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Wu WQ, Li K, Chu LL, Shen TT, Li Y, Xu YY, Zhang QL, Liu CF, Liu J, Zhou XP, Luo WF. Association analyses between the variants of SNAP25, SV2C and ST3GAL2 and the efficacy of botulinum toxin A in the treatment of the primary Meige syndrome. Heliyon 2024; 10:e28543. [PMID: 38628704 PMCID: PMC11019161 DOI: 10.1016/j.heliyon.2024.e28543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 03/20/2024] [Accepted: 03/20/2024] [Indexed: 04/19/2024] Open
Abstract
Objective Individual differences were observed in the clinical efficacy of Botulinum toxin A (BoNT-A) in the treatment of the primary Meige syndrome. Our study aimed to explore the potential associations between the clinical efficacy of BoNT-A in the treatment of the primary Meige syndrome and variants of SNAP25, SV2C and ST3GAL2, which are involving in the translocation of the BoNT-A in vivo. Methods Patients with the primary Meige syndrome treated with BoNT-A were enrolled. Clinical efficacy was evaluated by the maximum improvement rate of motor symptoms and the duration of efficacy. Variants of SNAP25, SV2C and ST3GAL2 were obtained by Sanger sequencing. Another cohort diagnosed with primary cervical dystonia was also enrolled in the replication stage. Results Among the 104 primary Meige syndrome patients, 80 patients (76.9%) had a good efficacy (the maximum improvement rate of motor symptoms ≥30%) and 24 (23. 1%) had a poor (the maximum improvement rate of motor symptoms <30%). As to the duration of efficacy, 52 patients (50.0%) had a long duration of efficacy (≥4 months), and 52 (50.0%) had a short (<4 months). In terms of primary Meige syndrome, SNAP25 rs6104571 was found associating with the maximum improvement rate of motor symptoms (Genotype: P = 0.02, OR = 0.26; Allele: P = 0.013, OR = 0.29), and SV2C rs31244 was found associating with the duration of efficacy (Genotype: P = 0.024, OR = 0.13; Allele: P = 0.012, OR = 0.13). Besides, we also conducted the association analyses between the variants and BoNT-A-related adverse reactions. Although, there was no statistical difference between the allele of SV2C rs31244 and BoNT-A-related adverse reactions, there was a trend (P = 0.077, OR = 2.56). In the replication stage, we included 39 patients with primary cervical dystonia to further expanding the samples' size. Among the 39 primary cervical dystonia patients, 25 patients (64.1%) had a good efficacy (the maximum improvement rate of motor symptoms ≥50%) and 14 (35.9%) had a poor (the maximum improvement rate of motor symptoms <50%). As to the duration of efficacy, 32 patients (82.1%) had a long duration of efficacy (≥6 months), and 7 (17.9%) had a short (<6 months). Integrating primary Meige syndrome and primary cervical dystonia, SV2C rs31244 was still found associating with the duration of efficacy (Genotype: P = 0.002, OR = 0. 23; Allele: P = 0.001, OR = 0. 25). Conclusion In our study, SNAP25 rs6104571 was associated with the maximum improvement rate of motor symptoms in patients with primary Meige syndrome treated with BoNT-A, and patients carrying this variant had a lower improvement rate of motor symptoms. SV2C rs31244 was associated with duration of treatment in patients with primary Meige syndrome treated with BoNT-A and patients carrying this variant had a shorter duration of treatment. Patients with primary Meige syndrome carrying SV2C rs31244 G allele have an increase likelihood of BoNT-A-related adverse reactions. Involving 39 patients with primary cervical dystonia, the results further verify that SV2C rs31244 was associated with duration of treatment and patients carrying this variant had a shorter duration of treatment.
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Affiliation(s)
- Wen-Qi Wu
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
- Department of Neurology, Affiliated Hospital of Jiangsu University, Zhenjiang, 212000, Jiangsu, China
| | - Kai Li
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
| | - Lu-Lu Chu
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
| | - Ting-Ting Shen
- Department of Neurology, The Second Affiliated Hospital of Jiaxing University, Jiaxing, 314000, Zhejiang, China
| | - Yang Li
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
- Department of Neurology, Huzhou Central Hospital, Affiliated Central Hospital Huzhou University, Huzhou, 313000, Zhejiang, China
| | - Ying-Ying Xu
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
| | - Qi-Lin Zhang
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
| | - Chun-Feng Liu
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
| | - Jing Liu
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
| | - Xu-Ping Zhou
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
| | - Wei-Feng Luo
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, China
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Gregory KS, Hall PR, Onuh JP, Mojanaga OO, Liu SM, Acharya KR. Crystal Structure of the Catalytic Domain of a Botulinum Neurotoxin Homologue from Enterococcus faecium: Potential Insights into Substrate Recognition. Int J Mol Sci 2023; 24:12721. [PMID: 37628902 PMCID: PMC10454453 DOI: 10.3390/ijms241612721] [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: 06/28/2023] [Revised: 07/25/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Clostridium botulinum neurotoxins (BoNTs) are the most potent toxins known, causing the deadly disease botulism. They function through Zn2+-dependent endopeptidase cleavage of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins, preventing vesicular fusion and subsequent neurotransmitter release from motor neurons. Several serotypes of BoNTs produced by Clostridium botulinum (BoNT/A-/G and/X) have been well-characterised over the years. However, a BoNT-like gene (homologue of BoNT) was recently identified in the non-clostridial species, Enterococcus faecium, which is the leading cause of hospital-acquired multi-drug resistant infections. Here, we report the crystal structure of the catalytic domain of a BoNT homologue from Enterococcus faecium (LC/En) at 2.0 Å resolution. Detailed structural analysis in comparison with the full-length BoNT/En AlphaFold2-predicted structure, LC/A (from BoNT/A), and LC/F (from BoNT/F) revealed putative subsites and exosites (including loops 1-5) involved in recognition of LC/En substrates. LC/En also appears to possess a conserved autoproteolytic cleavage site whose function is yet to be established.
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Affiliation(s)
- Kyle S. Gregory
- Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK; (K.S.G.); (P.-R.H.); (J.P.O.); (O.O.M.)
| | - Peter-Rory Hall
- Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK; (K.S.G.); (P.-R.H.); (J.P.O.); (O.O.M.)
| | - Jude Prince Onuh
- Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK; (K.S.G.); (P.-R.H.); (J.P.O.); (O.O.M.)
| | - Otsile O. Mojanaga
- Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK; (K.S.G.); (P.-R.H.); (J.P.O.); (O.O.M.)
| | - Sai Man Liu
- Protein Sciences Department, Ipsen Bioinnovation Limited, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK;
| | - K. Ravi Acharya
- Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK; (K.S.G.); (P.-R.H.); (J.P.O.); (O.O.M.)
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Li Y, Chen Y, Cui J, Liu D, Zhang W, Xue C, Xiong X, Liu G, Chen H. Preparation and characterization of a neutralizing murine monoclonal antibody against tetanus toxin. J Immunol Methods 2023; 513:113427. [PMID: 36652969 DOI: 10.1016/j.jim.2023.113427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/11/2022] [Accepted: 01/11/2023] [Indexed: 01/16/2023]
Abstract
After Clostridium tetani infects the human body, it propagates under anaerobic conditions and produces tetanus neurotoxin (TeNT). TeNT can affect the central nervous system, inhibit the release of neurotransmitters, and result in respiratory failure, which are the root causes of death in tetanus patients. Identifying monoclonal antibodies (mAbs) targeting TeNT with neutralizing activity is urgently needed for the prevention and treatment of tetanus infection. In this study, through immunizing BALB/c mice with tetanus toxoid (TT), we obtained six positive hybridoma cell lines (1A7, 2C7, 3A7, 3H4, 4C1, and 4E12). Antibody isotyping showed that the antibodies are all of the IgG1/κ subclass. Ascites fluid was prepared by allogeneic ascites induction and the antibodies were purified through protein G affinity chromatography columns. Purities of the produced murine mAbs were all greater than 95%. All six antibodies bound to linear epitopes, among which 3A7 bound to the TeNT/L domain and the other five antibodies bound to the TeNT/Hc domain. Moreover, the affinity constants of these six antibodies against the antigen were all in the nanomolar range, and the affinity of 4E12 antibody reached the picomolar range. Results from toxin-neutralization assays in mice showed that 2C7 antibody delayed animal death, while 1A7, 3A7, 3H4, and 4E12 antibodies conferred partial protection. Additionally, 4C1 antibody offered complete protection, as 200 μg of 4C1 antibody fully protected against toxin challenge with 10 LD50 of TeNT and had a window period of 1 h. Antibody epitope grouping results revealed that the binding epitopes of 4C1 antibody were different from those of the other five antibodies. When 4C1 antibody was used in combination with another antibody, the neutralizing activities of antibodies were all evidently enhanced. Specifically, 4C1 combined with 3A7 antibody led to the greatest improvement in neutralizing activities, and 20 μg antibodies total (10 + 10 μg) fully protected against toxin challenge with 10 LD50. When 4E12, 3A7, and 4C1 antibodies were used in combination, 18 μg antibodies total (6 + 6 + 6 μg) completely neutralized 10 LD50 toxin. The present study derived murine mAbs with neutralizing activities and laid the foundation for follow-up therapeutic drug development for TeNT poisoning as well as establishment of TeNT detection methods.
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Affiliation(s)
- Yi Li
- Academy of Military Medical Sciences, Beijing 100080, China
| | - Yangyang Chen
- College of Pharmacy, Harbin University of Commerce, Harbin 1500076, China
| | - Jiazhen Cui
- Academy of Military Medical Sciences, Beijing 100080, China
| | - Dongqi Liu
- College of Pharmacy, Harbin University of Commerce, Harbin 1500076, China
| | - Weicai Zhang
- Academy of Military Medical Sciences, Beijing 100080, China
| | - Chong Xue
- Academy of Military Medical Sciences, Beijing 100080, China
| | - Xianghua Xiong
- Academy of Military Medical Sciences, Beijing 100080, China.
| | - Gang Liu
- Academy of Military Medical Sciences, Beijing 100080, China.
| | - Huipeng Chen
- Academy of Military Medical Sciences, Beijing 100080, China.
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Structure and activity of botulinum neurotoxin X. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.11.523524. [PMID: 36712025 PMCID: PMC9882044 DOI: 10.1101/2023.01.11.523524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins known and are used to treat an increasing number of medical disorders. All BoNTs are naturally co-expressed with a protective partner protein (NTNH) with which they form a 300 kDa complex, to resist acidic and proteolytic attack from the digestive tract. We have previously identified a new botulinum neurotoxin serotype, BoNT/X, that has unique and therapeutically attractive properties. We present the cryo-EM structure of the BoNT/X-NTNH/X complex at 3.1 Å resolution. Unexpectedly, the BoNT/X complex is stable and protease resistant at both neutral and acidic pH and disassembles only in alkaline conditions. Using the stabilizing effect of NTNH, we isolated BoNT/X and showed that it has very low potency both in vitro and in vivo . Given the high catalytic activity and translocation efficacy of BoNT/X, low activity of the full toxin is likely due to the receptor-binding domain, which presents weak ganglioside binding and exposed hydrophobic surfaces.
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Abstract
AB toxins are protein virulence factors secreted by many bacterial pathogens, contributing to the pathogenicity of the cognate bacteria. AB toxins consist of two functionally distinct components: the enzymatic "A" component for pathogenicity and the receptor-binding "B" component for toxin delivery. Consistently, unlike other virulence factors such as effectors, AB toxins do not require additional systems to deliver them to the target host cells. Target host cells are located in the infection site and/or located distantly from infected host cells. The first part of this review discusses the structural and functional features of single-peptide and multiprotein AB toxins in the context of host-microbe interactions, using several well-characterized examples. The second part of this review discusses toxin neutralization strategies, as well as applications of AB toxins relevant to developing intervention strategies against diseases.
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6
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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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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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Zhang G, Yu R, Chi X, Chen Z, Hao M, Du P, Fan P, Liu Y, Dong Y, Fang T, Chen Y, Song X, Liu S, Li J, Yu C, Chen W. Tetanus vaccine-induced human neutralizing antibodies provide full protection against neurotoxin challenge in mice. Int Immunopharmacol 2021; 91:107297. [PMID: 33360088 DOI: 10.1016/j.intimp.2020.107297] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/10/2020] [Accepted: 12/10/2020] [Indexed: 10/22/2022]
Abstract
Clostridium tetani causes life-threatening disease by producing tetanus neurotoxin (TeNT), one of the most toxic protein substances. Toxicosis can be prevented and cured by administration of anti-TeNT neutralizing antibodies. Here, we identified a series of monoclonal antibodies (mAbs) derived from memory B cells of a healthy adult immunized with the C-terminal domain of TeNT (TeNT-Hc). Thirteen mAbs bound to both tetanus toxoid (TT) and TeNT-Hc, while two mAbs recognized only TT. VH3-23 was the most frequently used germline gene in these TT-binding mAbs, and the pairwise identity values of the VH gene sequences ranged from 27% to 69%. Three of these mAbs-T3, T7, and T9-6-completely protected mice from challenge with 2× LD50 of TeNT, and two (T2 and T18) significantly prolonged the survival time. The five neutralizing mAbs recognized distinct epitopes on TT, with binding affinities ranging from 0.123 to 11.9 nM. Our study provides promising therapeutic candidates for tetanus.
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Affiliation(s)
- Guanying Zhang
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Rui Yu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Xiangyang Chi
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Zhengshan Chen
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Meng Hao
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Peng Du
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Pengfei Fan
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Yujiao Liu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Yunzhu Dong
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Ting Fang
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Yi Chen
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Xiaohong Song
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Shuling Liu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Jianmin Li
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Changming Yu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Wei Chen
- Beijing Institute of Biotechnology, Beijing 100071, China.
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Liu FJ, Shi DY, Li ZY, Lu JS, Wang R, Pang XB, Yang ZX, Yu YZ. Evaluation of a recombinant tetanus toxin subunit vaccine. Toxicon 2020; 187:75-81. [PMID: 32889026 DOI: 10.1016/j.toxicon.2020.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/30/2020] [Accepted: 08/03/2020] [Indexed: 10/23/2022]
Abstract
Tetanus is an acute, fatal disease caused by exotoxin produced by Clostridium tetani. The current vaccine against tetanus is based on inactivated tetanus toxin (TeNT). To develop a recombinant TeNT vaccine suitable for replacement of full-length tetanus toxoid (TT) vaccine for use in humans, a recombinant non-tagged isoform of the Hc domain of the tetanus toxin (THc) was expressed in Escherichia coli and purified by sequential chromatography steps. The immunogenicity and protective effect of the THc antigen were explored and compared with those of TT in Balb/c mice. The THc-based subunit vaccine provided complete protection against TeNT challenge following a high dosage as a toxoid vaccine. While the anti-THc and neutralising antibody titres were higher for the THc-based vaccine than the TT vaccine because protective epitopes are located on the THc domain. Frequency- and dose-dependent immunoprotection were also observed in THc-immunised mice. Mice immunised with one injection of 1 μg or 4 μg THc antigen were completely protected against 102 or 103 50% mouse lethal dose (LD50) of TeNT, respectively. Furthermore, the THc protein was found to recognise and bind to ganglioside GT1b in a dose-dependent manner, and anti-THc sera antibodies also inhibited binding between THc and GT1b. Antigen on the form of recombinant non-tagged THc domain expressed in E. coli achieved strong immunoprotective potency, suggesting that it could be developed into a candidate subunit vaccine against tetanus as an alternative to the current TT vaccine.
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Affiliation(s)
- Fu-Jia Liu
- Beijing Institute of Biotechnology, Beijing, 100071, China; Pharmaceutical College, Henan University, Kaifeng, 475001, China
| | - Dan-Yang Shi
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Zhi-Ying Li
- Beijing Institute of Biotechnology, Beijing, 100071, China; Pharmaceutical College, Henan University, Kaifeng, 475001, China
| | - Jian-Sheng Lu
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Rong Wang
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Xiao-Bin Pang
- Pharmaceutical College, Henan University, Kaifeng, 475001, China.
| | - Zhi-Xin Yang
- Beijing Institute of Biotechnology, Beijing, 100071, China.
| | - Yun-Zhou Yu
- Beijing Institute of Biotechnology, Beijing, 100071, China.
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Immunological characterisation and immunoprotective efficacy of functional domain antigens of botulinum neurotoxin serotype A. Vaccine 2020; 38:2978-2983. [PMID: 32113807 DOI: 10.1016/j.vaccine.2020.02.060] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/11/2020] [Accepted: 02/18/2020] [Indexed: 12/20/2022]
Abstract
Botulinum neurotoxins (BoNTs) are highly toxic proteins that mediate their effects by binding to neuronal receptors and block the neutralizing ability of therapeutic antibodies. Vaccination is currently the most effective strategy to prevent botulism. In this study, a series of recombinant functional domain antigens of BoNT/A were prepared and identified, and their immunoprotective efficacies were explored and compared. Our results showed that all antigens produced strong humoral immune responses, although their protective effects against the toxin were different. Only the Hc and HN-L antigens produced strong protective effects and afforded complete immunoprotection. In addition, the combined vaccine groups showed that there was no synergistic effect on immune responses after antigen combination, suggesting that the integrity of the toxin antigen or domain is crucial to the immune effects. Studies of the dose-dependent immunoprotective effects further confirmed that the Hc domain antigen afforded more effective protective potency than the HN-L antigen, equivalent to the immune effect of the full-length toxin (Hc + HN-L combination group). Overall, our results demonstrated that the Hc domain elicited a strong protective immune response and also provided basic data and theoretical support for the development of Hc-based BoNT/A subunit vaccine. Therefore, the receptor binding domain Hc is implicated as a promising target antigen of the BoNT/A recombinant subunit vaccine as an alternative to the toxoid vaccine.
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11
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Poulain B, Lemichez E, Popoff MR. Neuronal selectivity of botulinum neurotoxins. Toxicon 2020; 178:20-32. [PMID: 32094099 DOI: 10.1016/j.toxicon.2020.02.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 02/03/2020] [Accepted: 02/10/2020] [Indexed: 12/12/2022]
Abstract
Botulinum neurotoxins (BoNTs) are highly potent toxins responsible for a severe disease, called botulism. They are also efficient therapeutic tools with an increasing number of indications ranging from neuromuscular dysfunction to hypersecretion syndrome, pain release, depression as well as cosmetic application. BoNTs are known to mainly target the motor-neurons terminals and to induce flaccid paralysis. BoNTs recognize a specific double receptor on neuronal cells consisting of gangliosides and synaptic vesicle protein, SV2 or synaptotagmin. Using cultured neuronal cells, BoNTs have been established blocking the release of a wide variety of neurotransmitters. However, BoNTs are more potent in motor-neurons than in the other neuronal cell types. In in vivo models, BoNT/A impairs the cholinergic neuronal transmission at the motor-neurons but also at neurons controlling secretions and smooth muscle neurons, and blocks several neuronal pathways including excitatory, inhibitory, and sensitive neurons. However, only a few reports investigated the neuronal selectivity of BoNTs in vivo. In the intestinal wall, BoNT/A and BoNT/B target mainly the cholinergic neurons and to a lower extent the other non-cholinergic neurons including serotonergic, glutamatergic, GABAergic, and VIP-neurons. The in vivo effects induced by BoNTs on the non-cholinergic neurons remain to be precisely investigated. We report here a literature review of the neuronal selectivity of BoNTs.
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Affiliation(s)
- Bernard Poulain
- Université de Strasbourg, CNRS, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
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12
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Rossetto O, Pirazzini M, Fabris F, Montecucco C. Botulinum Neurotoxins: Mechanism of Action. Handb Exp Pharmacol 2020; 263:35-47. [PMID: 32277300 DOI: 10.1007/164_2020_355] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Botulinum neurotoxins (BoNTs) are a growing family of bacterial protein toxins that cause botulism, a rare but often fatal animal and human disease. They are the most potent toxins known owing to their molecular architecture, which underlies their mechanism of action. BoNTs target peripheral nerve terminals by a unique mode of binding and enter into their cytosol where they cleave SNARE proteins, thus inhibiting the neurotransmitter release. The specificity and rapidity of binding, which limits the anatomical area of its neuroparalytic action, and its reversible action make BoNT a valuable pharmaceutical to treat neurological and non-neurological diseases determined by hyperactivity of cholinergic nerve terminals. This review reports the progress on our understanding of how BoNTs cause nerve paralysis highlighting the different steps of their molecular mechanism of action as key aspects to explain their extreme toxicity but also their unique pharmacological properties.
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Affiliation(s)
- O Rossetto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - M Pirazzini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - F Fabris
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - C Montecucco
- Department of Biomedical Sciences, University of Padova, Padova, Italy. .,Institute of Neuroscience, National Research Council, Padova, Italy.
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13
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Pellett S, Tepp WH, Johnson EA. Critical Analysis of Neuronal Cell and the Mouse Bioassay for Detection of Botulinum Neurotoxins. Toxins (Basel) 2019; 11:toxins11120713. [PMID: 31817843 PMCID: PMC6950160 DOI: 10.3390/toxins11120713] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/12/2019] [Accepted: 11/22/2019] [Indexed: 12/14/2022] Open
Abstract
Botulinum Neurotoxins (BoNTs) are a large protein family that includes the most potent neurotoxins known to humankind. BoNTs delivered locally in humans at low doses are widely used pharmaceuticals. Reliable and quantitative detection of BoNTs is of paramount importance for the clinical diagnosis of botulism, basic research, drug development, potency determination, and detection in clinical, environmental, and food samples. Ideally, a definitive assay for BoNT should reflect the activity of each of the four steps in nerve intoxication. The in vivo mouse bioassay (MBA) is the ‘gold standard’ for the detection of BoNTs. The MBA is sensitive, robust, semi-quantitative, and reliable within its sensitivity limits. Potential drawbacks with the MBA include assay-to-assay potency variations, especially between laboratories, and false positives or negatives. These limitations can be largely avoided by careful planning and performance. Another detection method that has gained importance in recent years for research and potency determination of pharmaceutical BoNTs is cell-based assays, as these assays can be highly sensitive, quantitative, human-specific, and detect fully functional holotoxins at physiologically relevant concentrations. A myriad of other in vitro BoNT detection methods exist. This review focuses on critical factors and assay limitations of the mouse bioassay and cell-based assays for BoNT detection.
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14
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Ückert S, Kedia GT, Tsikas D, Simon A, Bannowsky A, Kuczyk MA. Emerging drugs to target lower urinary tract symptomatology (LUTS)/benign prostatic hyperplasia (BPH): focus on the prostate. World J Urol 2019; 38:1423-1435. [PMID: 31506747 DOI: 10.1007/s00345-019-02933-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 08/28/2019] [Indexed: 01/07/2023] Open
Abstract
OBJECTIVES The benign prostatic syndrome, comprising lower urinary tract symptomatology secondary to benign prostatic hyperplasia/enlargement, represents a major health care issue in westernized countries. The pharmacological management involves alpha-adrenoceptor antagonists, intervention into the hormonal control of prostate growth using inhibitors of the enzyme 5-alpha-reductase, and stimulation of the nitric oxide/cyclic GMP pathway by tadalafil, an inhibitor of the phosphodiesterase type 5. METHODS This review summarizes the achievements which have been made in the development of drug candidates assumed to offer opportunities as beneficial treatment options in the management of the benign prostatic syndrome. RESULTS A review of the literature has revealed that the line of development is focusing on drugs interfering with peripheral neuromuscular/neuronal mechanisms (nitric oxide donor drugs, agonists/antagonists of endogenous peptides, botulinum toxin, NX-1207), the steroidal axis (cetrorelix) or the metabolic turn-over (lonidamine), as well as the combination of drugs already established in the treatment of lower urinary tract symptomatology/benign prostatic hyperplasia (phosphodiesterase 5 inhibitor plus alpha-adrenoceptor antagonist). CONCLUSION Many research efforts have provided the basis for the development of new therapeutic modalities for the management of lower urinary tract dysfunctions, some of which might be offered to the patients in the near future.
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Affiliation(s)
- Stefan Ückert
- Division of Surgery, Department of Urology and Urological Oncology, Hannover Medical School, 30623, Hannover, Germany.
| | - George T Kedia
- Division of Surgery, Department of Urology and Urological Oncology, Hannover Medical School, 30623, Hannover, Germany
| | - Dimitrios Tsikas
- Core Unit Proteomics, Center of Pharmacology and Toxicology, Hannover Medical School, Hannover, Germany
| | - Annika Simon
- Department of Internal Medicine, Hannover Medical School, Hannover, Germany
| | | | - Markus A Kuczyk
- Division of Surgery, Department of Urology and Urological Oncology, Hannover Medical School, 30623, Hannover, Germany
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15
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Contreras E, Masuyer G, Qureshi N, Chawla S, Dhillon HS, Lee HL, Chen J, Stenmark P, Gill SS. A neurotoxin that specifically targets Anopheles mosquitoes. Nat Commun 2019; 10:2869. [PMID: 31253776 PMCID: PMC6599013 DOI: 10.1038/s41467-019-10732-w] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 05/23/2019] [Indexed: 11/24/2022] Open
Abstract
Clostridial neurotoxins, including tetanus and botulinum neurotoxins, generally target vertebrates. We show here that this family of toxins has a much broader host spectrum, by identifying PMP1, a clostridial-like neurotoxin that selectively targets anopheline mosquitoes. Isolation of PMP1 from Paraclostridium bifermentans strains collected in anopheline endemic areas on two continents indicates it is widely distributed. The toxin likely evolved from an ancestral form that targets the nervous system of similar organisms, using a common mechanism that disrupts SNARE-mediated exocytosis. It cleaves the mosquito syntaxin and employs a unique receptor recognition strategy. Our research has an important impact on the study of the evolution of clostridial neurotoxins and provides the basis for the use of P. bifermentans strains and PMP1 as innovative, environmentally friendly approaches to reduce malaria through anopheline control. So far identified clostridial neurotoxins target vertebrates. Here, Contreras et al. isolate the clostridial-like neurotoxin PMP1 from Paraclostridium bifermentans strains and show that it selectively targets anopheline mosquitoes by targeting mosquito syntaxin.
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Affiliation(s)
- Estefania Contreras
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Nadia Qureshi
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Swati Chawla
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Harpal S Dhillon
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Han Lim Lee
- Unit of Medical Entomology, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Jianwu Chen
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden. .,Department of Experimental Medical Science, Lund University, Lund, 22100, Sweden.
| | - Sarjeet S Gill
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA.
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16
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Košenina S, Masuyer G, Zhang S, Dong M, Stenmark P. Crystal structure of the catalytic domain of the Weissella oryzae botulinum-like toxin. FEBS Lett 2019; 593:1403-1410. [PMID: 31111466 DOI: 10.1002/1873-3468.13446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 11/10/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins known. So far, eight serotypes have been identified that all act as zinc-dependent endopeptidases targeting SNARE proteins and inhibiting the release of neurotransmitters. Recently, the first botulinum toxin-like protein was identified outside the Clostridial genus, designated BoNT/Wo in the genome of Weissella oryzae. Here, we report the 1.6 Å X-ray crystal structure of the light chain of BoNT/Wo (LC/Wo). LC/Wo presents the core fold common to BoNTs but has an unusually wide, open and negatively charged catalytic pocket, with an additional Ca2+ ion besides the zinc ion and a unique ß-hairpin motif. The structural information will help establish the substrate profile of BoNT/Wo and help our understanding of how BoNT evolved.
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Affiliation(s)
- Sara Košenina
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | - Sicai Zhang
- Department of Urology, Boston Children's Hospital, Boston, MA, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Min Dong
- Department of Urology, Boston Children's Hospital, Boston, MA, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Sweden.,Department of Experimental Medical Science, Lund University, Sweden
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17
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18
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Abstract
Tetanus is a vaccine-preventable disease that still commonly occurs in many low-income and middle-income countries, although it is rare in high-income countries. The disease is caused by the toxin of the bacterium Clostridium tetani and is characterised by muscle spasms and autonomic nervous system dysfunction. Global vaccination initiatives have had considerable success but they continue to face many challenges. Treatment for tetanus aims to control spasms and reduce cardiovascular instability, and consists of wound debridement, antitoxin, antibiotics, and supportive care. Recent research has focused on intravenous magnesium sulphate and intrathecal antitoxin administration as methods of spasm control that can avoid the need for ventilatory support. Nevertheless, without access to mechanical ventilation, mortality from tetanus remains high. Even with such care, patients require several weeks of hospitalisation and are vulnerable to secondary problems, such as hospital-acquired infections.
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Affiliation(s)
- Lam Minh Yen
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - C Louise Thwaites
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam; Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
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19
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Structural characterisation of the catalytic domain of botulinum neurotoxin X - high activity and unique substrate specificity. Sci Rep 2018. [PMID: 29540745 PMCID: PMC5851995 DOI: 10.1038/s41598-018-22842-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are among the most potent toxins known and are also used to treat an increasing number of medical disorders. There are seven well-established serotypes (BoNT/A-G), which all act as zinc-dependent endopeptidases targeting specific members of the SNARE proteins required for synaptic vesicle exocytosis in neurons. A new toxin serotype, BoNT/X, was recently identified. It cleaves not only the canonical targets, vesicle associated membrane proteins (VAMP) 1/2/3 at a unique site, but also has the unique ability to cleave VAMP4/5 and Ykt6. Here we report the 1.35 Å X-ray crystal structure of the light chain of BoNT/X (LC/X). LC/X shares the core fold common to all other BoNTs, demonstrating that LC/X is a bona fide member of BoNT-LCs. We found that access to the catalytic pocket of LC/X is more restricted, and the regions lining the catalytic pocket are not conserved compared to other BoNTs. Kinetic studies revealed that LC/X cleaves VAMP1 with a ten times higher efficiency than BoNT/B and the tetanus neurotoxin. The structural information provides a molecular basis to understand the convergence/divergence between BoNT/X and other BoNTs, to develop effective LC inhibitors, and to engineer new scientific tools and therapeutic toxins targeting distinct SNARE proteins in cells.
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20
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Botulinum neurotoxin type C protease induces apoptosis in differentiated human neuroblastoma cells. Oncotarget 2017; 7:33220-8. [PMID: 27121208 PMCID: PMC5078088 DOI: 10.18632/oncotarget.8903] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/04/2016] [Indexed: 12/31/2022] Open
Abstract
Neuroblastomas constitute a major cause of cancer-related deaths in young children. In recent years, a number of translation-inhibiting enzymes have been evaluated for killing neuroblastoma cells. Here we investigated the potential vulnerability of human neuroblastoma cells to protease activity derived from botulinum neurotoxin type C. We show that following retinoic acid treatment, human neuroblastoma cells, SiMa and SH-SY5Y, acquire a neuronal phenotype evidenced by axonal growth and expression of neuronal markers. Botulinum neurotoxin type C which cleaves neuron-specific SNAP25 and syntaxin1 caused apoptotic death only in differentiated neuroblastoma cells. Direct comparison of translation-inhibiting enzymes and the type C botulinum protease revealed one order higher cytotoxic potency of the latter suggesting a novel neuroblastoma-targeting pathway. Our mechanistic insights revealed that loss of ubiquitous SNAP23 due to differentiation coupled to SNAP25 cleavage due to botulinum activity may underlie the apoptotic death of human neuroblastoma cells.
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21
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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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22
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Connan C, Popoff MR. Uptake of Clostridial Neurotoxins into Cells and Dissemination. Curr Top Microbiol Immunol 2017; 406:39-78. [PMID: 28879524 DOI: 10.1007/82_2017_50] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Clostridial neurotoxins, botulinum neurotoxins (BoNT) and tetanus neurotoxin (TeNT), are potent toxins, which are responsible for severe neurological diseases in man and animals. BoNTs induce a flaccid paralysis (botulism) by inhibiting acetylcholine release at the neuromuscular junctions, whereas TeNT causes a spastic paralysis (tetanus) by blocking the neurotransmitter release (glycine, GABA) in inhibitory interneurons within the central nervous system. Clostridial neurotoxins recognize specific receptor(s) on the target neuronal cells and enter via a receptor-mediated endocytosis. They transit through an acidic compartment which allows the translocation of the catalytic chain into the cytosol, a prerequisite step for the intracellular activity of the neurotoxins. TeNT migrates to the central nervous system by using a motor neuron as transport cell. TeNT enters a neutral pH compartment and undergoes a retrograde axonal transport to the spinal cord or brain, where the whole undissociated toxin is delivered and interacts with target neurons. Botulism most often results from ingestion of food contaminated with BoNT. Thus, BoNT passes through the intestinal epithelial barrier mainly via a transcytotic mechanism and then diffuses or is transported to the neuromuscular junctions by the lymph or blood circulation. Indeed, clostridial neurotoxins are specific neurotoxins which transit through a transport cell to gain access to the target neuron, and use distinct trafficking pathways in both cell types.
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Affiliation(s)
- Chloé Connan
- Unité Des Bactéries Anaérobies et Toxines, Institut Pasteur, 25 Rue Du Dr Roux, 75724, Paris Cedex 15, France
| | - Michel R Popoff
- Unité Des Bactéries Anaérobies et Toxines, Institut Pasteur, 25 Rue Du Dr Roux, 75724, Paris Cedex 15, France.
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23
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Hamark C, Berntsson RPA, Masuyer G, Henriksson LM, Gustafsson R, Stenmark P, Widmalm G. Glycans Confer Specificity to the Recognition of Ganglioside Receptors by Botulinum Neurotoxin A. J Am Chem Soc 2016; 139:218-230. [PMID: 27958736 DOI: 10.1021/jacs.6b09534] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The highly poisonous botulinum neurotoxins, produced by the bacterium Clostridium botulinum, act on their hosts by a high-affinity association to two receptors on neuronal cell surfaces as the first step of invasion. The glycan motifs of gangliosides serve as initial coreceptors for these protein complexes, whereby a membrane protein receptor is bound. Herein we set out to characterize the carbohydrate minimal binding epitope of the botulinum neurotoxin serotype A. By means of ligand-based NMR spectroscopy, X-ray crystallography, computer simulations, and isothermal titration calorimetry, a screening of ganglioside analogues together with a detailed characterization of various carbohydrate ligand complexes with the toxin were accomplished. We show that the representation of the glycan epitope to the protein affects the details of binding. Notably, both branches of the oligosaccharide GD1a can associate to botulinum neurotoxin serotype A when expressed as individual trisaccharides. It is, however, the terminal branch of GD1a as well as this trisaccharide motif alone, corresponding to the sialyl-Thomsen-Friedenreich antigen, that represents the active ligand epitope, and these compounds bind to the neurotoxin with a high degree of predisposition but with low affinities. This finding does not correlate with the oligosaccharide moieties having a strong contribution to the total affinity, which was expected to be the case. We here propose that the glycan part of the ganglioside receptors mainly provides abundance and specificity, whereas the interaction with the membrane itself and protein receptor brings about the strong total binding of the toxin to the neuronal membrane.
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Affiliation(s)
- Christoffer Hamark
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden
| | - Ronnie P-A Berntsson
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden
| | - Linda M Henriksson
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden
| | - Robert Gustafsson
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden
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24
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Moreira C, da Cunha CEP, Moreira GMSG, Mendonça M, Salvarani FM, Moreira ÂN, Conceição FR. Protective potential of recombinant non-purified botulinum neurotoxin serotypes C and D. Anaerobe 2016; 40:58-62. [DOI: 10.1016/j.anaerobe.2016.05.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/15/2016] [Accepted: 05/24/2016] [Indexed: 12/01/2022]
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25
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Genomic characterization of Italian Clostridium botulinum group I strains. INFECTION GENETICS AND EVOLUTION 2015; 36:62-71. [DOI: 10.1016/j.meegid.2015.08.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 08/27/2015] [Accepted: 08/31/2015] [Indexed: 02/07/2023]
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26
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Benoit RM, Frey D, Wieser MM, Thieltges KM, Jaussi R, Capitani G, Kammerer RA. Structure of the BoNT/A1--receptor complex. Toxicon 2015; 107:25-31. [PMID: 26260692 DOI: 10.1016/j.toxicon.2015.08.002] [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] [Received: 07/23/2015] [Accepted: 08/04/2015] [Indexed: 11/16/2022]
Abstract
Botulinum neurotoxin A causes botulism but is also used for medical and cosmetic applications. A detailed molecular understanding of BoNT/A--host receptor interactions is therefore fundamental for improving current clinical applications and for developing new medical strategies targeting human disorders. Towards this end, we recently solved an X-ray crystal structure of BoNT/A1 in complex with its neuronal protein receptor SV2C. Based on our findings, we discuss the potential implications for BoNT/A function.
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Affiliation(s)
- Roger M Benoit
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Daniel Frey
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Mara M Wieser
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Katherine M Thieltges
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Rolf Jaussi
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Guido Capitani
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Richard A Kammerer
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
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27
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Diamant E, Torgeman A, Ozeri E, Zichel R. Monoclonal Antibody Combinations that Present Synergistic Neutralizing Activity: A Platform for Next-Generation Anti-Toxin Drugs. Toxins (Basel) 2015; 7:1854-81. [PMID: 26035486 PMCID: PMC4488679 DOI: 10.3390/toxins7061854] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/07/2015] [Accepted: 05/19/2015] [Indexed: 12/25/2022] Open
Abstract
Monoclonal antibodies (MAbs) are among the fastest-growing therapeutics and are being developed for a broad range of indications, including the neutralization of toxins, bacteria and viruses. Nevertheless, MAbs potency is still relatively low when compared to conventional polyclonal Ab preparations. Moreover, the efficacy of an individual neutralizing MAb may significantly be hampered by the potential absence or modification of its target epitope in a mutant or subtype of the infectious agent. These limitations of individual neutralizing MAbs can be overcome by using oligoclonal combinations of several MAbs with different specificities to the target antigen. Studies conducted in our lab and by others show that such combined MAb preparation may present substantial synergy in its potency over the calculated additive potency of its individual MAb components. Moreover, oligoclonal preparation is expected to be better suited to compensating for reduced efficacy due to epitope variation. In this review, the synergistic neutralization properties of combined oligoclonal Ab preparations are described. The effect of Ab affinity, autologous Fc fraction, and targeting a critical number of epitopes, as well as the unexpected contribution of non-neutralizing clones to the synergistic neutralizing effect are presented and discussed.
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Affiliation(s)
- Eran Diamant
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona 7410001, Israel.
| | - Amram Torgeman
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona 7410001, Israel.
| | - Eyal Ozeri
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona 7410001, Israel.
| | - Ran Zichel
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona 7410001, Israel.
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Abstract
Maternal and neonatal tetanus is still a substantial but preventable cause of mortality in many developing countries. Case fatality from these diseases remains high and treatment is limited by scarcity of resources and effective drug treatments. The Maternal and Neonatal Tetanus Elimination Initiative, launched by WHO and its partners, has made substantial progress in eliminating maternal and neonatal tetanus. Sustained emphasis on improvement of vaccination coverage, birth hygiene, and surveillance, with specific approaches in high-risk areas, has meant that the incidence of the disease continues to fall. Despite this progress, an estimated 58,000 neonates and an unknown number of mothers die every year from tetanus. As of June, 2014, 24 countries are still to eliminate the disease. Maintenance of elimination needs ongoing vaccination programmes and improved public health infrastructure.
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Affiliation(s)
- C Louise Thwaites
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.
| | - Nicholas J Beeching
- Liverpool School of Tropical Medicine, and Tropical and Infectious Disease Unit, Royal Liverpool University Hospital, and National Institute for Health Research Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, UK
| | - Charles R Newton
- Kenya Medical Research Institute - Wellcome Trust Collaborative Programme, Kilifi, Kenya; Department of Psychiatry, University of Oxford, Oxford, UK
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29
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Kammerer RA, Benoit RM. Botulinum neurotoxins: new questions arising from structural biology. Trends Biochem Sci 2014; 39:517-26. [PMID: 25282537 DOI: 10.1016/j.tibs.2014.08.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/18/2014] [Accepted: 08/21/2014] [Indexed: 11/29/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the most toxic substances known and cause botulism in vertebrates. They have also emerged as effective and powerful reagents for cosmetic and medical applications. One important prerequisite for understanding BoNT function in disease, and the further development of the toxins for cosmetic and medical applications, is a detailed knowledge of BoNT interactions with non-toxic neurotoxin-associated proteins and cell surface receptors. Based on the substantial recent progress in obtaining high-resolution crystal structures of key BoNT complexes, we summarize the major advances in understanding BoNT interactions and discuss the resulting potential implications, in particular those relating to BoNT serotype A.
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Affiliation(s)
- Richard A Kammerer
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
| | - Roger M Benoit
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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30
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Cerdà-Costa N, Gomis-Rüth FX. Architecture and function of metallopeptidase catalytic domains. Protein Sci 2014; 23:123-44. [PMID: 24596965 DOI: 10.1002/pro.2400] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The cleavage of peptide bonds by metallopeptidases (MPs) is essential for life. These ubiquitous enzymes participate in all major physiological processes, and so their deregulation leads to diseases ranging from cancer and metastasis, inflammation, and microbial infection to neurological insults and cardiovascular disorders. MPs cleave their substrates without a covalent intermediate in a single-step reaction involving a solvent molecule, a general base/acid, and a mono- or dinuclear catalytic metal site. Most monometallic MPs comprise a short metal-binding motif (HEXXH), which includes two metal-binding histidines and a general base/acid glutamate, and they are grouped into the zincin tribe of MPs. The latter divides mainly into the gluzincin and metzincin clans. Metzincins consist of globular ∼ 130-270-residue catalytic domains, which are usually preceded by N-terminal pro-segments, typically required for folding and latency maintenance. The catalytic domains are often followed by C-terminal domains for substrate recognition and other protein-protein interactions, anchoring to membranes, oligomerization, and compartmentalization. Metzincin catalytic domains consist of a structurally conserved N-terminal subdomain spanning a five-stranded β-sheet, a backing helix, and an active-site helix. The latter contains most of the metal-binding motif, which is here characteristically extended to HEXXHXXGXX(H,D). Downstream C-terminal subdomains are generally shorter, differ more among metzincins, and mainly share a conserved loop--the Met-turn--and a C-terminal helix. The accumulated structural data from more than 300 deposited structures of the 12 currently characterized metzincin families reviewed here provide detailed knowledge of the molecular features of their catalytic domains, help in our understanding of their working mechanisms, and form the basis for the design of novel drugs.
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Anniballi F, Lonati D, Fiore A, Auricchio B, De Medici D, Locatelli CA. New targets in the search for preventive and therapeutic agents for botulism. Expert Rev Anti Infect Ther 2014; 12:1075-86. [PMID: 25089560 DOI: 10.1586/14787210.2014.945917] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Botulism is a severe neuroparalytic disease resulting from exposure to one of the most poisonous toxins to humans. Because of this high potency and the use of toxins as biological weapons, botulism is a public health concern and each case represents an emergency. Current therapy involves respiratory supportive care and anti-toxins administration. As a preventive measure, vaccination against toxins represents an effective strategy but is undesirable due the rarity of botulism and the effectiveness of toxins in treating several neuromuscular disorders. This paper summarizes the current issues in botulism treatment and prevention, highlighting the challenge for future researches.
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Affiliation(s)
- Fabrizio Anniballi
- Department of Veterinary Public Health and Food Safety, National Reference Centre for Botulism, Istituto Superiore di Sanità, Viale Regina Elena, 299 - 00161 Rome, Italy
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Structural insight into exosite binding and discovery of novel exosite inhibitors of botulinum neurotoxin serotype A through in silico screening. J Comput Aided Mol Des 2014; 28:765-78. [PMID: 24958623 DOI: 10.1007/s10822-014-9758-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Accepted: 05/26/2014] [Indexed: 01/25/2023]
Abstract
Botulinum neurotoxin serotype A (BoNT/A) is the most lethal toxin among the Tier 1 Select Agents. Development of potent and selective small molecule inhibitors against BoNT/A zinc metalloprotease remains a challenging problem due to its exceptionally large substrate binding surface and conformational plasticity. The exosites of the catalytic domain of BoNT/A are intriguing alternative sites for small molecule intervention, but their suitability for inhibitor design remains largely unexplored. In this study, we employed two recently identified exosite inhibitors, D-chicoric acid and lomofungin, to probe the structural features of the exosites and molecular mechanisms of synergistic inhibition. The results showed that D-chicoric acid favors binding at the α-exosite, whereas lomofungin preferentially binds at the β-exosite by mimicking the substrate β-sheet binding interaction. Molecular dynamics simulations and binding interaction analysis of the exosite inhibitors with BoNT/A revealed key elements and hotspots that likely contribute to the inhibitor binding and synergistic inhibition. Finally, we performed database virtual screening for novel inhibitors of BoNT/A targeting the exosites. Hits C1 and C2 showed non-competitive inhibition and likely target the α- and β-exosites, respectively. The identified exosite inhibitors may provide novel candidates for structure-based development of therapeutics against BoNT/A intoxication.
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33
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Schnaar RL, Gerardy-Schahn R, Hildebrandt H. Sialic acids in the brain: gangliosides and polysialic acid in nervous system development, stability, disease, and regeneration. Physiol Rev 2014; 94:461-518. [PMID: 24692354 DOI: 10.1152/physrev.00033.2013] [Citation(s) in RCA: 497] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Every cell in nature carries a rich surface coat of glycans, its glycocalyx, which constitutes the cell's interface with its environment. In eukaryotes, the glycocalyx is composed of glycolipids, glycoproteins, and proteoglycans, the compositions of which vary among different tissues and cell types. Many of the linear and branched glycans on cell surface glycoproteins and glycolipids of vertebrates are terminated with sialic acids, nine-carbon sugars with a carboxylic acid, a glycerol side-chain, and an N-acyl group that, along with their display at the outmost end of cell surface glycans, provide for varied molecular interactions. Among their functions, sialic acids regulate cell-cell interactions, modulate the activities of their glycoprotein and glycolipid scaffolds as well as other cell surface molecules, and are receptors for pathogens and toxins. In the brain, two families of sialoglycans are of particular interest: gangliosides and polysialic acid. Gangliosides, sialylated glycosphingolipids, are the most abundant sialoglycans of nerve cells. Mouse genetic studies and human disorders of ganglioside metabolism implicate gangliosides in axon-myelin interactions, axon stability, axon regeneration, and the modulation of nerve cell excitability. Polysialic acid is a unique homopolymer that reaches >90 sialic acid residues attached to select glycoproteins, especially the neural cell adhesion molecule in the brain. Molecular, cellular, and genetic studies implicate polysialic acid in the control of cell-cell and cell-matrix interactions, intermolecular interactions at cell surfaces, and interactions with other molecules in the cellular environment. Polysialic acid is essential for appropriate brain development, and polymorphisms in the human genes responsible for polysialic acid biosynthesis are associated with psychiatric disorders including schizophrenia, autism, and bipolar disorder. Polysialic acid also appears to play a role in adult brain plasticity, including regeneration. Together, vertebrate brain sialoglycans are key regulatory components that contribute to proper development, maintenance, and health of the nervous system.
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Pantano S, Montecucco C. The blockade of the neurotransmitter release apparatus by botulinum neurotoxins. Cell Mol Life Sci 2014; 71:793-811. [PMID: 23749048 PMCID: PMC11113401 DOI: 10.1007/s00018-013-1380-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/15/2013] [Accepted: 05/16/2013] [Indexed: 12/22/2022]
Abstract
The high toxicity of the seven serotypes of botulinum neurotoxins (BoNT/A to G), together with their specificity and reversibility, includes them in the list A of potential bioterrorism weapons and, at the same time, among the therapeutics of choice for a variety of human syndromes. They invade nerve terminals and cleave specifically the three proteins which form the heterotrimeric SNAP REceptors (SNARE) complex that mediates neurotransmitter release. The BoNT-induced cleavage of the SNARE proteins explains by itself the paralysing activity of the BoNTs because the truncated proteins cannot form the SNARE complex. However, in the case of BoNT/A, the most widely used toxin in therapy, additional factors come into play as it only removes a few residues from the synaptosomal associate protein of 25 kDa C-terminus and this results in a long duration of action. To explain these facts and other experimental data, we present here a model for the assembly of the neuroexocytosis apparatus in which Synaptotagmin and Complexin first assist the zippering of the SNARE complex, and then stabilize and clamp an octameric radial assembly of the SNARE complexes.
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Affiliation(s)
- Sergio Pantano
- Institut Pasteur de Montevideo, Calle Mataojo 2020, CP 11400 Montevideo, Uruguay
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Padua, Italy
- Institute of Neuroscience, National Research Council, Viale G. Colombo 3, 35121 Padua, Italy
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Kwon SJ, Jeong EJ, Yoo YC, Cai C, Yang GH, Lee JC, Dordick JS, Linhardt RJ, Lee KB. High sensitivity detection of active botulinum neurotoxin by glyco-quantitative polymerase chain-reaction. Anal Chem 2014; 86:2279-84. [PMID: 24506443 PMCID: PMC3985614 DOI: 10.1021/ac500262d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
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The sensitive detection of highly
toxic botulinum neurotoxin (BoNT)
from Clostridium botulinum is of critical importance
because it causes human illnesses if foodborne or introduced in wounds
and as an iatrogenic substance. Moreover, it has been recently considered
a possible biological warfare agent. Over the past decade, significant
progress has been made in BoNT detection technologies, including mouse
lethality assays, enzyme-linked immunosorbent assays, and endopeptidase
assays and by mass spectrometry. Critical assay requirements, including
rapid assay, active toxin detection, sensitive and accurate detection,
still remain challenging. Here, we present a novel method to detect
active BoNTs using a Glyco-quantitative polymerase chain-reaction
(qPCR) approach. Sialyllactose, which interacts with the binding-domain
of BoNTs, is incorporated into a sialyllactose-DNA conjugate as a
binding-probe for active BoNT and recovered through BoNT-immunoprecipitation.
Glyco-qPCR analysis of the bound sialyllactose-DNA is then used to
detect low attomolar concentrations of BoNT and attomolar to femtomolar
concentrations of BoNT in honey, the most common foodborne source
of infant botulism.
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Affiliation(s)
- Seok Joon Kwon
- Department of Chemical and Biological Engineering, Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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Affiliation(s)
- Vincent B Young
- Departments of Internal Medicine/Infectious Diseases Division
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37
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Structure of dual receptor binding to botulinum neurotoxin B. Nat Commun 2013; 4:2058. [PMID: 23807078 PMCID: PMC3752466 DOI: 10.1038/ncomms3058] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/23/2013] [Indexed: 11/08/2022] Open
Abstract
Botulinum neurotoxins are highly toxic, and bind two receptors to achieve their high affinity and specificity for neurons. Here we present the first structure of a botulinum neurotoxin bound to both its receptors. We determine the 2.3-Å structure of a ternary complex of botulinum neurotoxin type B bound to both its protein receptor synaptotagmin II and its ganglioside receptor GD1a. We show that there is no direct contact between the two receptors, and that the binding affinity towards synaptotagmin II is not influenced by the presence of GD1a. The interactions of botulinum neurotoxin type B with the sialic acid 5 moiety of GD1a are important for the ganglioside selectivity. The structure demonstrates that the protein receptor and the ganglioside receptor occupy nearby but separate binding sites, thus providing two independent anchoring points.
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Yousefi M, Khosravi-Eghbal R, Reza Mahmoudi A, Jeddi-Tehrani M, Rabbani H, Shokri F. Comparative in vitro and in vivo assessment of toxin neutralization by anti-tetanus toxin monoclonal antibodies. Hum Vaccin Immunother 2013; 10:344-51. [PMID: 24126015 DOI: 10.4161/hv.26769] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Tetanus is caused by the tetanus neurotoxin (TeNT), a 150 kDa single polypeptide molecule which is cleaved into an active two-chain molecule composed of a 50 kDa N-terminal light (L) and a 100 kDa C-terminal heavy (H) chains. Recently, extensive effort has focused on characterization of TeNT binding receptors and toxin neutralization by monoclonal antibodies (mAbs). Toxin binding inhibition and neutralization is routinely assessed either in vitro by the ganglioside GT1b binding inhibition assay or in vivo using an animal model. These two assay systems have never been compared. In the present study, we report characterization of eleven mAbs against different parts of TeNT. The toxin inhibitory and neutralization activity of the mAbs was assessed in vitro and in vivo respectively. Our data demonstrated that seven mAbs bind to fragment C of the heavy chain, two mAbs react with the light chain, one mAb recognizes both chains and one mAb reacts with neither light chain nor fragment C. Six fragment C specific mAbs were able to inhibit TeNT binding to GT1b ganglioside in vitro but three failed to neutralize the toxin in vivo. One in vitro inhibitory mAb (1F3E3) was found to synergize with the in vivo neutralizing mAbs to reduce toxin lethal activity in vivo. Sequencing of the immunoglobulin heavy and light chain variable region genes revealed that the three in vivo neutralizing mAbs were derived from a common origin. Altogether, our data suggests that fragment C specific mAbs contribute to toxin neutralization in both systems, though some of the GT1b binding inhibitory mAbs may not be able to neutralize TeNT in vivo.
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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
| | - Roya Khosravi-Eghbal
- Monoclonal Antibody Research Center; Avicenna Research Institute; ACECR; Tehran, Iran
| | - Ahmad Reza Mahmoudi
- Monoclonal Antibody Research Center; Avicenna Research Institute; ACECR; Tehran, Iran
| | - Mahmood Jeddi-Tehrani
- Monoclonal Antibody Research Center; Avicenna Research Institute; ACECR; Tehran, Iran
| | - Hodjatallah Rabbani
- 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
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Masuyer G, Chaddock JA, Foster KA, Acharya KR. Engineered botulinum neurotoxins as new therapeutics. Annu Rev Pharmacol Toxicol 2013; 54:27-51. [PMID: 24016211 DOI: 10.1146/annurev-pharmtox-011613-135935] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Botulinum neurotoxins (BoNTs) cause flaccid paralysis by inhibiting neurotransmission at cholinergic nerve terminals. Each BoNT consists of three domains that are essential for toxicity: the binding domain, the translocation domain, and the catalytic light-chain domain. BoNT modular architecture is associated with a multistep mechanism that culminates in the intracellular proteolysis of SNARE (soluble N-ethylmaleimide-sensitive-fusion-protein attachment protein receptor) proteins, which prevents synaptic vesicle exocytosis. As the most toxic proteins known, BoNTs have been extensively studied and are used as pharmaceutical agents to treat an increasing variety of disorders. This review summarizes the level of sophistication reached in BoNT engineering and highlights the diversity of approaches taken to utilize the modularity of the toxin. Improved efficiency and applicability have been achieved by direct mutagenesis and interserotype domain rearrangement. The scope of BoNT activity has been extended to nonneuronal cells and offers the basis for novel biomolecules in the treatment of secretion disorders.
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Affiliation(s)
- Geoffrey Masuyer
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom;
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40
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Berntsson RPA, Peng L, Svensson LM, Dong M, Stenmark P. Crystal structures of botulinum neurotoxin DC in complex with its protein receptors synaptotagmin I and II. Structure 2013; 21:1602-11. [PMID: 23932591 DOI: 10.1016/j.str.2013.06.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 06/28/2013] [Accepted: 06/30/2013] [Indexed: 02/05/2023]
Abstract
Botulinum neurotoxins (BoNTs) can cause paralysis at exceptionally low concentrations and include seven serotypes (BoNT/A-G). The chimeric BoNT/DC toxin has a receptor binding domain similar to the same region in BoNT/C. However, BoNT/DC does not share protein receptor with BoNT/C. Instead, it shares synaptotagmin (Syt) I and II as receptors with BoNT/B, despite their low sequence similarity. Here, we present the crystal structures of the binding domain of BoNT/DC in complex with the recognition domains of its protein receptors, Syt-I and Syt-II. The structures reveal that BoNT/DC possesses a Syt binding site, distinct from the established Syt-II binding site in BoNT/B. Structure-based mutagenesis further shows that hydrophobic interactions play a key role in Syt binding. The structures suggest that the BoNT/DC ganglioside binding sites are independent of the protein receptor binding site. Our results reveal the remarkable versatility in the receptor recognition of the BoNTs.
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41
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Simpson L. The life history of a botulinum toxin molecule. Toxicon 2013; 68:40-59. [DOI: 10.1016/j.toxicon.2013.02.014] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 02/13/2013] [Accepted: 02/19/2013] [Indexed: 12/31/2022]
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42
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Willjes G, Mahrhold S, Strotmeier J, Eichner T, Rummel A, Binz T. Botulinum neurotoxin G binds synaptotagmin-II in a mode similar to that of serotype B: tyrosine 1186 and lysine 1191 cause its lower affinity. Biochemistry 2013; 52:3930-8. [PMID: 23647335 DOI: 10.1021/bi4003502] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Botulinum neurotoxins (BoNTs) block neurotransmitter release by proteolyzing SNARE proteins in peripheral nerve terminals. Entry into neurons occurs subsequent to interaction with gangliosides and a synaptic vesicle protein. Isoforms I and II of synaptotagmin were shown to act as protein receptors for two of the seven BoNT serotypes, BoNT/B and BoNT/G, and for mosaic-type BoNT/DC. BoNT/B and BoNT/G exhibit a homologous binding site for synaptotagmin whose interacting part adopts helical structure upon binding to BoNT/B. Whereas the BoNT/B-synaptotagmin-II interaction has been elucidated in molecular detail, corresponding information about BoNT/G is lacking. Here we systematically mutated the synaptotagmin binding site in BoNT/G and performed a comparative binding analysis with mutants of the cell binding subunit of BoNT/B. The results suggest that synaptotagmin takes the same overall orientation in BoNT/B and BoNT/G governed by the strictly conserved central parts of the toxins' binding site. The surrounding nonconserved areas differently contribute to receptor binding. Reciprocal mutations Y1186W and L1191Y increased the level of binding of BoNT/G approximately to the level of BoNT/B affinity, suggesting a similar synaptotagmin-bound state. The effects of the mutations were confirmed by studying the activity of correspondingly mutated full-length BoNTs. On the basis of these data, molecular modeling experiments were employed to reveal an atomistic model of BoNT/G-synaptotagmin recognition. These data suggest a reduced length and/or a bend in the C-terminal part of the synaptotagmin helix that forms upon contact with BoNT/G as compared with BoNT/B and are in agreement with the data of the mutational analyses.
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43
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Pellett S. Progress in cell based assays for botulinum neurotoxin detection. Curr Top Microbiol Immunol 2013; 364:257-85. [PMID: 23239357 DOI: 10.1007/978-3-642-33570-9_12] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Botulinum neurotoxins (BoNTs) are the most potent human toxins known and the causative agent of botulism, and are widely used as valuable pharmaceuticals. The BoNTs are modular proteins consisting of a heavy chain and a light chain linked by a disulfide bond. Intoxication of neuronal cells by BoNTs is a multi-step process including specific cell binding, endocytosis, conformational change in the endosome, translocation of the enzymatic light chain into the cells cytosol, and SNARE target cleavage. The quantitative and reliable potency determination of fully functional BoNTs produced as active pharmaceutical ingredient (API) requires an assay that considers all steps in the intoxication pathway. The in vivo mouse bioassay has for years been the 'gold standard' assay used for this purpose, but it requires the use of large numbers of mice and thus causes associated costs and ethical concerns. Cell-based assays are currently the only in vitro alternative that detect fully functional BoNTs in a single assay and have been utilized for years for research purposes. Within the last 5 years, several cell-based BoNT detection assays have been developed that are able to quantitatively determine BoNT potency with similar or greater sensitivity than the mouse bioassay. These assays now offer an alternative method for BoNT potency determination. Such quantitative and reliable BoNT potency determination is a crucial step in basic research, in the development of pharmaceutical BoNTs, and in the quantitative detection of neutralizing antibodies.
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Affiliation(s)
- Sabine Pellett
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA.
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44
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Rossetto O, Megighian A, Scorzeto M, Montecucco C. Botulinum neurotoxins. Toxicon 2013; 67:31-6. [PMID: 23435262 DOI: 10.1016/j.toxicon.2013.01.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 01/29/2013] [Indexed: 11/20/2022]
Affiliation(s)
- O Rossetto
- Department of Biomedical Sciences and National Research Council Institute of Neuroscience, University of Padova, Italy, Via G. Colombo 3, 35121 Padova, Italy
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45
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Stevens GB, Silver DA, Zgaga-Griesz A, Bessler WG, Vashist SK, Patel P, Achazi K, Strotmeier J, Worbs S, Dorner MB, Dorner BG, Pauly D, Rummel A, Urban GA, Krueger M. Bioluminescence assay for the highly sensitive detection of botulinum neurotoxin A activity. Analyst 2013; 138:6154-62. [DOI: 10.1039/c3an00525a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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46
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Rapid and selective detection of botulinum neurotoxin serotype-A and -B with a single immunochromatographic test strip. J Immunol Methods 2012; 380:23-9. [DOI: 10.1016/j.jim.2012.03.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 03/28/2012] [Accepted: 03/28/2012] [Indexed: 12/20/2022]
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47
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Caglič D, Dickerson TJ. A coincidence detector triggers botulinum neurotoxin translocation. Future Microbiol 2012; 7:185-8. [PMID: 22324987 DOI: 10.2217/fmb.11.157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the deadliest poisons known to man. They possess a particular duality, rapidly increasing clinical utility for a wide range of disorders and large concern as a possible weapon of bioterrorism. While great strides have been made in the structural and biochemical understanding of the mechanism of intoxication, the specific molecular details behind BoNT translocation out of endosomes remain elusive. In this study, it was conclusively demonstrated that light chain metalloprotease translocation can only occur in the presence of low pH, as is found in endosomes, and GT1b ganglioside coreceptor, whose role was previously thought to only be in cell surface recognition by the toxin. As stated by the authors, the BoNT receptor-binding domain therefore serves as a 'coincidence receptor' in that pH sensing and conformational change to a translocation competent form must be coupled in some way to receptor binding. Further study using atomic force microscopy also suggested the presence of oligomeric toxin channels that can be inhibited by the natural product toosendanin. This data revises the model of BoNT intoxication and demonstrates a mechanism for the amazing temporal and spatial control possessed by this toxin, which ultimately manifests in its extreme potency.
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Affiliation(s)
- Dejan Caglič
- Department of Chemistry & Worm Institute of Research & Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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48
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49
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Masuyer G, Stancombe P, Chaddock JA, Acharya KR. Structures of engineered Clostridium botulinum neurotoxin derivatives. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1466-72. [PMID: 22139146 PMCID: PMC3232119 DOI: 10.1107/s1744309111034671] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 08/23/2011] [Indexed: 11/10/2022]
Abstract
Targeted secretion inhibitors (TSIs) are a new class of engineered biopharmaceutical molecules derived from the botulinum neurotoxins (BoNTs). They consist of the metalloprotease light chain (LC) and translocation domain (Hn) of BoNT; they thus lack the native toxicity towards motor neurons but are able to target soluble N-ethylmaleimide-sensitive fusion protein attachment receptor (SNARE) proteins. These functional fragment (LHn) derivatives are expressed as single-chain proteins and require post-translational activation into di-chain molecules for function. A range of BoNT derivatives have been produced to demonstrate the successful use of engineered SNARE substrate peptides at the LC-Hn interface that gives these molecules self-activating capabilities. Alternatively, recognition sites for specific exoproteases can be engineered to allow controlled activation. Here, the crystal structures of three LHn derivatives are reported between 2.7 and 3.0 Å resolution. Two of these molecules are derivatives of serotype A that contain a SNARE peptide. Additionally, a third structure corresponds to LHn serotype B that includes peptide linkers at the exoprotease activation site. In all three cases the added engineered segments could not be modelled owing to disorder. However, these structures highlight the strong interactions holding the LHn fold together despite the inclusion of significant polypeptide sequences at the LC-Hn interface.
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Affiliation(s)
- Geoffrey Masuyer
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, England
| | - Patrick Stancombe
- Syntaxin Limited, Units 4–10, The Quadrant, Barton Lane, Abingdon, Oxon OX14 3YS, England
| | - John A. Chaddock
- Syntaxin Limited, Units 4–10, The Quadrant, Barton Lane, Abingdon, Oxon OX14 3YS, England
| | - K. Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, England
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