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Park W, Park M, Chun J, Hwang J, Kim S, Choi N, Kim S, Kim S, Jung S, Ko KS, Kweon DH. Delivery of endolysin across outer membrane of Gram-negative bacteria using translocation domain of botulinum neurotoxin. Int J Antimicrob Agents 2024:107216. [PMID: 38795926 DOI: 10.1016/j.ijantimicag.2024.107216] [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: 10/20/2023] [Revised: 04/08/2024] [Accepted: 05/20/2024] [Indexed: 05/28/2024]
Abstract
The emergence of multidrug resistant pathogens has outpaced the development of new antibiotics, leading to renewed interest in endolysins. Endolysins have been investigated as novel biocontrol agents for Gram-positive bacteria. However, their efficacy against Gram-negative species is limited by the barrier presented by their outer membrane, which prevents endolysin access to the peptidoglycan substrate. Here, we used the translocation domain of botulinum neurotoxin (BoNT) to deliver endolysin across the outer membrane of Gram-negative bacteria. The translocation domain selectively interacts with and penetrates membranes composed of anionic lipids, which have been used in nature to deliver various proteins into animal cells. In addition to the BoNT translocation domain, we have fused bacteriophage-derived receptor binding protein to endolysins. This allows the attached protein to efficiently bind to a broad spectrum of Gram-negative bacteria. By attaching these target-binding and translocation machinery to endolysins, we aimed to develop an engineered endolysin with broad-spectrum targeting and enhanced antibacterial activity against Gram-negative species. To validate our strategy, we designed engineered endolysins using two well-known endolysins, T5 and LysPA26, and tested them against 23 strains from six species of Gram-negative bacteria, confirming that our machinery can act broadly. In particular, we observed a 2.32 log reduction in 30 minutes with only 0.5 µM against an A. baumannii isolate. We also used the SpyTag/SpyCatcher system to easily attach target-binding proteins, thereby improving its target binding ability. Overall, our newly developed endolysin engineering strategy may be a promising approach to control multidrug-resistant Gram-negative bacterial strains.
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Affiliation(s)
- Wonbeom Park
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Myungseo Park
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea; Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34114, Republic of Korea
| | - Jihwan Chun
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jaehyeon Hwang
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Suhyun Kim
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Nayoon Choi
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Sumin Kim
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seongju Kim
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Sangwon Jung
- Research Center, MVRIX, Anyang 14058, Republic of Korea
| | - Kwan Soo Ko
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Dae-Hyuk Kweon
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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2
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Leka O, Wu Y, Zanetti G, Furler S, Reinberg T, Marinho J, Schaefer JV, Plückthun A, Li X, Pirazzini M, Kammerer RA. A DARPin promotes faster onset of botulinum neurotoxin A1 action. Nat Commun 2023; 14:8317. [PMID: 38110403 PMCID: PMC10728214 DOI: 10.1038/s41467-023-44102-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 11/30/2023] [Indexed: 12/20/2023] Open
Abstract
In this study, we characterize Designed Ankyrin Repeat Proteins (DARPins) as investigative tools to probe botulinum neurotoxin A1 (BoNT/A1) structure and function. We identify DARPin-F5 that completely blocks SNAP25 substrate cleavage by BoNT/A1 in vitro. X-ray crystallography reveals that DARPin-F5 inhibits BoNT/A1 activity by interacting with a substrate-binding region between the α- and β-exosite. This DARPin does not block substrate cleavage of BoNT/A3, indicating that DARPin-F5 is a subtype-specific inhibitor. BoNT/A1 Glu-171 plays a critical role in the interaction with DARPin-F5 and its mutation to Asp, the residue found in BoNT/A3, results in a loss of inhibition of substrate cleavage. In contrast to the in vitro results, DARPin-F5 promotes faster substrate cleavage of BoNT/A1 in primary neurons and muscle tissue by increasing toxin translocation. Our findings could have important implications for the application of BoNT/A1 in therapeutic areas requiring faster onset of toxin action combined with long persistence.
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Affiliation(s)
- Oneda Leka
- Laboratory of Biomolecular Research, Division of Biology, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
| | - Yufan Wu
- Laboratory of Biomolecular Research, Division of Biology, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
| | - Giulia Zanetti
- Department of Biomedical Sciences, University of Padova, 35121, Padova, Italy
| | - Sven Furler
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Thomas Reinberg
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Joana Marinho
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Jonas V Schaefer
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Xiaodan Li
- Laboratory of Biomolecular Research, Division of Biology, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, 35121, Padova, Italy
| | - Richard A Kammerer
- Laboratory of Biomolecular Research, Division of Biology, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland.
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3
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Tian S, Liu Y, Appleton E, Wang H, Church GM, Dong M. Targeted intracellular delivery of Cas13 and Cas9 nucleases using bacterial toxin-based platforms. Cell Rep 2022; 38:110476. [PMID: 35263584 PMCID: PMC8958846 DOI: 10.1016/j.celrep.2022.110476] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 12/26/2021] [Accepted: 02/11/2022] [Indexed: 02/06/2023] Open
Abstract
Targeted delivery of therapeutic proteins toward specific cells and across cell membranes remains major challenges. Here, we develop protein-based delivery systems utilizing detoxified single-chain bacterial toxins such as diphtheria toxin (DT) and botulinum neurotoxin (BoNT)-like toxin, BoNT/X, as carriers. The system can deliver large protein cargoes including Cas13a, CasRx, Cas9, and Cre recombinase into cells in a receptor-dependent manner, although delivery of ribonucleoproteins containing guide RNAs is not successful. Delivery of Cas13a and CasRx, together with guide RNA expression, reduces mRNAs encoding GFP, SARS-CoV-2 fragments, and endogenous proteins PPIB, KRAS, and CXCR4 in multiple cell lines. Delivery of Cre recombinase modifies the reporter loci in cells. Delivery of Cas9, together with guide RNA expression, generates mutations at the targeted genomic sites in cell lines and induced pluripotent stem cell (iPSC)-derived human neurons. These findings establish modular delivery systems based on single-chain bacterial toxins for delivery of membrane-impermeable therapeutics into targeted cells.
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Affiliation(s)
- Songhai Tian
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA.
| | - Yang Liu
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA; Department of Nephrology, The First Hospital of Jilin University, Changchun, 130021, China
| | - Evan Appleton
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA 02115, USA
| | - Huan Wang
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - George M Church
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA 02115, USA
| | - Min Dong
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA.
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4
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Miyashita SI, Zhang J, Zhang S, Shoemaker CB, Dong M. Delivery of single-domain antibodies into neurons using a chimeric toxin-based platform is therapeutic in mouse models of botulism. Sci Transl Med 2021; 13:13/575/eaaz4197. [PMID: 33408184 DOI: 10.1126/scitranslmed.aaz4197] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 05/01/2020] [Indexed: 12/15/2022]
Abstract
Efficient penetration of cell membranes and specific targeting of a cell type represent major challenges for developing therapeutics toward intracellular targets. One example facing these hurdles is to develop post-exposure treatment for botulinum neurotoxins (BoNTs), a group of bacterial toxins (BoNT/A to BoNT/G) that are major potential bioterrorism agents. BoNTs enter motor neurons, block neurotransmitter release, and cause a paralytic disease botulism. Members of BoNTs such as BoNT/A exhibit extremely long half-life within neurons, resulting in persistent paralysis for months, yet there are no therapeutics that can inhibit BoNTs once they enter neurons. Here, we developed a chimeric toxin-based delivery platform by fusing the receptor-binding domain of a BoNT, which targets neurons, with the membrane translocation domain and inactivated protease domain of the recently discovered BoNT-like toxin BoNT/X, which can deliver cargoes across endosomal membranes into the cytosol. A therapeutic protein was then created by fusing a single-domain antibody (nanobody) against BoNT/A with the delivery platform. In vitro characterization demonstrated that nanobodies were delivered into cultured neurons and neutralized BoNT/A in neurons. Administration of this protein in mice shortened duration of local muscle paralysis, restoring muscle function within hours, and rescued mice from systemic toxicity of lethal doses of BoNT/A. Fusion of two nanobodies, one against BoNT/A and the other against BoNT/B, created a multivalent therapeutic protein able to neutralize both BoNT/A and BoNT/B in mice. These studies provide an effective post-exposure treatment for botulism and establish a platform for intracellular delivery of therapeutics targeting cytosolic proteins and processes.
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Affiliation(s)
- Shin-Ichiro Miyashita
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jie Zhang
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Sicai Zhang
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Charles B Shoemaker
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA 01536, USA
| | - Min Dong
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA. .,Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
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5
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Tremblay JM, Vazquez-Cintron E, Lam KH, Mukherjee J, Bedenice D, Ondeck CA, Conroy MT, Bodt SML, Winner BM, Webb RP, Ichtchenko K, Jin R, McNutt PM, Shoemaker CB. Camelid VHH Antibodies that Neutralize Botulinum Neurotoxin Serotype E Intoxication or Protease Function. Toxins (Basel) 2020; 12:toxins12100611. [PMID: 32987745 PMCID: PMC7598594 DOI: 10.3390/toxins12100611] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/02/2020] [Accepted: 09/11/2020] [Indexed: 12/12/2022] Open
Abstract
Botulinum neurotoxin (BoNT) serotype E is one of three serotypes that cause the preponderance of human botulism cases and is a Tier 1 Select Agent. BoNT/E is unusual among BoNT serotypes for its rapid onset and short duration of intoxication. Here we report two large panels of unique, unrelated camelid single-domain antibodies (VHHs) that were selected for their ability to bind to BoNT/E holotoxin and/or to the BoNT/E light chain protease domain (LC/E). The 19 VHHs which bind to BoNT/E were characterized for their subunit specificity and 8 VHHs displayed the ability to neutralize BoNT/E intoxication of neurons. Heterodimer antitoxins consisting of two BoNT/E-neutralizing VHHs, including one heterodimer designed using structural information for simultaneous binding, were shown to protect mice against co-administered toxin challenges of up to 500 MIPLD50. The 22 unique VHHs which bind to LC/E were characterized for their binding properties and 9 displayed the ability to inhibit LC/E protease activity. Surprisingly, VHHs selected on plastic-coated LC/E were virtually unable to recognize soluble or captured LC/E while VHHs selected on captured LC/E were poorly able to recognize LC/E coated to a plastic surface. This panel of anti-LC/E VHHs offer insight into BoNT/E function, and some may have value as components of therapeutic antidotes that reverse paralysis following BoNT/E exposures.
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Affiliation(s)
- Jacqueline M. Tremblay
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536, USA; (J.M.T.); (J.M.)
| | - Edwin Vazquez-Cintron
- The United States Army Medical Research Institute of Chemical Defense, Fort Detrick, MD 21010, USA; (E.V.-C.); (C.A.O.); (M.T.C.); (S.M.L.B.); (B.M.W.); (P.M.M.)
| | - Kwok-Ho Lam
- Department of Physiology & Biophysics, University of California, Irvine, CA 92697-4560, USA; (K.-H.L.); (R.J.)
| | - Jean Mukherjee
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536, USA; (J.M.T.); (J.M.)
| | - Daniela Bedenice
- Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536, USA;
| | - Celinia A. Ondeck
- The United States Army Medical Research Institute of Chemical Defense, Fort Detrick, MD 21010, USA; (E.V.-C.); (C.A.O.); (M.T.C.); (S.M.L.B.); (B.M.W.); (P.M.M.)
| | - Matthieu T. Conroy
- The United States Army Medical Research Institute of Chemical Defense, Fort Detrick, MD 21010, USA; (E.V.-C.); (C.A.O.); (M.T.C.); (S.M.L.B.); (B.M.W.); (P.M.M.)
| | - Skylar M. L. Bodt
- The United States Army Medical Research Institute of Chemical Defense, Fort Detrick, MD 21010, USA; (E.V.-C.); (C.A.O.); (M.T.C.); (S.M.L.B.); (B.M.W.); (P.M.M.)
| | - Brittany M. Winner
- The United States Army Medical Research Institute of Chemical Defense, Fort Detrick, MD 21010, USA; (E.V.-C.); (C.A.O.); (M.T.C.); (S.M.L.B.); (B.M.W.); (P.M.M.)
| | - Robert P. Webb
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, Ft. Detrick, MD 21702-5011, USA;
| | - Konstantin Ichtchenko
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA;
| | - Rongsheng Jin
- Department of Physiology & Biophysics, University of California, Irvine, CA 92697-4560, USA; (K.-H.L.); (R.J.)
| | - Patrick M. McNutt
- The United States Army Medical Research Institute of Chemical Defense, Fort Detrick, MD 21010, USA; (E.V.-C.); (C.A.O.); (M.T.C.); (S.M.L.B.); (B.M.W.); (P.M.M.)
| | - Charles B. Shoemaker
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536, USA; (J.M.T.); (J.M.)
- Correspondence:
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6
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Leese C, Bresnahan R, Doran C, Simsek D, Fellows AD, Restani L, Caleo M, Schiavo G, Mavlyutov T, Henke T, Binz T, Davletov B. Duplication of clostridial binding domains for enhanced macromolecular delivery into neurons. Toxicon X 2020; 5:100019. [PMID: 32140681 PMCID: PMC7043326 DOI: 10.1016/j.toxcx.2019.100019] [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: 08/16/2019] [Revised: 11/25/2019] [Accepted: 12/19/2019] [Indexed: 12/03/2022] Open
Abstract
Neurological diseases constitute a quarter of global disease burden and are expected to rise worldwide with the ageing of human populations. There is an increasing need to develop new molecular systems which can deliver drugs specifically into neurons, non-dividing cells meant to last a human lifetime. Neuronal drug delivery must rely on agents which can recognise neurons with high specificity and affinity. Here we used a recently introduced ‘stapling’ system to prepare macromolecules carrying duplicated binding domains from the clostridial family of neurotoxins. We engineered individual parts of clostridial neurotoxins separately and combined them using a strong alpha-helical bundle. We show that combining two identical binding domains of tetanus and botulinum type D neurotoxins, in a sterically defined way by protein stapling, allows enhanced intracellular delivery of molecules into neurons. We also engineered a botulinum neurotoxin type C variant with a duplicated binding domain which increased enzymatic delivery compared to the native type C toxin. We conclude that duplication of the binding parts of tetanus or botulinum neurotoxins will allow production of high avidity agents which could deliver imaging reagents and large therapeutic enzymes into neurons with superior efficiency. Macromolecules carrying duplicated clostridial binding domains (Hc) were produced. Double tetanus Hc increased protein delivery into cultured rodent neurones. Double tetanus Hc increased enzyme delivery into rodent spinal cord and brain area. Double BoNT/D Hc increased enzyme delivery into rat and human neurones in culture. Recombinant double-Hc BoNT/C was engineered, increasing delivery in cell cultures.
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Affiliation(s)
- Charlotte Leese
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Rebecca Bresnahan
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Ciara Doran
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Deniz Simsek
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Alexander D Fellows
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Laura Restani
- CNR Neuroscience Institute, Pisa, 1-56124 Pisa, Italy
| | - Matteo Caleo
- CNR Neuroscience Institute, Pisa, 1-56124 Pisa, Italy
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, WC1N 3BG, UK.,UK Dementia Research Institute, University College London, London, WC1E 6BT, UK
| | - Timur Mavlyutov
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Tina Henke
- Institute of Cellular Biochemistry, Hannover Medical School, Hannover, 30625, Germany
| | - Thomas Binz
- Institute of Cellular Biochemistry, Hannover Medical School, Hannover, 30625, Germany
| | - Bazbek Davletov
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
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7
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Steward L, Brin MF, Brideau-Andersen A. Novel Native and Engineered Botulinum Neurotoxins. Handb Exp Pharmacol 2020; 263:63-89. [PMID: 32274579 DOI: 10.1007/164_2020_351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Botulinum neurotoxins (BoNTs), produced by Clostridia and other bacteria, are the most potent toxins known. Their cleavage of the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) proteins in neurons prevents the release of neurotransmitters, thus resulting in the muscle paralysis that is characteristic of botulism. This mechanism of action has been exploited for a variety of therapeutic and cosmetic applications of BoNTs. This chapter provides an overview of the native BoNTs, including the classical serotypes and their clinical use, mosaic BoNTs, and novel BoNTs that have been recently identified in clostridial and non-clostridial strains. In addition, the modular structure of native BoNTs, which are composed of a light chain and a heavy chain, is amenable to a multitude of novel fusions and mutations using molecular biology techniques. These novel recombinant BoNTs have been used or are being developed to further characterize the biology of toxins, to assist in vaccine production, to serve as delivery vehicles to neurons, and to be utilized as novel therapeutics for both neuronal and non-neuronal cells.
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Affiliation(s)
| | - Mitchell F Brin
- Allergan plc, Irvine, CA, USA.,University of California, Irvine, CA, USA
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8
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Rossetto O, Pirazzini M, Lista F, Montecucco C. The role of the single interchains disulfide bond in tetanus and botulinum neurotoxins and the development of antitetanus and antibotulism drugs. Cell Microbiol 2019; 21:e13037. [PMID: 31050145 PMCID: PMC6899712 DOI: 10.1111/cmi.13037] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/18/2019] [Accepted: 04/30/2019] [Indexed: 01/02/2023]
Abstract
A large number of bacterial toxins consist of active and cell binding protomers linked by an interchain disulfide bridge. The largest family of such disulfide‐bridged exotoxins is that of the clostridial neurotoxins that consist of two chains and comprise the tetanus neurotoxins causing tetanus and the botulinum neurotoxins causing botulism. Reduction of the interchain disulfide abolishes toxicity, and we discuss the experiments that revealed the role of this structural element in neuronal intoxication. The redox couple thioredoxin reductase–thioredoxin (TrxR‐Trx) was identified as the responsible for reduction of this disulfide occurring on the cytosolic surface of synaptic vesicles. We then discuss the very relevant finding that drugs that inhibit TrxR‐Trx also prevent botulism. On this basis, we propose that ebselen and PX‐12, two TrxR‐Trx specific drugs previously used in clinical trials in humans, satisfy all the requirements for clinical tests aiming at evaluating their capacity to effectively counteract human and animal botulism arising from intestinal toxaemias such as infant botulism.
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Affiliation(s)
- Ornella Rossetto
- Dipartimento di Scienze Biomediche, Università di Padova, Padua, Italy
| | - Marco Pirazzini
- Dipartimento di Scienze Biomediche, Università di Padova, Padua, Italy
| | - Florigio Lista
- Sezione di Istologia e Biologia Molecolare, Centro di ricerca Medica e Veterinaria del Ministero della Difesa, Rome, Italy
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche, Università di Padova, Padua, Italy.,Istituto Neuroscienze del CNR, Università di Padova, Padua, Italy
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9
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Kutschenko A, Weisemann J, Kollewe K, Fiedler T, Alvermann S, Böselt S, Escher C, Garde N, Gingele S, Kaehler SB, Karatschai R, Krüger THC, Sikorra S, Tacik P, Wegner F, Wollmann J, Bigalke H, Wohlfarth K, Rummel A. Botulinum neurotoxin serotype D - A potential treatment alternative for BoNT/A and B non-responding patients. Clin Neurophysiol 2019; 130:1066-1073. [PMID: 30871800 DOI: 10.1016/j.clinph.2019.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/28/2019] [Accepted: 02/10/2019] [Indexed: 11/17/2022]
Abstract
OBJECTIVES Botulinum neurotoxin serotypes A and B (BoNT/A & B) are highly effective medicines to treat hyperactive cholinergic neurons. Due to neutralizing antibody formation, some patients may become non-responders. In these cases, the serotypes BoNT/C-G might become treatment alternatives. BoNT/D is genetically least related to BoNT/A & B and thereby circumventing neutralisation in A/B non-responders. We produced BoNT/D and compared its pharmacology with BoNT/A ex vivo in mice tissue and in vivo in human volunteers. METHODS BoNT/D was expressed recombinantly in E. coli, isolated by chromatography and its ex vivo potency was determined at mouse phrenic nerve hemidiaphragm preparations. Different doses of BoNT/D or incobotulinumtoxinA were injected into the extensor digitorum brevis (EDB) muscles (n = 30) of human volunteers. Their compound muscle action potentials were measured 11 times by electroneurography within 220 days. RESULTS Despite a 3.7-fold lower ex vivo potency in mice, a 110-fold higher dosage of BoNT/D achieved the same clinical effect as incobotulinumtoxinA while showing a 50% shortened duration of action. CONCLUSIONS BoNT/D blocks dose-dependently acetylcholine release in human motoneurons upon intramuscular administration, but its potency and duration of action is inferior to approved BoNT/A based drugs. SIGNIFICANCE BoNT/D constitutes a potential treatment alternative for BoNT/A & B non-responders.
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Affiliation(s)
- Anna Kutschenko
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Jasmin Weisemann
- Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Katja Kollewe
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Thiemo Fiedler
- Kliniken für Neurologie, Frührehabilitation und Stroke Unit, Berufsgenossenschaftliche Kliniken Bergmannstrost, Halle (Saale), Germany
| | - Sascha Alvermann
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Sebastian Böselt
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Claus Escher
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Niklas Garde
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Stefan Gingele
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Stefan-Benno Kaehler
- Kliniken für Neurologie, Frührehabilitation und Stroke Unit, Berufsgenossenschaftliche Kliniken Bergmannstrost, Halle (Saale), Germany
| | - Ralf Karatschai
- Kliniken für Neurologie, Frührehabilitation und Stroke Unit, Berufsgenossenschaftliche Kliniken Bergmannstrost, Halle (Saale), Germany
| | - Tillmann H C Krüger
- Klinik für Psychiatrie, Sozialpsychiatrie und Psychotherapie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Stefan Sikorra
- Institut für Zellbiochemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Pawel Tacik
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Florian Wegner
- Neurologische Klinik mit Klinischer Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Johannes Wollmann
- Kliniken für Neurologie, Frührehabilitation und Stroke Unit, Berufsgenossenschaftliche Kliniken Bergmannstrost, Halle (Saale), Germany
| | - Hans Bigalke
- Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Kai Wohlfarth
- Kliniken für Neurologie, Frührehabilitation und Stroke Unit, Berufsgenossenschaftliche Kliniken Bergmannstrost, Halle (Saale), Germany.
| | - Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany.
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10
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Hao F, Feng Y, Guan Y. A Novel Botulinum Toxin TAT-EGFP-HCS Fusion Protein Capable of Specific Delivery Through the Blood-brain Barrier to the Central Nervous System. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2019; 18:37-43. [PMID: 30318007 DOI: 10.2174/1871527317666181011113215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/12/2018] [Accepted: 10/04/2018] [Indexed: 11/22/2022]
Abstract
Objective: Botulinum toxin has many applications in the treatment of central diseases, as
biological macromolecules, it is difficult to pass through the blood-brain barrier which greatly limits
their application. In this paper, we verified whether the botulinum toxin heavy chain HCS has a specific
neural guidance function.
Methods:
We have constructed a fusion protein with botulinum toxin heavy chain and a membrane penetrating
peptide TAT (TAT-EGFP-HCS). Recombinant plasmid of botulinum toxin light chain (LC) and
TAT were also constructed. The biological activity of HCS, LC, TAT-EGFP-HCS and TAT-EGFP-LC
were measured by its ability to cleave protein SNAP-25. The intracellular expression efficiency was
evaluated by detecting the fluorescence intensity of EGFP in the cells by fluorescence microscopy and
FACS. In addition, we also determined the effect of the above plasmid expression on the apoptosis of
PC12 cells. Finally, the tissue specificity of TAT-EGFP-HCS in vivo experiments was also examined.
Results:
In the present study, we have constructed a fusion protein with botulinum toxin heavy chain and
a membrane penetrating peptide TAT which can lead the entire molecule through the blood-brain barrier
and reach the central nervous system. Moreover, we also examined the biological activities of this recombinant
biological macromolecule and its physiological effects on nerve cells in vitro and in vivo.
Conclusion:
TAT-EGFP-HSC expressed in vitro has neural guidance function and can carry large proteins
across the cell membrane without influencing the biological activity.
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Affiliation(s)
- Fengjin Hao
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, Liaoning, 110122, China
| | - Yueqin Feng
- Department of Ultrasound, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning, 110001, China
| | - Yifu Guan
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, Liaoning, 110122, China
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11
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Hao F, Feng Y, Guan Y. Light Chain LC and TAT-EGFP-HCS of Botulinum Toxin Expression and Biological Function in vitro and in vivo. CURR PROTEOMICS 2019. [DOI: 10.2174/1570164615666180817100248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Objective: To verify whether the botulinum toxin heavy chain HCS has specific neuronal
targeting function and to confirm whether TAT-EGFP-LC has hydrolyzable SNAP-25 and has transmembrane
biological activity.
Methods:
We constructed the pET-28a-TAT-EGFP-HCS/LC plasmid. After the plasmid is expressed
and purified, we co-cultured it with nerve cells or tumors. In addition, we used Western-Blot to identify
whether protein LC and TAT-EGFP-LC can digest the protein SNAP-25.
Results:
Fluorescence imaging showed that PC12, BV2, C6 and HeLa cells all showed green fluorescence,
and TAT-EGFP-HCS had the strongest fluorescence. Moreover, TAT-EGFP-LC can hydrolyze
intracellular SNAP-25 in PC12 cells, C6 cells, BV2 cells and HeLa, whereas LC alone cannot. In addition,
the in vivo protein TAT-EGFP-HCS can penetrate the blood-brain barrier and enter mouse brain
tissue.
Conclusion:
TAT-EGFP-HSC expressed in vitro has neural guidance function and can carry large proteins
across the cell membrane without influencing the biological activity.
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Affiliation(s)
- Fengjin Hao
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, Liaoning, 110122, China
| | - Yueqin Feng
- Department of Ultrasound, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, 110001, China
| | - Yifu Guan
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, Liaoning, 110122, China
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12
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Neurobiology and therapeutic applications of neurotoxins targeting transmitter release. Pharmacol Ther 2019; 193:135-155. [DOI: 10.1016/j.pharmthera.2018.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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Abstract
Botulinum neurotoxins (BoNTs) and tetanus neurotoxin (TeNT) are the most potent toxins known and cause botulism and tetanus, respectively. BoNTs are also widely utilized as therapeutic toxins. They contain three functional domains responsible for receptor-binding, membrane translocation, and proteolytic cleavage of host proteins required for synaptic vesicle exocytosis. These toxins also have distinct features: BoNTs exist within a progenitor toxin complex (PTC), which protects the toxin and facilitates its absorption in the gastrointestinal tract, whereas TeNT is uniquely transported retrogradely within motor neurons. Our increasing knowledge of these toxins has allowed the development of engineered toxins for medical uses. The discovery of new BoNTs and BoNT-like proteins provides additional tools to understand the evolution of the toxins and to engineer toxin-based therapeutics. This review summarizes the progress on our understanding of BoNTs and TeNT, focusing on the PTC, receptor recognition, new BoNT-like toxins, and therapeutic toxin engineering.
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Affiliation(s)
- Min Dong
- Department of Urology, Boston Children's Hospital, Boston, Massachusetts 02115, USA; .,Department of Microbiology and Immunobiology and Department of Surgery, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden;
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden; .,Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
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14
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Tehran DA, Pirazzini M. Preparation of Cerebellum Granule Neurons from Mouse or Rat Pups and Evaluation of Clostridial Neurotoxin Activity and Their Inhibitors by Western Blot and Immunohistochemistry. Bio Protoc 2018; 8:e2918. [PMID: 34395747 DOI: 10.21769/bioprotoc.2918] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/12/2018] [Accepted: 06/17/2018] [Indexed: 01/29/2023] Open
Abstract
Cerebellar Granule Neurons (CGN) from post-natal rodents have been widely used as a model to study neuronal development, physiology and pathology. CGN cultured in vitro maintain the same features displayed in vivo by mature cerebellar granule cells, including the development of a dense neuritic network, neuronal activity, neurotransmitter release and the expression of neuronal protein markers. Moreover, CGN represent a convenient model for the study of Clostridial Neurotoxins (CNT), most notably known as Tetanus and Botulinum neurotoxins, as they abundantly express both CNT receptors and intraneuronal substrates, i.e., Soluble N-ethylmaleimide-sensitive factor activating protein receptors (SNARE proteins). Here, we describe a protocol for obtaining a highly pure culture of CGN from postnatal rats/mice and an easy procedure for their intoxication with CNT. We also illustrate handy methods to evaluate CNT activity and their inhibition.
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Affiliation(s)
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
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15
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Fonfria E, Elliott M, Beard M, Chaddock JA, Krupp J. Engineering Botulinum Toxins to Improve and Expand Targeting and SNARE Cleavage Activity. Toxins (Basel) 2018; 10:toxins10070278. [PMID: 29973505 PMCID: PMC6071219 DOI: 10.3390/toxins10070278] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/29/2018] [Accepted: 07/01/2018] [Indexed: 12/14/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are highly successful protein therapeutics. Over 40 naturally occurring BoNTs have been described thus far and, of those, only 2 are commercially available for clinical use. Different members of the BoNT family present different biological properties but share a similar multi-domain structure at the molecular level. In nature, BoNTs are encoded by DNA in producing clostridial bacteria and, as such, are amenable to recombinant production through insertion of the coding DNA into other bacterial species. This, in turn, creates possibilities for protein engineering. Here, we review the production of BoNTs by the natural host and also recombinant production approaches utilised in the field. Applications of recombinant BoNT-production include the generation of BoNT-derived domain fragments, the creation of novel BoNTs with improved performance and enhanced therapeutic potential, as well as the advancement of BoNT vaccines. In this article, we discuss site directed mutagenesis, used to affect the biological properties of BoNTs, including approaches to alter their binding to neurons and to alter the specificity and kinetics of substrate cleavage. We also discuss the target secretion inhibitor (TSI) platform, in which the neuronal binding domain of BoNTs is substituted with an alternative cellular ligand to re-target the toxins to non-neuronal systems. Understanding and harnessing the potential of the biological diversity of natural BoNTs, together with the ability to engineer novel mutations and further changes to the protein structure, will provide the basis for increasing the scope of future BoNT-based therapeutics.
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Affiliation(s)
- Elena Fonfria
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK.
| | - Mark Elliott
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK.
| | - Matthew Beard
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK.
| | - John A Chaddock
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK.
| | - Johannes Krupp
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France.
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16
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Webb RP. Engineering of Botulinum Neurotoxins for Biomedical Applications. Toxins (Basel) 2018; 10:toxins10060231. [PMID: 29882791 PMCID: PMC6024800 DOI: 10.3390/toxins10060231] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/01/2018] [Accepted: 06/05/2018] [Indexed: 01/15/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) have been used as therapeutic agents in the clinical treatment of a wide array of neuromuscular and autonomic neuronal transmission disorders. These toxins contain three functional domains that mediate highly specific neuronal cell binding, internalization and cytosolic delivery of proteolytic enzymes that cleave proteins integral to the exocytosis of neurotransmitters. The exceptional cellular specificity, potency and persistence within the neuron that make BoNTs such effective toxins, also make them attractive models for derivatives that have modified properties that could potentially expand their therapeutic repertoire. Advances in molecular biology techniques and rapid DNA synthesis have allowed a wide variety of novel BoNTs with alternative functions to be assessed as potential new classes of therapeutic drugs. This review examines how the BoNTs have been engineered in an effort to produce new classes of therapeutic molecules to address a wide array of disorders.
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Affiliation(s)
- Robert P Webb
- The Division of Molecular and Translational Sciences, United States Army Medical Research Institute for Infectious Diseases, Fort Detrick, MD 21702, USA.
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17
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Tehran DA, Pirazzini M. Novel Botulinum Neurotoxins: Exploring Underneath the Iceberg Tip. Toxins (Basel) 2018; 10:toxins10050190. [PMID: 29748471 PMCID: PMC5983246 DOI: 10.3390/toxins10050190] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/05/2018] [Accepted: 05/08/2018] [Indexed: 12/26/2022] Open
Abstract
Botulinum neurotoxins (BoNTs), the etiological agents of botulism, are the deadliest toxins known to humans. Yet, thanks to their biological and toxicological features, BoNTs have become sophisticated tools to study neuronal physiology and valuable therapeutics for an increasing number of human disorders. BoNTs are produced by multiple bacteria of the genus Clostridium and, on the basis of their different immunological properties, were classified as seven distinct types of toxin. BoNT classification remained stagnant for the last 50 years until, via bioinformatics and high-throughput sequencing techniques, dozens of BoNT variants, novel serotypes as well as BoNT-like toxins within non-clostridial species have been discovered. Here, we discuss how the now “booming field” of botulinum neurotoxin may shed light on their evolutionary origin and open exciting avenues for future therapeutic applications.
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Affiliation(s)
- Domenico Azarnia Tehran
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy.
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy.
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18
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Haywood EE, Ho M, Wilson BA. Modular domain swapping among the bacterial cytotoxic necrotizing factor (CNF) family for efficient cargo delivery into mammalian cells. J Biol Chem 2018; 293:3860-3870. [PMID: 29371399 DOI: 10.1074/jbc.ra117.001381] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/11/2018] [Indexed: 11/06/2022] Open
Abstract
Modular AB-type bacterial protein toxins target mammalian host cells with high specificity and deliver their toxic cargo into the cytosol. Hence, these toxins are being explored as agents for targeted cytosolic delivery in biomedical and research applications. The cytotoxic necrotizing factor (CNF) family is unique among these toxins in that their homologous sequences are found in a wide array of bacteria, and their activity domains are packaged in various delivery systems. Here, to study how CNF cargo and delivery modules can be assembled for efficient cytosolic delivery, we generated chimeric toxins by swapping functional domains among CNF1, CNF2, CNF3, and CNFy. Chimeras with a CNFy delivery vehicle were more stably expressed, but were less efficient at cargo delivery into HEK293-T cells. We also found that CNFy cargo is the most universally compatible and that CNF3 delivery vehicle is the most flexible and efficient at delivering cargo. These findings suggest that domains within proteins can be swapped and accommodate each other for efficient function and that an individual domain could be engineered for compatibility with multiple partner domains. We anticipate that our insights could help inform chemical biology approaches to develop toxin-based cargo-delivery platforms for cytosolic cargo delivery of therapeutics or molecular probes into mammalian cells.
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Affiliation(s)
- Elizabeth E Haywood
- From the Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
| | - Mengfei Ho
- From the Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
| | - Brenda A Wilson
- From the Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
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19
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Larabee JL, Hauck GD, Ballard JD. Cell-penetrating peptides derived from Clostridium difficile TcdB2 and a related large clostridial toxin. J Biol Chem 2017; 293:1810-1819. [PMID: 29247010 DOI: 10.1074/jbc.m117.815373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/12/2017] [Indexed: 12/15/2022] Open
Abstract
Clostridium difficile TcdB (2366 amino acid residues) is an intracellular bacterial toxin that binds to cells and enters the cytosol where it glucosylates small GTPases. In the current study, we examined a putative cell entry region of TcdB (amino acid residues 1753-1851) for short sequences that function as cell-penetrating peptides (CPPs). To screen for TcdB-derived CPPs, a panel of synthetic peptides was tested for the ability to enhance transferrin (Tf) association with cells. Four candidate CPPs were discovered, and further study on one peptide (PepB2) pinpointed an asparagine residue necessary for CPP activity. PepB2 mediated the cell entry of a wide variety of molecules including dextran, streptavidin, microspheres, and lentivirus particles. Of note, this uptake was dramatically reduced in the presence of the Na+/H+ exchange blocker and micropinocytosis inhibitor amiloride, suggesting that PepB2 invokes macropinocytosis. Moreover, we found that PepB2 had more efficient cell-penetrating activity than several other well-known CPPs (TAT, penetratin, Pep-1, and TP10). Finally, Tf assay-based screening of peptides derived from two other large clostridial toxins, TcdA and TcsL, uncovered two new TcdA-derived CPPs. In conclusion, we have identified six CPPs from large clostridial toxins and have demonstrated the ability of PepB2 to promote cell association and entry of several molecules through a putative fluid-phase macropinocytotic mechanism.
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Affiliation(s)
- Jason L Larabee
- From the Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Garrett D Hauck
- From the Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Jimmy D Ballard
- From the Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
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20
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Zanetti G, Sikorra S, Rummel A, Krez N, Duregotti E, Negro S, Henke T, Rossetto O, Binz T, Pirazzini M. Botulinum neurotoxin C mutants reveal different effects of syntaxin or SNAP-25 proteolysis on neuromuscular transmission. PLoS Pathog 2017; 13:e1006567. [PMID: 28800600 PMCID: PMC5568444 DOI: 10.1371/journal.ppat.1006567] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/23/2017] [Accepted: 08/03/2017] [Indexed: 11/30/2022] Open
Abstract
Botulinum neurotoxin serotype C (BoNT/C) is a neuroparalytic toxin associated with outbreaks of animal botulism, particularly in birds, and is the only BoNT known to cleave two different SNARE proteins, SNAP-25 and syntaxin. BoNT/C was shown to be a good substitute for BoNT/A1 in human dystonia therapy because of its long lasting effects and absence of neuromuscular damage. Two triple mutants of BoNT/C, namely BoNT/C S51T/R52N/N53P (BoNT/C α-51) and BoNT/C L200W/M221W/I226W (BoNT/C α-3W), were recently reported to selectively cleave syntaxin and have been used here to evaluate the individual contribution of SNAP-25 and syntaxin cleavage to the effect of BoNT/C in vivo. Although BoNT/C α-51 and BoNT/C α-3W toxins cleave syntaxin with similar efficiency, we unexpectedly found also cleavage of SNAP-25, although to a lesser extent than wild type BoNT/C. Interestingly, the BoNT/C mutants exhibit reduced lethality compared to wild type toxin, a result that correlated with their residual activity against SNAP-25. In spite of this, a local injection of BoNT/C α-51 persistently impairs neuromuscular junction activity. This is due to an initial phase in which SNAP-25 cleavage causes a complete blockade of neurotransmission, and to a second phase of incomplete impairment ascribable to syntaxin cleavage. Together, these results indicate that neuroparalysis of BoNT/C at the neuromuscular junction is due to SNAP-25 cleavage, while the proteolysis of syntaxin provides a substantial, but incomplete, neuromuscular impairment. In light of this evidence, we discuss a possible clinical use of BoNT/C α-51 as a botulinum neurotoxin endowed with a wide safety margin and a long lasting effect. The seven established Botulinum Neurotoxins serotypes (BoNT/A to G) and the many BoNT subtypes, the causative agents of botulism, are the most poisonous substances known (lethal doses in the low ng/kg range). Due to their toxicological properties, BoNTs are Janus-faced toxins: potent pathogenic factors and potential bioterrorism agents as well as safe and efficacious therapeutics. BoNTs exert their neuroparalytic action by cleaving SNARE proteins, either SNAP-25 or synaptobrevin/VAMP, which mediate neurotransmitter release at the neuromuscular junction; BoNT/C is the only serotype shown to cleave SNAP-25 and syntaxin-1 in vitro. Our study shows for the first time that this parallel cleavage also occurs in vivo. By using mutated toxins reported to be syntaxin-selective, we found that SNAP-25 proteolysis at the neuromuscular junction is the key determinant of BoNT/C lethality as it completely blocks nerve-muscle transmission. Conversely, syntaxin-1 cleavage only attenuates nerve terminal activity without inactivating the synapse, leading to only a partial decrease of neuromuscular functionality. As a result, the BoNT/C mutants have dramatically reduced lethality, but still modulate neuromuscular junction activity upon intramuscular injection. This aspect is particularly relevant considering the possible use of syntaxin-specific BoNT/C derivatives to improve the present clinical utilization of BoNTs.
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Affiliation(s)
- Giulia Zanetti
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Stefan Sikorra
- Institut für Zellbiochemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Nadja Krez
- Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Elisa Duregotti
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Samuele Negro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Tina Henke
- Institut für Zellbiochemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Ornella Rossetto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Thomas Binz
- Institut für Zellbiochemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- * E-mail:
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21
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Bruce VJ, McNaughton BR. Inside Job: Methods for Delivering Proteins to the Interior of Mammalian Cells. Cell Chem Biol 2017; 24:924-934. [DOI: 10.1016/j.chembiol.2017.06.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/19/2017] [Accepted: 06/27/2017] [Indexed: 10/19/2022]
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22
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Pirazzini M, Rossetto O, Eleopra R, Montecucco C. Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology. Pharmacol Rev 2017; 69:200-235. [PMID: 28356439 PMCID: PMC5394922 DOI: 10.1124/pr.116.012658] [Citation(s) in RCA: 410] [Impact Index Per Article: 58.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The study of botulinum neurotoxins (BoNT) is rapidly progressing in many aspects.
Novel BoNTs are being discovered owing to next generation sequencing, but their
biologic and pharmacological properties remain largely unknown. The molecular
structure of the large protein complexes that the toxin forms with accessory
proteins, which are included in some BoNT type A1 and B1 pharmacological
preparations, have been determined. By far the largest effort has been dedicated to
the testing and validation of BoNTs as therapeutic agents in an ever increasing
number of applications, including pain therapy. BoNT type A1 has been also exploited
in a variety of cosmetic treatments, alone or in combination with other agents, and
this specific market has reached the size of the one dedicated to the treatment of
medical syndromes. The pharmacological properties and mode of action of BoNTs have
shed light on general principles of neuronal transport and protein-protein
interactions and are stimulating basic science studies. Moreover, the wide array of
BoNTs discovered and to be discovered and the production of recombinant BoNTs endowed
with specific properties suggest novel uses in therapeutics with increasing
disease/symptom specifity. These recent developments are reviewed here to provide an
updated picture of the biologic mechanism of action of BoNTs, of their increasing use
in pharmacology and in cosmetics, and of their toxicology.
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Affiliation(s)
- Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Italy (M.P., O.R., C.M.); Neurologic Department, University-Hospital S. Maria della Misericordia, Udine, Italy (R.E.); and Consiglio Nazionale delle Ricerche, Institute of Neuroscience, University of Padova, Italy (C.M.)
| | - Ornella Rossetto
- Department of Biomedical Sciences, University of Padova, Italy (M.P., O.R., C.M.); Neurologic Department, University-Hospital S. Maria della Misericordia, Udine, Italy (R.E.); and Consiglio Nazionale delle Ricerche, Institute of Neuroscience, University of Padova, Italy (C.M.)
| | - Roberto Eleopra
- Department of Biomedical Sciences, University of Padova, Italy (M.P., O.R., C.M.); Neurologic Department, University-Hospital S. Maria della Misericordia, Udine, Italy (R.E.); and Consiglio Nazionale delle Ricerche, Institute of Neuroscience, University of Padova, Italy (C.M.)
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Italy (M.P., O.R., C.M.); Neurologic Department, University-Hospital S. Maria della Misericordia, Udine, Italy (R.E.); and Consiglio Nazionale delle Ricerche, Institute of Neuroscience, University of Padova, Italy (C.M.)
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23
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Vazquez-Cintron EJ, Beske PH, Tenezaca L, Tran BQ, Oyler JM, Glotfelty EJ, Angeles CA, Syngkon A, Mukherjee J, Kalb SR, Band PA, McNutt PM, Shoemaker CB, Ichtchenko K. Engineering Botulinum Neurotoxin C1 as a Molecular Vehicle for Intra-Neuronal Drug Delivery. Sci Rep 2017; 7:42923. [PMID: 28220863 PMCID: PMC5318933 DOI: 10.1038/srep42923] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 01/16/2017] [Indexed: 12/21/2022] Open
Abstract
Botulinum neurotoxin (BoNT) binds to and internalizes its light chain into presynaptic compartments with exquisite specificity. While the native toxin is extremely lethal, bioengineering of BoNT has the potential to eliminate toxicity without disrupting neuron-specific targeting, thereby creating a molecular vehicle capable of delivering therapeutic cargo into the neuronal cytosol. Building upon previous work, we have developed an atoxic derivative (ad) of BoNT/C1 through rationally designed amino acid substitutions in the metalloprotease domain of wild type (wt) BoNT/C1. To test if BoNT/C1 ad retains neuron-specific targeting without concomitant toxic host responses, we evaluated the localization, activity, and toxicity of BoNT/C1 ad in vitro and in vivo. In neuronal cultures, BoNT/C1 ad light chain is rapidly internalized into presynaptic compartments, but does not cleave SNARE proteins nor impair spontaneous neurotransmitter release. In mice, systemic administration resulted in the specific co-localization of BoNT/C1 ad with diaphragmatic motor nerve terminals. The mouse LD50 of BoNT/C1 ad is 5 mg/kg, with transient neurological symptoms emerging at sub-lethal doses. Given the low toxicity and highly specific neuron-targeting properties of BoNT/C1 ad, these data suggest that BoNT/C1 ad can be useful as a molecular vehicle for drug delivery to the neuronal cytoplasm.
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Affiliation(s)
- Edwin J Vazquez-Cintron
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA.,CytoDel LLC, New York, NY, 10027, USA.,The United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Phillip H Beske
- The United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Luis Tenezaca
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA.,CytoDel LLC, New York, NY, 10027, USA
| | - Bao Q Tran
- Excet, Inc., 6225 Brandon Ave., Suite 360, Springfield, VA, 22150, USA
| | - Jonathan M Oyler
- The United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Elliot J Glotfelty
- The United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Christopher A Angeles
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Aurelia Syngkon
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Jean Mukherjee
- Department of Infectious Diseases and Global Health, Tufts University Clinical and Translational Science Institute, North Grafton, MA, 01536, USA
| | - Suzanne R Kalb
- Centers for Disease Control and Prevention, National Center for Environmental Health/Agency for Toxic Substances and Disease Registry, Atlanta, GA 30341, USA
| | - Philip A Band
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA.,CytoDel LLC, New York, NY, 10027, USA.,Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, New York, NY, 10016, USA
| | - Patrick M McNutt
- The United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Charles B Shoemaker
- Department of Infectious Diseases and Global Health, Tufts University Clinical and Translational Science Institute, North Grafton, MA, 01536, USA
| | - Konstantin Ichtchenko
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
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Ovsepian SV, O'Leary VB, Ntziachristos V, Dolly JO. Circumventing Brain Barriers: Nanovehicles for Retroaxonal Therapeutic Delivery. Trends Mol Med 2016; 22:983-993. [PMID: 27720365 DOI: 10.1016/j.molmed.2016.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 02/06/2023]
Abstract
In addition to safeguarding the central nervous system (CNS) from the vast majority of pathogens and toxins, transvascular barriers impose immense challenges to the delivery of beneficial cargo. A few toxins and neurotropic viruses capable of penetrating the brain have proved to be potentially valuable for neuron targeting and enhanced transfer of restorative medicine and therapeutic genes. Here we review molecular concepts and implications of the highly neurotropic tetanus toxin (TeTx) and botulinum neurotoxins (BoNTs) and their ability to infiltrate and migrate throughout neurons. We discuss recent applications of their detoxified variants as versatile nanovehicles for retroaxonal delivery of therapeutics to motor neurons and synapses. Continued advances in research on these remarkable agents in preclinical trials might facilitate their future use for medical benefit.
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Affiliation(s)
- Saak V Ovsepian
- Institute for Biological and Medical Imaging, Helmholtz Zentrum Munich, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany; Munich School of Bioengineering, Technical University Munich, 81675 Munich, Germany; International Centre for Neurotherapeutics, Dublin City University, Dublin 9, Ireland.
| | - Valerie B O'Leary
- Institute of Radiation Biology, Helmholtz Zentrum Munich, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Vasilis Ntziachristos
- Institute for Biological and Medical Imaging, Helmholtz Zentrum Munich, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany; Munich School of Bioengineering, Technical University Munich, 81675 Munich, Germany
| | - J Oliver Dolly
- International Centre for Neurotherapeutics, Dublin City University, Dublin 9, Ireland
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25
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Azarnia Tehran D, Pirazzini M, Leka O, Mattarei A, Lista F, Binz T, Rossetto O, Montecucco C. Hsp90 is involved in the entry of clostridial neurotoxins into the cytosol of nerve terminals. Cell Microbiol 2016; 19. [DOI: 10.1111/cmi.12647] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/06/2016] [Accepted: 07/08/2016] [Indexed: 12/31/2022]
Affiliation(s)
- Domenico Azarnia Tehran
- Department of Biomedical Sciences; University of Padova; Via Ugo Bassi 58/B 35121 Padova Italy
| | - Marco Pirazzini
- Department of Biomedical Sciences; University of Padova; Via Ugo Bassi 58/B 35121 Padova Italy
| | - Oneda Leka
- Department of Biomedical Sciences; University of Padova; Via Ugo Bassi 58/B 35121 Padova Italy
| | - Andrea Mattarei
- Department of Chemical Sciences; University of Padova; Via F. Marzolo 1 35131 Padova Italy
| | - Florigio Lista
- Histology and Molecular Biology Section; Army Medical and Veterinary Research Center; Via Santo Stefano Rotondo 4 00184 Rome Italy
| | - Thomas Binz
- Medizinische Hochschule Hannover; Institut für Physiologische Chemie OE4310; 30625 Hannover Germany
| | - Ornella Rossetto
- Department of Biomedical Sciences; University of Padova; Via Ugo Bassi 58/B 35121 Padova Italy
| | - Cesare Montecucco
- Department of Biomedical Sciences; University of Padova; Via Ugo Bassi 58/B 35121 Padova Italy
- National Research Institute of Neuroscience; University of Padova; Via Ugo Bassi 58/B 35121 Padova Italy
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26
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Hansbauer EM, Skiba M, Endermann T, Weisemann J, Stern D, Dorner MB, Finkenwirth F, Wolf J, Luginbühl W, Messelhäußer U, Bellanger L, Woudstra C, Rummel A, Fach P, Dorner BG. Detection, differentiation, and identification of botulinum neurotoxin serotypes C, CD, D, and DC by highly specific immunoassays and mass spectrometry. Analyst 2016; 141:5281-97. [PMID: 27353114 DOI: 10.1039/c6an00693k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Botulinum neurotoxin (BoNT) serotypes C and D and their mosaic variants CD and DC cause severe cases of botulism in animal husbandry and wildlife. Epidemiological data on the exact serotype or toxin variant causing outbreaks are rarely available, mainly because of their high sequence identity and the lack of fast and specific screening tools to detect and differentiate the four similar toxins. To fill this gap, we developed four highly specific sandwich enzyme-linked immunosorbent assays (ELISAs) able to detect and differentiate botulinum neurotoxins type BoNT/C, D, CD, and DC based on four distinct combinations of specific monoclonal antibodies targeting both conserved and divergent subdomains of the four toxins. Here, highly sensitive detection with detection limits between 2 and 24 pg mL(-1) was achieved. The ELISAs were extensively validated and results were compared with data obtained by quantitative real-time PCR using a panel of Clostridium botulinum strains, real sample materials from veterinary botulism outbreaks, and non-BoNT-producing Clostridia. Additionally, in order to verify the results obtained by ELISA screening, the new monoclonal antibodies were used for BoNT enrichment and subsequent detection (i) on a functional level by endopeptidase mass spectrometry (Endopep-MS) assays and (ii) on a protein sequence level by LC-MS/MS spectrometry. Based on all technical information gathered in the validation study, the four differentiating ELISAs turned out to be highly reliable screening tools for the rapid analysis of veterinary botulism cases and should aid future field investigations of botulism outbreaks and the acquisition of epidemiological data.
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Affiliation(s)
- Eva-Maria Hansbauer
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute (RKI), Berlin, Germany.
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27
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Zuverink M, Barbieri JT. From GFP to β-lactamase: advancing intact cell imaging for toxins and effectors. Pathog Dis 2015; 73:ftv097. [PMID: 26500183 DOI: 10.1093/femspd/ftv097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 11/13/2022] Open
Abstract
Canonical reporters such as green fluorescent protein (GFP) and luciferase have assisted researchers in probing cellular pathways and processes. Prior research in pathogenesis depended on sensitivity of biochemical and biophysical techniques to identify effectors and elucidate entry mechanisms. Recently, the β-lactamase (βlac) reporter system has advanced toxin and effector reporting by permitting measurement of βlac delivery into the cytosol or host βlac expression in intact cells. βlac measurement in cells was facilitated by the development of the fluorogenic substrate, CCF2-AM, to identify novel effectors, target cells, and domains involved in bacterial pathogenesis. The assay is also adaptable for high-throughput screening of small molecule inhibitors against toxins, providing information on mechanism and potential therapeutic agents. The versatility and limitations of the βlac reporter system as applied to toxins and effectors are discussed in this review.
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Affiliation(s)
- Madison Zuverink
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI 53226, USA
| | - Joseph T Barbieri
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI 53226, USA
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28
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Zanetti G, Azarnia Tehran D, Pirazzini M, Binz T, Shone CC, Fillo S, Lista F, Rossetto O, Montecucco C. Inhibition of botulinum neurotoxins interchain disulfide bond reduction prevents the peripheral neuroparalysis of botulism. Biochem Pharmacol 2015; 98:522-30. [PMID: 26449594 DOI: 10.1016/j.bcp.2015.09.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 09/29/2015] [Indexed: 12/18/2022]
Abstract
Botulinum neurotoxins (BoNTs) form a growing family of metalloproteases with a unique specificity either for VAMP, SNAP25 or syntaxin. The BoNTs are grouped in seven different serotypes indicated by letters from A to G. These neurotoxins enter the cytosol of nerve terminals via a 100 kDa chain which binds to the presynaptic membrane and assists the translocation of a 50 kDa metalloprotease chain. These two chains are linked by a single disulfide bridge which plays an essential role during the entry of the metalloprotease chain in the cytosol, but thereafter it has to be reduced to free the proteolytic activity. Its reduction is mediated by thioredoxin which is continuously regenerated by its reductase. Here we show that inhibitors of thioredoxin reductase or of thioredoxin prevent the specific proteolysis of VAMP by the four VAMP-specific BoNTs: type B, D, F and G. These compounds are effective not only in primary cultures of neurons, but also in preventing the in vivo mouse limb neuroparalysis. In addition, one of these inhibitors, Ebselen, largely protects mice from the death caused by a systemic injection. Together with recent results obtained with BoNTs specific for SNAP25 and syntaxin, the present data demonstrate the essential role of the thioredoxin-thioredoxin reductase system in reducing the interchain disulfide during the nerve intoxication mechanism of all serotypes. Therefore its inhibitors should be considered for a possible use to prevent botulism and for treating infant botulism.
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Affiliation(s)
- Giulia Zanetti
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Domenico Azarnia Tehran
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Marcon Pirazzini
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Thomas Binz
- Institut für Biochemie, OE 4310, Medizinische Hochschule Hannover, 30623 Hannover, Germany
| | - Clifford C Shone
- Public Health England, Porton Down, Salisbury, Wiltshire SP4 OJG, UK
| | - Silvia Fillo
- Histology and Molecular Biology Section, Army Medical and Veterinary Research Center, Via Santo Stefano Rotondo 4, 00184 Rome, Italy
| | - Florigio Lista
- Histology and Molecular Biology Section, Army Medical and Veterinary Research Center, Via Santo Stefano Rotondo 4, 00184 Rome, Italy
| | - Ornella Rossetto
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy; Istituto CNR di Neuroscienze, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
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29
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Kostrzewa RM, Kostrzewa RA, Kostrzewa JP. Botulinum neurotoxin: Progress in negating its neurotoxicity; and in extending its therapeutic utility via molecular engineering. MiniReview. Peptides 2015; 72:80-7. [PMID: 26192475 DOI: 10.1016/j.peptides.2015.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 07/01/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022]
Abstract
While the poisonous effects of botulinum neurotoxin (BoNT) have been recognized since antiquity, the overall actions and mechanisms of effects of BoNT have been elucidated primarily over the past several decades. The general utility of BoNT is described in the paper, but the focus is mainly on the approaches towards negating the toxic effects of BoNT, and on the projection of an engineered BoNT molecule serving as a Trojan Horse to deliver a therapeutic load for treatment of a host of medical disorders. The BoNT molecule is configured with a binding domain, a zinc-dependent protease with specificity primarily for vesicular proteins, and a translocation domain for delivery of the metalloprotease into the cytoplasm. The anti-toxin approaches for BoNT include the use of vaccines, antibodies, block of BoNT binding or translocation, inhibition of metalloprotease activity, impeded translocation of the protease/catalytic domain, and inhibition of the downstream Src signaling pathway. Projections of BoNT as a therapeutic include its targeting to non-cholinergic nerves, also targeting to non-neuronal cells for treatment of hypersecretory disorders (e.g., cystic fibrosis), and treatment of hormonal disorders (e.g., acromegaly). Still in the exploratory phase, there is the expectation of major advances in BoNT neuroprotective strategies and burgeoning utility of engineered BoNTs as therapeutics.
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Affiliation(s)
- Richard M Kostrzewa
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, P.O. Box 70577, Johnson City, TN 37614, USA.
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30
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On the translocation of botulinum and tetanus neurotoxins across the membrane of acidic intracellular compartments. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:467-74. [PMID: 26307528 DOI: 10.1016/j.bbamem.2015.08.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 08/04/2015] [Accepted: 08/17/2015] [Indexed: 01/25/2023]
Abstract
Tetanus and botulinum neurotoxins are produced by anaerobic bacteria of the genus Clostridium and are the most poisonous toxins known, with 50% mouse lethal dose comprised within the range of 0.1-few nanograms per Kg, depending on the individual toxin. Botulinum neurotoxins are similarly toxic to humans and can therefore be considered for potential use in bioterrorism. At the same time, their neurospecificity and reversibility of action make them excellent therapeutics for a growing and heterogeneous number of human diseases that are characterized by a hyperactivity of peripheral nerve terminals. The complete crystallographic structure is available for some botulinum toxins, and reveals that they consist of four domains functionally related to the four steps of their mechanism of neuron intoxication: 1) binding to specific receptors of the presynaptic membrane; 2) internalization via endocytic vesicles; 3) translocation across the membrane of endocytic vesicles into the neuronal cytosol; 4) catalytic activity of the enzymatic moiety directed towards the SNARE proteins. Despite the many advances in understanding the structure-mechanism relationship of tetanus and botulinum neurotoxins, the molecular events involved in the translocation step have been only partially elucidated. Here we will review recent advances that have provided relevant insights on the process and discuss possible models that can be experimentally tested. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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31
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Pellett S, Tepp WH, Scherf JM, Johnson EA. Botulinum Neurotoxins Can Enter Cultured Neurons Independent of Synaptic Vesicle Recycling. PLoS One 2015; 10:e0133737. [PMID: 26207366 PMCID: PMC4514655 DOI: 10.1371/journal.pone.0133737] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 06/15/2015] [Indexed: 11/25/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the causative agent of the severe and long-lasting disease botulism. At least seven different serotypes of BoNTs (denoted A-G) have been described. All BoNTs enter human or animal neuronal cells via receptor mediated endocytosis and cleave cytosolic SNARE proteins, resulting in a block of synaptic vesicle exocytosis, leading to the flaccid paralysis characteristic of botulism. Previous data have indicated that once a neuronal cell has been intoxicated by a BoNT, further entry of the same or other BoNTs is prevented due to disruption of synaptic vesicle recycling. However, it has also been shown that cultured neurons exposed to BoNT/A are still capable of taking up BoNT/E. In this report we show that in general BoNTs can enter cultured human or mouse neuronal cells that have previously been intoxicated with another BoNT serotype. Quantitative analysis of cell entry by assessing SNARE cleavage revealed none or only a minor difference in the efficiency of uptake of BoNTs into previously intoxicated neurons. Examination of the endocytic entry pathway by specific endocytosis inhibitors indicated that BoNTs are taken up by clathrin coated pits in both non pre-exposed and pre-exposed neurons. LDH release assays indicated that hiPSC derived neurons exposed consecutively to two different BoNT serotypes remained viable and healthy except in the case of BoNT/E or combinations of BoNT/E with BoNT/B, /D, or /F. Overall, our data indicate that previous intoxication of neuronal cells with BoNT does not inhibit further uptake of BoNTs.
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Affiliation(s)
- Sabine Pellett
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States of America
| | - William H. Tepp
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States of America
| | - Jacob M. Scherf
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States of America
| | - Eric A. Johnson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States of America
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32
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From naturally-occurring neurotoxic agents to CNS shuttles for drug delivery. Eur J Pharm Sci 2015; 74:63-76. [DOI: 10.1016/j.ejps.2015.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/19/2015] [Accepted: 04/08/2015] [Indexed: 12/20/2022]
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Pellett S, Tepp WH, Scherf JM, Pier CL, Johnson EA. Activity of botulinum neurotoxin type D (strain 1873) in human neurons. Toxicon 2015; 101:63-9. [PMID: 25937339 DOI: 10.1016/j.toxicon.2015.04.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/24/2015] [Accepted: 04/29/2015] [Indexed: 11/28/2022]
Abstract
Botulinum Neurotoxin type D (BoNT/D) causes periodic outbreaks of botulism in cattle and horses, but is rarely associated with human botulism. Previous studies have shown that humans responded poorly to peripheral injection of up to 10U of BoNT/D. Isolated human pyramidalis muscle preparations were resistant to BoNT/D, whereas isolated human intercostal muscle preparations responded to BoNT/D similarly as to other BoNT serotypes. In vitro data indicate that BoNT/D does not cleave human VAMP1 efficiently, and differential expression of the VAMP 1 and 2 isoforms may be responsible for the above observations. Here we examined sensitivity of cultured human neurons derived from human induced pluripotent stem cells to BoNT/D. Our data indicate that BoNT/D can enter and cleave VAMP 2 in human neurons, but at significantly lower efficiency than other BoNT serotypes. In addition, BoNT/D had a short duration of action in the cultured neurons, similar to that of BoNT/E. In vivo analyses indicated a slower time to death in mice, as well as a later onset and shorter duration of action than BoNT/A1. Finally, examination of BoNT/D activity in various rodent and human cell models resulted in dramatic differences in sensitivity, indicating a unique cell entry mechanism of BoNT/D.
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Affiliation(s)
- Sabine Pellett
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - William H Tepp
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Jacob M Scherf
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Christina L Pier
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Eric A Johnson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
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34
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A Heterologous Reporter Defines the Role of the Tetanus Toxin Interchain Disulfide in Light-Chain Translocation. Infect Immun 2015; 83:2714-24. [PMID: 25895970 DOI: 10.1128/iai.00477-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 04/13/2015] [Indexed: 11/20/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) and tetanus toxin (TeNT) are the most potent toxins for humans and elicit unique pathologies due to their ability to traffic within motor neurons. BoNTs act locally within motor neurons to elicit flaccid paralysis, while retrograde TeNT traffics to inhibitory neurons within the central nervous system (CNS) to elicit spastic paralysis. BoNT and TeNT are dichain proteins linked by an interchain disulfide bond comprised of an N-terminal catalytic light chain (LC) and a C-terminal heavy chain (HC) that encodes an LC translocation domain (HCT) and a receptor-binding domain (HCR). LC translocation is the least understood property of toxin action, but it involves low pH, proteolysis, and an intact interchain disulfide bridge. Recently, Pirazzini et al. (FEBS Lett 587:150-155, 2013, http://dx.doi.org/10.1016/j.febslet.2012.11.007) observed that inhibitors of thioredoxin reductase (TrxR) blocked TeNT and BoNT action in cerebellar granular neurons. In the current study, an atoxic TeNT LC translocation reporter was engineered by fusing β-lactamase to the N terminus of TeNT [βlac-TeNT(RY)] to investigate LC translocation in primary cortical neurons and Neuro-2a cells. βlac-TeNT(RY) retained the interchain disulfide bond, showed ganglioside-dependent binding to neurons, required acidification to promote βlac translocation, and was sensitive to auranofin, an inhibitor of thioredoxin reductase. Mutation of βlac-TeNT(RY) at C439S and C467S eliminated the interchain disulfide bond and inhibited βlac translocation. These data support the requirement of an intact interchain disulfide for LC translocation and imply that disulfide reduction is a prerequisite for LC delivery into the host cytosol. The data also support a model that LC translocation proceeds from the C to the N terminus. βlac-TeNT(RY) is the first reporter system to measure translocation by an AB single-chain toxin in intact cells.
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35
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Engineering therapeutic proteins for cell entry: the natural approach. Trends Biotechnol 2015; 33:163-71. [DOI: 10.1016/j.tibtech.2014.12.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/08/2014] [Accepted: 12/16/2014] [Indexed: 02/04/2023]
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36
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Scherf JM, Hu XS, Tepp WH, Ichtchenko K, Johnson EA, Pellett S. Analysis of gene expression in induced pluripotent stem cell-derived human neurons exposed to botulinum neurotoxin A subtype 1 and a type A atoxic derivative. PLoS One 2014; 9:e111238. [PMID: 25337697 PMCID: PMC4206481 DOI: 10.1371/journal.pone.0111238] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/19/2014] [Indexed: 11/18/2022] Open
Abstract
Botulinum neurotoxin type A1 (BoNT/A1) is a potent protein toxin responsible for the potentially fatal human illness botulism. Notwithstanding, the long-lasting flaccid muscle paralysis caused by BoNT/A has led to its utility as a powerful and versatile bio-pharmaceutical. The flaccid paralysis is due to specific cleavage of neuronal SNAREs by BoNTs. However, actions of BoNTs on intoxicated neurons besides the cleavage of SNAREs have not been studied in detail. In this study we investigated by microarray analysis the effects of BoNT/A and a catalytically inactive derivative (BoNT/A ad) on the transcriptome of human induced pluripotent stem cell (hiPSC)-derived neurons at 2 days and 2 weeks after exposure. While there were only minor changes in expression levels at 2 days post exposure, at 2 weeks post exposure 492 genes were differentially expressed more than 2-fold in BoNT/A1-exposed cells when compared to non-exposed populations, and 682 genes were differentially expressed in BoNT/A ad-exposed cells. The vast majority of genes were similarly regulated in BoNT/A1 and BoNT/A ad-exposed neurons, and the few genes differentially regulated between BoNT/A1 and BoNT/A ad-exposed neurons were differentially expressed less than 3.5 fold. These data indicate a similar response of neurons to BoNT/A1 and BoNT/A ad exposure. The most highly regulated genes in cells exposed to either BoNT/A1 or BoNT/A ad are involved in neurite outgrowth and calcium channel sensitization.
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Affiliation(s)
- Jacob M. Scherf
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Xiaoyang Serene Hu
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - William H. Tepp
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Konstantin Ichtchenko
- Department of Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Eric A. Johnson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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Rossetto O, Pirazzini M, Montecucco C. Botulinum neurotoxins: genetic, structural and mechanistic insights. Nat Rev Microbiol 2014; 12:535-49. [PMID: 24975322 DOI: 10.1038/nrmicro3295] [Citation(s) in RCA: 378] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Botulinum neurotoxins (BoNTs) are produced by anaerobic bacteria of the genus Clostridium and cause a persistent paralysis of peripheral nerve terminals, which is known as botulism. Neurotoxigenic clostridia belong to six phylogenetically distinct groups and produce more than 40 different BoNT types, which inactivate neurotransmitter release owing to their metalloprotease activity. In this Review, we discuss recent studies that have improved our understanding of the genetics and structure of BoNT complexes. We also describe recent insights into the mechanisms of BoNT entry into the general circulation, neuronal binding, membrane translocation and neuroparalysis.
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Affiliation(s)
- Ornella Rossetto
- 1] Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [2] National Research Council Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [3]
| | - Marco Pirazzini
- 1] Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [2] National Research Council Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [3]
| | - Cesare Montecucco
- 1] Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. [2] National Research Council Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy
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Mazzocchio R, Caleo M. More than at the neuromuscular synapse: actions of botulinum neurotoxin A in the central nervous system. Neuroscientist 2014; 21:44-61. [PMID: 24576870 DOI: 10.1177/1073858414524633] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Botulinum neurotoxin type A (BoNT/A) is a metalloprotease that produces a sustained yet transitory blockade of transmitter release from peripheral nerve terminals. Local delivery of this neurotoxin is successfully employed in clinical practice to reduce muscle hyperactivity such as in spasticity and dystonia, and to relieve pain with long-lasting therapeutic effects. However, not all BoNT/A effects can be explained by an action at peripheral nerve terminals. Indeed, it appears that BoNT/A is endowed with trafficking properties similar to the parental tetanus neurotoxin and thus be able to directly affect the CNS. In this review, we present and discuss novel compelling evidence for a direct central effect of BoNT/A in both dorsal and ventral horns of the animal and human spinal cord after peripheral injection of the neurotoxin, with important consequences on pain and motor control. This new knowledge is expected to radically change the approach to the use of BoNT/A in the future. As BoNT/A central action appears to also contribute to functional improvement, for instance in human spastic gait, the challenge will be to develop new subtypes or BoNT derivatives with deliberate, cell-specific central effects in order to fully exploit the spectrum of BoNT/A therapeutic activity.
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Affiliation(s)
- Riccardo Mazzocchio
- S.C. Neurologia e Neurofisiologia Clinica, Dipartimento di Scienze Neurologiche e Neurosensoriali, Azienda Ospedaliera Universitaria Senese, Viale Bracci, Siena, Italy
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Vazquez-Cintron EJ, Vakulenko M, Band PA, Stanker LH, Johnson EA, Ichtchenko K. Atoxic derivative of botulinum neurotoxin A as a prototype molecular vehicle for targeted delivery to the neuronal cytoplasm. PLoS One 2014; 9:e85517. [PMID: 24465585 PMCID: PMC3899041 DOI: 10.1371/journal.pone.0085517] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 11/27/2013] [Indexed: 12/31/2022] Open
Abstract
We have previously described genetic constructs and expression systems that enable facile production of recombinant derivatives of botulinum neurotoxins (BoNTs) that retain the structural and trafficking properties of wt BoNTs. In this report we describe the properties of one such derivative, BoNT/A ad, which was rendered atoxic by introducing two amino acid mutations to the light chain (LC) of wt BoNT/A, and which is being developed as a molecular vehicle for delivering drugs to the neuronal cytoplasm. The neuronal binding, internalization, and intracellular trafficking of BoNT/A ad in primary hippocampal cultures was evaluated using three complimentary techniques: flow cytometry, immunohistochemistry, and Western blotting. Neuronal binding of BoNT ad was significantly increased when neurons were incubated in depolarizing medium. Flow cytometry demonstrated that BoNT/A ad internalized into neurons but not glia. After 24 hours, the majority of the neuron-bound BoNT/A ad became internalized, as determined by its resistance to pronase E-induced proteolytic degradation of proteins associated with the plasma membrane of intact cells. Significant amounts of the atoxic LC accumulated in a Triton X-100-extractable fraction of the neurons, and persisted as such for at least 11 days with no evidence of degradation. Immunocytochemical analysis demonstrated that the LC of BoNT/A ad was translocated to the neuronal cytoplasm after uptake and was specifically targeted to SNARE proteins. The atoxic LC consistently co-localized with synaptic markers SNAP-25 and VAMP-2, but was rarely co-localized with markers for early or late endosomes. These data demonstrate that BoNT/A ad mimics the trafficking properties of wt BoNT/A, confirming that our platform for designing and expressing BoNT derivatives provides an accessible system for elucidating the molecular details of BoNT trafficking, and can potentially be used to address multiple medical and biodefense needs.
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Affiliation(s)
- Edwin J. Vazquez-Cintron
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Maksim Vakulenko
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Philip A. Band
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
- Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, New York, New York, United States of America
| | - Larry H. Stanker
- USDA, Agriculture Research Service, Albany, California, United States of America
| | - Eric A. Johnson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Konstantin Ichtchenko
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
- * E-mail:
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Höltje M, Schulze S, Strotmeier J, Mahrhold S, Richter K, Binz T, Bigalke H, Ahnert-Hilger G, Rummel A. Exchanging the minimal cell binding fragments of tetanus neurotoxin in botulinum neurotoxin A and B impacts their toxicity at the neuromuscular junction and central neurons. Toxicon 2013; 75:108-21. [DOI: 10.1016/j.toxicon.2013.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 06/09/2013] [Accepted: 06/17/2013] [Indexed: 12/20/2022]
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Abstract
Botulism is a severe neuroparalytic disease caused by the toxins produced from several Clostridium species. Botulinum neurotoxins (BoNTs) cause flaccid paralysis by inducing a blockade at voluntary motor and autonomic cholinergic junctions that, if not treated, can be fatal. Vaccination to elicit protective circulating antibodies that bind, neutralize and clear toxins before they can be internalized and affect cholinergic neurons remains the most effective form of protection against BoNT. A pentavalent BoNT toxoid vaccine administered in the USA under an Investigational New Drug protocol to at-risk workers was discontinued by the CDC in 2011 due to diminished potency and reactogenic effects. Subsequent research efforts have primarily focused on recombinant protein antigens. This review focuses on the development of a recombinant bivalent vaccine (rBV A/B) composed of purified recombinant BoNT/A and BoNT/B receptor-binding domain proteins, as well as presenting a summary of progress and issues associated with alternative vaccines currently being developed against botulism.
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Affiliation(s)
- Robert P Webb
- US Army Medical Research Institute for Infectious Diseases, Frederick, MD 21702, USA
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42
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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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43
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Shoemaker CB, Oyler GA. Persistence of Botulinum neurotoxin inactivation of nerve function. Curr Top Microbiol Immunol 2013; 364:179-96. [PMID: 23239354 DOI: 10.1007/978-3-642-33570-9_9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The extraordinary persistence of intoxication occurring after exposure to some Botulinum neurotoxin (BoNT) serotypes is both a therapeutic marvel and a biodefense nightmare. Understanding the mechanisms underlying BoNT persistence will offer new strategies for improving the efficacy and extending the applications of BoNT therapeutic agents as well as for treating the symptoms of botulism. Research indicates that the persistence of BoNT intoxication can be influenced both by the ability of the toxin protease or its cleaved soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein substrate to resist turnover. Protease turnover seems to be mediated in part by the ubiquitin-proteasome system (UPS) and efforts to manipulate the UPS may prove to be an effective strategy for improving therapeutic utility of BoNT products and in the development of botulism antidotes.
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Affiliation(s)
- Charles B Shoemaker
- Division of Infectious Diseases, Department of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, MA 01536, USA.
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Molecular dissection of botulinum neurotoxin reveals interdomain chaperone function. Toxicon 2013; 75:101-7. [PMID: 23396042 DOI: 10.1016/j.toxicon.2013.01.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/10/2013] [Accepted: 01/17/2013] [Indexed: 11/23/2022]
Abstract
Clostridium botulinum neurotoxin (BoNT) is a multi-domain protein made up of the approximately 100 kDa heavy chain (HC) and the approximately 50 kDa light chain (LC). The HC can be further subdivided into two halves: the N-terminal translocation domain (TD) and the C-terminal Receptor Binding Domain (RBD). We have investigated the minimal requirements for channel activity and LC translocation. We utilize a cellular protection assay and a single channel/single molecule LC translocation assay to characterize in real time the channel and chaperone activities of BoNT/A truncation constructs in Neuro 2A cells. The unstructured, elongated belt region of the TD is demonstrated to be dispensable for channel activity, although may be required for productive LC translocation. We show that the RBD is not necessary for channel activity or LC translocation, however it dictates the pH threshold of channel insertion into the membrane. These findings indicate that each domain functions as a chaperone for the others in addition to their individual functions, working in concert to achieve productive intoxication.
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Pirazzini M, Rossetto O, Bertasio C, Bordin F, Shone CC, Binz T, Montecucco C. Time course and temperature dependence of the membrane translocation of tetanus and botulinum neurotoxins C and D in neurons. Biochem Biophys Res Commun 2012. [PMID: 23200837 DOI: 10.1016/j.bbrc.2012.11.048] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Tetanus and botulinum neurotoxins act inside nerve terminals and, therefore, they have to translocate across a membrane to reach their targets. This translocation is driven by a pH gradient, acidic on the cis side and neutral on the cytosol. Recently, a protocol to induce translocation from the plasma membrane was established. Here, we have used this approach to study the temperature dependence and time course of the entry of the L chain of tetanus neurotoxin and of botulinum neurotoxins type C and D across the plasma membrane of cerebellar granular neurons. The time course of translocation of the L chain varies for the three neurotoxins, but it remains in the range of minutes at 37 °C, whilst it takes much longer at 20 °C. BoNT/C does not enter neurons at 20 °C. Translocation also depends on the dimension of the pH gradient. These data are discussed with respect to the contribution of the membrane translocation step to the total time to paralysis and to the low toxicity of these neurotoxins in cold-blood vertebrates.
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Affiliation(s)
- Marco Pirazzini
- Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Viale G. Colombo 3, 35131 Padova, Italy
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The thioredoxin reductase-thioredoxin system is involved in the entry of tetanus and botulinum neurotoxins in the cytosol of nerve terminals. FEBS Lett 2012. [DOI: 10.1016/j.febslet.2012.11.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Edupuganti OP, Ovsepian SV, Wang J, Zurawski TH, Schmidt JJ, Smith L, Lawrence GW, Dolly JO. Targeted delivery into motor nerve terminals of inhibitors for SNARE-cleaving proteases via liposomes coupled to an atoxic botulinum neurotoxin. FEBS J 2012; 279:2555-67. [PMID: 22607388 DOI: 10.1111/j.1742-4658.2012.08638.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A targeted drug carrier (TDC) is described for transferring functional proteins or peptides into motor nerve terminals, a pivotal locus for therapeutics to treat neuromuscular disorders. It exploits the pronounced selectivity of botulinum neurotoxin type B (BoNT/B) for interacting with acceptors on these cholinergic nerve endings and becoming internalized. The gene encoding an innocuous BoNT/B protease-inactive mutant (BoTIM) was fused to that for core streptavidin, expressed in Escherichia coli and the purified protein was conjugated to surface-biotinylated liposomes. Such decorated liposomes, loaded with fluorescein as traceable cargo, acquired pronounced specificity for motor nerve terminals in isolated mouse hemidiaphragms and facilitated the intraneuronal transfer of the fluor, as revealed by confocal microscopy. Delivery of the protease light chain of botulinum neurotoxin type A (BoNT/A) via this TDC accelerated the onset of neuromuscular paralysis, indicative of improved translocation of this enzyme into the presynaptic cytosol with subsequent proteolytic inactivation of synaptosomal-associated protein of molecular mass 25 kDa (SNAP-25), an exocytotic soluble N-ethyl-maleimide-sensitive factor attachment protein receptor (SNARE) essential for neurotransmitter release. BoTIM-coupled liposomes, loaded with peptide inhibitors of proteases, yielded considerable attenuation of the neuroparalytic effects of BoNT/A or BoNT/F as a result of their cytosolic transfer, the first in situ demonstration of the ability of designer antiproteases to suppress the symptoms of botulism ex vivo. Delivery of the BoNT/A inhibitor by liposomes targeted with the full-length BoTIM proved more effective than that mediated by its C-terminal neuroacceptor-binding domain. This demonstrated versatility of TDC for nonviral cargo transfer into cholinergic nerve endings has unveiled its potential for direct delivery of functional targets into motor nerve endings.
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Affiliation(s)
- Om P Edupuganti
- International Centre for Neurotherapeutics, Dublin City University, Dublin, Ireland
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48
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Davletov B, Ferrari E, Ushkaryov Y. Presynaptic neurotoxins: an expanding array of natural and modified molecules. Cell Calcium 2012; 52:234-40. [PMID: 22658826 DOI: 10.1016/j.ceca.2012.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 05/04/2012] [Accepted: 05/13/2012] [Indexed: 11/15/2022]
Abstract
The process of neurotransmitter release from nerve terminals is a target for a wide array of presynaptic toxins produced by various species, from humble bacteria to arthropods to vertebrate animals. Unlike other toxins, most presynaptic neurotoxins do not kill cells but simply inhibit or activate synaptic transmission. In this review, we describe two types of presynaptic neurotoxins: clostridial toxins and latrotoxins, which are, respectively, the most potent blockers and stimulators of neurotransmitter release. These toxins have been instrumental in defining presynaptic functions and are now widely used in research and medicine. Here, we would like to analyse the diversity of these toxins and demonstrate how the knowledge of their structures and mechanisms of action can help us to design better tools for research and medical applications. We will look at natural and synthetic variations of these exquisite molecular machines, highlighting recent advances in our understanding of presynaptic toxins and questions that remain to be answered. If we can decipher how a given biomolecule is modified by nature to target different species, we will be able to design new variants that carry only desired characteristics to achieve specific therapeutic, agricultural or research goals. Indeed, a number of research groups have already initiated a quest to harness the power of natural toxins with the aim of making them more specifically targeted and safer for future research and medical applications.
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Affiliation(s)
- Bazbek Davletov
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
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49
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Shoemaker CB, Oyler GA. Persistence of Botulinum Neurotoxin Inactivation of Nerve Function. Curr Top Microbiol Immunol 2012. [DOI: 10.1007/978-3-662-45790-0_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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50
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Fischer A. Synchronized Chaperone Function of Botulinum Neurotoxin Domains Mediates Light Chain Translocation into Neurons. Curr Top Microbiol Immunol 2012. [DOI: 10.1007/978-3-662-45790-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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