains (LC) in cleavage-based assays. Thus, for sensitive BoNT detection, optimal cleavage conditions for the clinically relevant A–F serotypes are required. Until now, a systematic evaluation of cleavage conditions for the different BoNT serotypes is still lacking. To address this issue, we optimized cleavage conditions for BoNT/A–F using the Taguchi design-of-experiments (DoE) method. To this aim, we analyzed the influence of buffer composition (pH, Zn2+, DTT (dithiothreitol), NaCl) as well as frequently used additives (BSA (bovine serum albumin), Tween 20, trimethylamine N-oxide (TMAO)) on BoNT substrate cleavage. We identified major critical factors (DTT, Zn2+, TMAO) and were able to increase the catalytic efficiency of BoNT/B, C, E, and F when compared to previously described buffers. Moreover, we designed a single consensus buffer for the optimal cleavage of all tested serotypes. Our optimized buffers are instrumental to increase the sensitivity of cleavage-based assays for BoNT detection. Furthermore, the application of the Taguchi DoE approach shows how the method helps to rationally improve enzymatic assays.
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Affiliation(s)
- Laura von Berg
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Daniel Stern
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Jasmin Weisemann
- Institut für Toxikologie, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Martin Bernhard Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Brigitte Gertrud Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
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21
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Weingart OG, Eyer K, Lüchtenborg C, Sachsenheimer T, Brügger B, van Oostrum M, Wollscheid B, Dittrich PS, Loessner MJ. In vitro quantification of botulinum neurotoxin type A1 using immobilized nerve cell-mimicking nanoreactors in a microfluidic platform. Analyst 2019; 144:5755-5765. [PMID: 31433410 DOI: 10.1039/c9an00817a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The bacterial toxin botulinum neurotoxin A (BoNT/A) is not only an extremely toxic substance but also a potent pharmaceutical compound that is used in a wide spectrum of neurological disorders and cosmetic applications. The quantification of the toxin is extremely challenging due to its extraordinary high physiological potency and is further complicated by the toxin's three key functionalities that are necessary for its activity: receptor binding, internalization-translocation, and catalytic activity. So far, the industrial standard to measure the active toxin has been the mouse bioassay (MBA) that is considered today as outdated due to ethical issues. Therefore, recent introductions of cell-based assays were highly anticipated; their impact however remains limited due to their labor-intensive implementation. This report describes a new in vitro approach that combines a nanosensor based on the use of nerve cell-mimicking nanoreactors (NMN) with microfluidic technology. The nanosensor was able to measure all three key functionalities, and therefore suitable to quantify the amount of physiologically active BoNT/A. The integration of such a sensor in a microfluidic device allowed the detection and quantification of BoNT/A amounts in a much shorter time than the MBA (<10 h vs. 2-4 days). Lastly, the system was also able to reliably quantify physiologically active BoNT/A within a simple final pharmaceutical formulation. This complete in vitro testing system and its unique combination of a highly sensitive nanosensor and microfluidic technology represent a significant ethical advancement over in vivo measures and a possible alternative to cell-based in vitro detection methods.
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Affiliation(s)
- Oliver G Weingart
- Institute for Food, Nutrition and Health, ETH Zürich, Zurich, Switzerland
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