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An JM, Shahriar SMS, Lee DY, Hwang SR, Lee YK. Pore Size-Dependent Stereoscopic Hydrogels Enhance the Therapeutic Efficiency of Botulinum Toxin for the Treatment of Nerve-Related Diseases. ACS APPLIED MATERIALS & INTERFACES 2022; 14:19139-19153. [PMID: 35452222 DOI: 10.1021/acsami.2c01738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Botulinum toxin (BoNT) is a major neurotherapeutic protein that has been used at low doses for diverse pharmacological applications. However, the pleiotropic effect of BoNT depends on multiple periodic injections owing to its rapid elimination profile, short-term therapeutic effect, and high mortality rate when administered at high doses. In addition to low patient compliance, these drawbacks represent the significant challenges that limit the further clinical use of BoNT. This study developed a new hydrogel-based single dosage form of BoNT by employing a one-step cross-linking chemistry. Its controlled porous structures and composition facilitated uniform drug distribution inside the hydrogel and controllable release of BoNT mediated by slow diffusion. A single dose remained stable for at least 2.5 months and showed sustained effect for at least 20 weeks, meeting the requirements for a single-dose form of BoNT. Additionally, this dosage form was evaluated as safe from all aspects of toxicology. This delivery system resulted in a 100% survival rate after administering a BoNT dose of 30 units, while a dose of more than 5 units of naked BoNT caused a 100% mortality rate within a few days. Overall, this strategy could provide patients with the first single-dose treatment option of BoNT and improve their quality of life.
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Affiliation(s)
- Jeong Man An
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul 04763, Republic of Korea
- Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 27469, Republic of Korea
- KB Biomed Inc., Chungju 27469, Republic of Korea
| | - S M Shatil Shahriar
- Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 27469, Republic of Korea
- KB Biomed Inc., Chungju 27469, Republic of Korea
- Department of Surgery-Transplant and Mary & Dick Holland Regenerative Medicine Program, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198-5940, United States
| | - Dong Yun Lee
- Department of Bioengineering, College of Engineering, and BK FOUR Biopharmaceutical Innovation Leader for Education and Research Group, Hanyang University, Seoul 04763, Republic of Korea
- Institute of Nano Science and Technology (INST), Hanyang University, Seoul 04763, Republic of Korea
| | - Seung Rim Hwang
- College of Pharmacy, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Yong-Kyu Lee
- Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 27469, Republic of Korea
- KB Biomed Inc., Chungju 27469, Republic of Korea
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2
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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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3
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Haywood EE, Handy NB, Lopez JW, Ho M, Wilson BA. Insertion-trigger residues differentially modulate endosomal escape by cytotoxic necrotizing factor toxins. J Biol Chem 2021; 297:101347. [PMID: 34715130 PMCID: PMC8592880 DOI: 10.1016/j.jbc.2021.101347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/13/2021] [Accepted: 10/18/2021] [Indexed: 01/20/2023] Open
Abstract
The cellular specificity, potency, and modular nature of bacterial protein toxins enable their application for targeted cytosolic delivery of therapeutic cargo. Efficient endosomal escape is a critical step in the design of bacterial toxin-inspired drug delivery (BTIDD) vehicles to avoid lysosomal degradation and promote optimal cargo delivery. The cytotoxic necrotizing factor (CNF) family of modular toxins represents a useful model for investigating cargo-delivery mechanisms due to the availability of many homologs with high sequence identity, their flexibility in swapping domains, and their differential activity profiles. Previously, we found that CNFy is more sensitive to endosomal acidification inhibitors than CNF1 and CNF2. Here, we report that CNF3 is even less sensitive than CNF1/2. We identified two amino acid residues within the putative translocation domain (E374 and E412 in CNFy, Q373 and S411 in CNF3) that differentiate between these two toxins. Swapping these corresponding residues in each toxin changed the sensitivity to endosomal acidification and efficiency of cargo-delivery to be more similar to the other toxin. Results suggested that trafficking to the more acidic late endosome is required for cargo delivery by CNFy but not CNF3. This model was supported by results from toxin treatment of cells in the presence of NH4Cl, which blocks endosomal acidification, and of small-molecule inhibitors EGA, which blocks trafficking to late endosomes, and ABMA, which blocks endosomal escape and trafficking to the lysosomal degradative pathway. These findings suggest that it is possible to fine-tune endosomal escape and cytosolic cargo delivery efficiency in designing BTIDD platforms.
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Affiliation(s)
- Elizabeth E Haywood
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Nicholas B Handy
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - James W Lopez
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Mengfei Ho
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Brenda A Wilson
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
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4
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Roesl C, Evans ER, Dissanayake KN, Boczonadi V, Jones RA, Jordan GR, Ledahawsky L, Allen GCC, Scott M, Thomson A, Wishart TM, Hughes DI, Mead RJ, Shone CC, Slater CR, Gillingwater TH, Skehel PA, Ribchester RR. Confocal Endomicroscopy of Neuromuscular Junctions Stained with Physiologically Inert Protein Fragments of Tetanus Toxin. Biomolecules 2021; 11:1499. [PMID: 34680132 PMCID: PMC8534034 DOI: 10.3390/biom11101499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 01/09/2023] Open
Abstract
Live imaging of neuromuscular junctions (NMJs) in situ has been constrained by the suitability of ligands for inert vital staining of motor nerve terminals. Here, we constructed several truncated derivatives of the tetanus toxin C-fragment (TetC) fused with Emerald Fluorescent Protein (emGFP). Four constructs, namely full length emGFP-TetC (emGFP-865:TetC) or truncations comprising amino acids 1066-1315 (emGFP-1066:TetC), 1093-1315 (emGFP-1093:TetC) and 1109-1315 (emGFP-1109:TetC), produced selective, high-contrast staining of motor nerve terminals in rodent or human muscle explants. Isometric tension and intracellular recordings of endplate potentials from mouse muscles indicated that neither full-length nor truncated emGFP-TetC constructs significantly impaired NMJ function or transmission. Motor nerve terminals stained with emGFP-TetC constructs were readily visualised in situ or in isolated preparations using fibre-optic confocal endomicroscopy (CEM). emGFP-TetC derivatives and CEM also visualised regenerated NMJs. Dual-waveband CEM imaging of preparations co-stained with fluorescent emGFP-TetC constructs and Alexa647-α-bungarotoxin resolved innervated from denervated NMJs in axotomized WldS mouse muscle and degenerating NMJs in transgenic SOD1G93A mouse muscle. Our findings highlight the region of the TetC fragment required for selective binding and visualisation of motor nerve terminals and show that fluorescent derivatives of TetC are suitable for in situ morphological and physiological characterisation of healthy, injured and diseased NMJs.
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Affiliation(s)
- Cornelia Roesl
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Elizabeth R. Evans
- Public Health England, National Infection Service, Porton Down, Salisbury SP4 0JG, UK; (E.R.E.); (C.C.S.)
| | - Kosala N. Dissanayake
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Veronika Boczonadi
- Applied Neuromuscular Junction Facility, Bio-Imaging Unit, Biosciences Institute, University of Newcastle-upon-Tyne, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK; (V.B.); (C.R.S.)
| | - Ross A. Jones
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Graeme R. Jordan
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Leire Ledahawsky
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Guy C. C. Allen
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Molly Scott
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Alanna Thomson
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Thomas M. Wishart
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, College of Medicine and Veterinary Medicine, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK;
| | - David I. Hughes
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK;
| | - Richard J. Mead
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Glossop Road, Sheffield S10 2HQ, UK;
| | - Clifford C. Shone
- Public Health England, National Infection Service, Porton Down, Salisbury SP4 0JG, UK; (E.R.E.); (C.C.S.)
| | - Clarke R. Slater
- Applied Neuromuscular Junction Facility, Bio-Imaging Unit, Biosciences Institute, University of Newcastle-upon-Tyne, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK; (V.B.); (C.R.S.)
| | - Thomas H. Gillingwater
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Paul A. Skehel
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Richard R. Ribchester
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
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5
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McNutt PM, Vazquez-Cintron EJ, Tenezaca L, Ondeck CA, Kelly KE, Mangkhalakhili M, Machamer JB, Angeles CA, Glotfelty EJ, Cika J, Benjumea CH, Whitfield JT, Band PA, Shoemaker CB, Ichtchenko K. Neuronal delivery of antibodies has therapeutic effects in animal models of botulism. Sci Transl Med 2021; 13:eabd7789. [PMID: 33408188 PMCID: PMC8176400 DOI: 10.1126/scitranslmed.abd7789] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/20/2020] [Indexed: 11/02/2022]
Abstract
Botulism is caused by a potent neurotoxin that blocks neuromuscular transmission, resulting in death by asphyxiation. Currently, the therapeutic options are limited and there is no antidote. Here, we harness the structural and trafficking properties of an atoxic derivative of botulinum neurotoxin (BoNT) to transport a function-blocking single-domain antibody into the neuronal cytosol where it can inhibit BoNT serotype A (BoNT/A1) molecular toxicity. Post-symptomatic treatment relieved toxic signs of botulism and rescued mice, guinea pigs, and nonhuman primates after lethal BoNT/A1 challenge. These data demonstrate that atoxic BoNT derivatives can be harnessed to deliver therapeutic protein moieties to the neuronal cytoplasm where they bind and neutralize intracellular targets in experimental models. The generalizability of this platform might enable delivery of antibodies and other protein-based therapeutics to previously inaccessible intraneuronal targets.
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Affiliation(s)
- Patrick M McNutt
- Wake Forest School of Medicine, Wake Forest Institute for Regenerative Medicine, Winston-Salem, NC 27101, USA
- United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Edwin J Vazquez-Cintron
- United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
- CytoDel Inc., New York, NY 10016, USA
- City College of City University of New York, NY 10031, USA
| | - Luis Tenezaca
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
- CytoDel Inc., New York, NY 10016, USA
| | - Celinia A Ondeck
- United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Kyle E Kelly
- United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Mark Mangkhalakhili
- United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - James B Machamer
- 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 Grossman School of Medicine, New York, NY 10016, USA
| | - Elliot J Glotfelty
- United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Jaclyn Cika
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Cesar H Benjumea
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | | | - Philip A Band
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
- CytoDel Inc., New York, NY 10016, USA
- Department of Orthopaedic Surgery, New York University Langone Orthopedic Hospital, New York, NY 10016, USA
| | - Charles B Shoemaker
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA 01536, USA
| | - Konstantin Ichtchenko
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA.
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6
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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:eaaz4197. [PMID: 33408184 DOI: 10.1126/scitranslmed.aaz4197] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [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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7
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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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8
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Vazquez-Cintron E, Tenezaca L, Angeles C, Syngkon A, Liublinska V, Ichtchenko K, Band P. Pre-Clinical Study of a Novel Recombinant Botulinum Neurotoxin Derivative Engineered for Improved Safety. Sci Rep 2016; 6:30429. [PMID: 27484492 PMCID: PMC4971498 DOI: 10.1038/srep30429] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 07/01/2016] [Indexed: 11/09/2022] Open
Abstract
Cyto-012 is a recombinant derivative of Botulinum neurotoxin Type A (BoNT/A). It primarily differs from wild type (wt) BoNT/A1 in that it incorporates two amino acid substitutions in the catalytic domain of the light chain (LC) metalloprotease (E224 > A and Y366 > A), designed to provide a safer clinical profile. Cyto-012 is specifically internalized into rat cortical and hippocampal neurons, and cleaves Synaptosomal-Associated Protein 25 (SNAP-25), the substrate of wt BoNT/A, but exhibits slower cleavage kinetics and therefore requires a higher absolute dose to exhibit pharmacologic activity. The pharmacodynamics of Cyto-012 and wt BoNT/A have similar onset and duration of action using the Digital Abduction Assay (DAS). Intramuscular LD50 values for Cyto-012 and wt BoNT/A respectively, were 0.63 ug (95% CI = 0.61, 0.66) and 6.22 pg (95% CI = 5.42, 7.02). ED50 values for Cyto-012 and wt BoNT/A were respectively, 0.030 ug (95% CI = 0.026, 0.034) and 0.592 pg (95% CI = 0.488, 0.696). The safety margin (intramuscular LD50/ED50 ratio) for Cyto-012 was found to be improved 2-fold relative to wt BoNT/A (p < 0.001). The DAS response to Cyto-012 was diminished when a second injection was administered 32 days after the first. These data suggest that the safety margin of BoNT/A can be improved by modulating their activity towards SNAP-25.
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Affiliation(s)
- Edwin Vazquez-Cintron
- CytoDel LLC, New York, 10027, United States
- New York University School of Medicine, Department of Pharmacology and Molecular Biochemistry, New York, 10016, United States
- City College of New York, Department of Biology, New York, 10023, United States
| | - Luis Tenezaca
- CytoDel LLC, New York, 10027, United States
- New York University School of Medicine, Department of Pharmacology and Molecular Biochemistry, New York, 10016, United States
| | - Christopher Angeles
- New York University School of Medicine, Department of Pharmacology and Molecular Biochemistry, New York, 10016, United States
| | - Aurelia Syngkon
- New York University School of Medicine, Department of Pharmacology and Molecular Biochemistry, New York, 10016, United States
| | - Victoria Liublinska
- Harvard University, Office of Institutional Research, Cambridge, 02138, United States
| | - Konstantin Ichtchenko
- New York University School of Medicine, Department of Pharmacology and Molecular Biochemistry, New York, 10016, United States
| | - Philip Band
- CytoDel LLC, New York, 10027, United States
- New York University School of Medicine, Department of Pharmacology and Molecular Biochemistry, New York, 10016, United States
- Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, New York, 10003, United States
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Retargeting the Clostridium botulinum C2 toxin to the neuronal cytosol. Sci Rep 2016; 6:23707. [PMID: 27025362 PMCID: PMC4812341 DOI: 10.1038/srep23707] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 03/10/2016] [Indexed: 12/16/2022] Open
Abstract
Many biological toxins are known to attack specific cell types, delivering their enzymatic payloads to the cytosol. This process can be manipulated by molecular engineering of chimeric toxins. Using toxins with naturally unlinked components as a starting point is advantageous because it allows for the development of payloads separately from the binding/translocation components. Here the Clostridium botulinum C2 binding/translocation domain was retargeted to neural cell populations by deleting its non-specific binding domain and replacing it with a C. botulinum neurotoxin binding domain. This fusion protein was used to deliver fluorescently labeled payloads to Neuro-2a cells. Intracellular delivery was quantified by flow cytometry and found to be dependent on artificial enrichment of cells with the polysialoganglioside receptor GT1b. Visualization by confocal microscopy showed a dissociation of payloads from the early endosome indicating translocation of the chimeric toxin. The natural Clostridium botulinum C2 toxin was then delivered to human glioblastoma A172 and synchronized HeLa cells. In the presence of the fusion protein, native cytosolic enzymatic activity of the enzyme was observed and found to be GT1b-dependent. This retargeted toxin may enable delivery of therapeutics to peripheral neurons and be of use in addressing experimental questions about neural physiology.
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Monoclonal Antibodies Targeting the Alpha-Exosite of Botulinum Neurotoxin Serotype/A Inhibit Catalytic Activity. PLoS One 2015; 10:e0135306. [PMID: 26275214 PMCID: PMC4537209 DOI: 10.1371/journal.pone.0135306] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 07/20/2015] [Indexed: 12/12/2022] Open
Abstract
The paralytic disease botulism is caused by botulinum neurotoxins (BoNT), multi-domain proteins containing a zinc endopeptidase that cleaves the cognate SNARE protein, thereby blocking acetylcholine neurotransmitter release. Antitoxins currently used to treat botulism neutralize circulating BoNT but cannot enter, bind to or neutralize BoNT that has already entered the neuron. The light chain endopeptidase domain (LC) of BoNT serotype A (BoNT/A) was targeted for generation of monoclonal antibodies (mAbs) that could reverse paralysis resulting from intoxication by BoNT/A. Single-chain variable fragment (scFv) libraries from immunized humans and mice were displayed on the surface of yeast, and 19 BoNT/A LC-specific mAbs were isolated by using fluorescence-activated cell sorting (FACS). Affinities of the mAbs for BoNT/A LC ranged from a KD value of 9.0×10−11 M to 3.53×10−8 M (mean KD 5.38×10−9 M and median KD 1.53×10−9 M), as determined by flow cytometry analysis. Eleven mAbs inhibited BoNT/A LC catalytic activity with IC50 values ranging from 8.3 ~73×10−9 M. The fine epitopes of selected mAbs were also mapped by alanine-scanning mutagenesis, revealing that the inhibitory mAbs bound the α-exosite region remote from the BoNT/A LC catalytic center. The results provide mAbs that could prove useful for intracellular reversal of paralysis post-intoxication and further define epitopes that could be targeted by small molecule inhibitors.
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Brown R, Dissanayake KN, Skehel PA, Ribchester RR. Endomicroscopy and electromyography of neuromuscular junctions in situ. Ann Clin Transl Neurol 2014; 1:867-83. [PMID: 25540801 PMCID: PMC4265058 DOI: 10.1002/acn3.124] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 12/12/2022] Open
Abstract
Objective Electromyography (EMG) is used routinely to diagnose neuromuscular dysfunction in a wide range of peripheral neuropathies, myopathies, and neuromuscular degenerative diseases including motor neuron diseases such as amyotrophic lateral sclerosis (ALS). Definitive neurological diagnosis may also be indicated by the analysis of pathological neuromuscular innervation in motor-point biopsies. Our objective in this study was to preempt motor-point biopsy by combining live imaging with electrophysiological analysis of slow degeneration of neuromuscular junctions (NMJs) in vivo. Methods We combined conventional needle electromyography with fiber-optic confocal endomicroscopy (CEM), using an integrated hand-held, 1.5-mm-diameter probe. We utilized as a test bed, various axotomized muscles in the hind limbs of anaesthetized, double-homozygous thy1.2YFP16: WldS mice, which coexpress the Wallerian-degeneration Slow (WldS) protein and yellow fluorescent protein (YFP) in motor neurons. We also tested exogenous vital stains, including Alexa488-α-bungarotoxin; the styryl pyridinium dye 4-Di-2-Asp; and a GFP conjugate of botulinum toxin Type A heavy chain (GFP-HcBoNT/A). Results We show that an integrated EMG/CEM probe is effective in longitudinal evaluation of functional and morphological changes that take place over a 7-day period during axotomy-induced, slow neuromuscular synaptic degeneration. EMG amplitude declined in parallel with overt degeneration of motor nerve terminals. EMG/CEM was safe and effective when nerve terminals and motor endplates were selectively stained with vital dyes. Interpretation Our findings constitute proof-of-concept, based on live imaging in an animal model, that combining EMG/CEM may be useful as a minimally invasive precursor or alternative to motor-point biopsy in neurological diagnosis and for monitoring local administration of potential therapeutics.
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Affiliation(s)
- Rosalind Brown
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Kosala N Dissanayake
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Paul A Skehel
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Richard R Ribchester
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
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Baskaran P, Thyagarajan B. Acute and chronic effects of botulinum neurotoxin a on the mammalian neuromuscular junction. Muscle Nerve 2014; 50:206-15. [PMID: 24218344 DOI: 10.1002/mus.24119] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 10/30/2013] [Accepted: 11/07/2013] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Botulinum neurotoxin A (BoNT/A) cleaves SNAP-25 and inhibits acetylcholine (ACh) release at the neuromuscular junctions (NMJ) to cause neuroparalysis. Previous reports indicate a dyssynchrony between the inhibitory effect of BoNT/A on ACh release and SNAP-25 cleavage. METHODS We tested the in vitro (acute; 90 min) and in vivo (chronic; 12 h) effects of BoNT/A on stimulus-evoked ACh release (SEAR), twitch tension, and SNAP-25 cleavage in isolated extensor digitorum longus (EDL) nerve-muscle preparations (NMP). RESULTS In vitro or in vivo BoNT/A poisoning inhibited SEAR and twitch tension. Conversely, SNAP-25 cleavage and inhibition of spontaneous release frequency were observed only in NMP poisoned with BoNT/A in vivo. Moreover, chronic treatment of BoNT/A inhibited ionomycin stimulated Ca(2+) signals in Neuro 2a cells. CONCLUSIONS These results demonstrate that the inhibition of SEAR precedes SNAP-25 cleavage and suggest involvement of a more complex mechanism for the inhibitory effect of BoNT/A at the NMJ.
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Affiliation(s)
- Padmamalini Baskaran
- School of Pharmacy, 1000 East University Avenue, University of Wyoming, Laramie, Wyoming, 82071
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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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Repella TL, Ho M, Wilson BA. Determinants of pH-dependent modulation of translocation in dermonecrotic G-protein-deamidating toxins. Toxins (Basel) 2013; 5:1167-79. [PMID: 23888517 PMCID: PMC3717775 DOI: 10.3390/toxins5061167] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cytotoxic necrotizing factors from E. coli (CNF1, CNF2) and Yersinia (CNFy) share N-terminal sequence similarity with Pasteurella multocida toxin (PMT). This common N-terminal region harbors the receptor-binding and translocation domains that mediate uptake and delivery of the C-terminal catalytic cargo domains into the host cytosol. Subtle variations in the N-terminal ~500 amino acids of CNFs and PMT could allow for selective recognition of cellular receptors and thus, selective target cell specificity. Through studies with cellular inhibitors, we have identified an additional novel function for this region in modulating responses of these toxin proteins to changes in pH during intoxication and delivery of the catalytic cargo domain into the cytosol.
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Affiliation(s)
- Tana L Repella
- Department of Microbiology, School of Molecular and Cell Biology, University of Illinois atUrbana-Champaign, Urbana, IL 61801, USA.
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15
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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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Ho M, Goh CH, Brothers MC, Wang S, Young RL, Ou Y, Lui JNM, Kalafatis M, Lan X, Wolf AE, Rienstra CM, Wilson BA. Glycine insertion at protease cleavage site of SNAP25 resists cleavage but enhances affinity for botulinum neurotoxin serotype A. Protein Sci 2012; 21:318-26. [PMID: 22170566 DOI: 10.1002/pro.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The light chain of botulinum neurotoxin A (BoNT/A-LC) is a Zn-dependent protease that specifically cleaves SNAP25 of the SNARE complex, thereby impairing vesicle fusion and neurotransmitter release at neuromuscular junctions. The C-terminus of SNAP25 (residues 141-206) retains full activity for BoNT/A-LC-catalyzed cleavage at P1-P1' (Gln197-Arg198). Using the structure of a complex between the C-terminus of SNAP25 and BoNT/A-LC as a model to design SNAP25-derived pseudosubstrate inhibitors (SNAPIs) that prevent presentation of the scissile bond to the active site, we introduced multiple His residues to replace Ala-Asn-Gln-Arg (residues 195-198) at the substrate cleavage site, with the intent to identify possible side-chain interactions with the active site Zn. We also introduced multiple Gly residues between the P1-P1' residues to explore the spatial tolerance within the active-site cleft. Using a FRET substrate YsCsY, we compared a series of SNAPIs for inhibition of BoNT/A-LC. Among the SNAPIs tested, several known cleavage-resistant, single-point mutants of SNAP25 were poor inhibitors, with most of the mutants losing binding affinity. Replacement with His at the active site did not improve inhibition over wildtype substrate. In contrast, Gly-insertion mutants were not only resistant to cleavage, but also surprisingly showed enhanced affinity for BoNT/A-LC. Two of the Gly-insertion mutants exhibited 10-fold lower IC₅₀ values than the wildtype 66-mer SNAP25 peptide. Our findings illustrate a scenario, where the induced fit between enzyme and bound pseudosubstrate fails to produce the strain and distortion required for catalysis to proceed.
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Affiliation(s)
- Mengfei Ho
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Retargeting Clostridium difficile Toxin B to Neuronal Cells as a Potential Vehicle for Cytosolic Delivery of Therapeutic Biomolecules to Treat Botulism. J Toxicol 2011; 2012:760142. [PMID: 21941543 PMCID: PMC3177232 DOI: 10.1155/2012/760142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 07/13/2011] [Indexed: 12/30/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) deliver a protease to neurons which can cause a flaccid paralysis called botulism. Development of botulism antidotes will require neuronal delivery of agents that inhibit or destroy the BoNT protease. Here, we investigated the potential of engineering Clostridium difficile toxin B (TcdB) as a neuronal delivery vehicle by testing two recombinant TcdB chimeras. For AGT-TcdB chimera, an alkyltransferase (AGT) was appended to the N-terminal glucosyltransferase (GT) of TcdB. Recombinant AGT-TcdB had alkyltransferase activity, and the chimera was nearly as toxic to Vero cells as wild-type TcdB, suggesting efficient cytosolic delivery of the AGT/GT fusion. For AGT-TcdB-BoNT/A-Hc, the receptor-binding domain (RBD) of TcdB was replaced by the equivalent RBD from BoNT/A (BoNT/A-Hc). AGT-TcdB-BoNT/A-Hc was >25-fold more toxic to neuronal cells and >25-fold less toxic to Vero cells than AGT-TcdB. Thus, TcdB can be engineered for cytosolic delivery of biomolecules and improved targeting of neuronal cells.
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Kuo CL, Oyler GA, Shoemaker CB. Accelerated neuronal cell recovery from Botulinum neurotoxin intoxication by targeted ubiquitination. PLoS One 2011; 6:e20352. [PMID: 21629663 PMCID: PMC3101245 DOI: 10.1371/journal.pone.0020352] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 04/19/2011] [Indexed: 11/19/2022] Open
Abstract
Botulinum neurotoxin (BoNT), a Category A biodefense agent, delivers a protease to motor neuron cytosol that cleaves one or more soluble NSF attachment protein receptors (SNARE) proteins involved in neurotransmission to cause a flaccid paralysis. No antidotes exist to reverse symptoms of BoNT intoxication so severely affected patients require artificial respiration with prolonged intensive care. Time to recovery depends on toxin serotype because the intraneuronal persistence of the seven known BoNT serotypes varies widely from days to many months. Our therapeutic antidote strategy is to develop ‘targeted F-box’ (TFB) agents that target the different intraneuronal BoNT proteases for accelerated degradation by the ubiquitin proteasome system (UPS), thus promoting rapid recovery from all serotypes. These agents consist of a camelid heavy chain-only VH (VHH) domain specific for a BoNT protease fused to an F-box domain recognized by an intraneuronal E3-ligase. A fusion protein containing the 14 kDa anti-BoNT/A protease VHH, ALcB8, joined to a 15 kDa F-box domain region of TrCP (D5) was sufficient to cause increased ubiquitination and accelerate turnover of the targeted BoNT/A protease within neurons. Neuronal cells expressing this TFB, called D5-B8, were also substantially resistant to BoNT/A intoxication and recovered from intoxication at least 2.5 fold quicker than control neurons. Fusion of D5 to a VHH specific for BoNT/B protease (BLcB10) led to accelerated turnover of the targeted protease within neurons, thus demonstrating the modular nature of these therapeutic agents and suggesting that development of similar therapeutic agents specific to all botulinum serotypes should be readily achievable.
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Affiliation(s)
- Chueh-Ling Kuo
- Department of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, Massachusetts, United States of America
| | - George A. Oyler
- Synaptic Research LLC, Baltimore, Maryland, United States of America
| | - Charles B. Shoemaker
- Department of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, Massachusetts, United States of America
- * E-mail:
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