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Punga AR, Alimohammadi M, Liik M. Keeping up appearances: Don't frown upon the effects of botulinum toxin injections in facial muscles. Clin Neurophysiol Pract 2023; 8:169-173. [PMID: 37681120 PMCID: PMC10480586 DOI: 10.1016/j.cnp.2023.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 05/04/2023] [Accepted: 05/18/2023] [Indexed: 09/09/2023] Open
Abstract
Aesthetic use of low doses of Botulinum toxin (BoNT) injections into the facial muscles has become a leading non-surgical aesthetic treatment worldwide to reduce facial wrinkles, including glabellar lines, forehead lines, and periorbital wrinkles. Within these aesthetic applications, BoNT injections intend to reduce and prevent wrinkles, and the recommended usage of 2 years is often exceeded, which may result in atrophy of the injected muscles. The long-term effects of BoNT injections in the facial muscles and the evidence of diffusion of BoNT to surrounding muscles are obvious pitfalls and challenges for clinical neurophysiologists in differential diagnosing neuromuscular transmission failures. Also, this is further complicated by the risk of developing side effects upon permanent chemical denervation of facial muscles, with less possibility for reinnervation. This review summarizes the known long-term effects of BoNT over time in different facial muscles and the use of objective electrophysiological measures to evaluate these. A better understanding of the long-term effects of BoNT is essential to avoid misdiagnosing other neuromuscular disorders.
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Affiliation(s)
- Anna Rostedt Punga
- Department of Medical Sciences, Clinical Neurophysiology, Uppsala University and Uppsala University Hospital, Uppsala, Sweden
| | - Mohammad Alimohammadi
- Department of Medical Sciences, Dermatology and Venerology, Uppsala University and Uppsala University Hospital, Uppsala, Sweden
| | - Maarika Liik
- Department of Medical Sciences, Clinical Neurophysiology, Uppsala University and Uppsala University Hospital, Uppsala, Sweden
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2
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Patel EN, Lin L, Sneller MM, Eubanks LM, Tepp WH, Pellett S, Janda KD. Investigation of Salicylanilides as Botulinum Toxin Antagonists. ACS Infect Dis 2022; 8:1637-1645. [PMID: 35877209 PMCID: PMC9592073 DOI: 10.1021/acsinfecdis.2c00230] [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] [Indexed: 11/28/2022]
Abstract
Botulinum neurotoxin serotype A (BoNT/A) is recognized by the Centers for Disease Control and Prevention (CDC) as the most potent toxin and as a Tier 1 biowarfare agent. The severity and longevity of botulism stemming from BoNT/A is of significant therapeutic concern, and early administration of antitoxin-antibody therapy is the only approved pharmaceutical treatment for botulism. Small molecule therapeutic strategies have targeted both the heavy chain (HC) and the light chain (LC) catalytic active site and α-/β-exosites. The LC translocation mechanism has also been studied, but an effective, nontoxic inhibitor remains underexplored. In this work, we screened a library of salicylanilides as potential translocation inhibitors. Potential leads following a primary screen were further scrutinized to identify sal30, which has a cellular minimal concentration of a drug that is required for 50% inhibition (IC50) value of 141 nM. The inquiry of salicylanilide sal30's mechanism of action was explored through a self-quenched fluorogenic substrate conjugated to bovine serum albumin (DQ-BSA) fluorescence, confocal microscopy, and vacuolar H+-ATPase (V-ATPase) inhibition assays. The summation of these findings imply that endolysosomal proton translocation through the protonophore mechanism of sal30 causes endosome pH to increase, which in turn prevents LC translocation into cytosol, a process that requires an acidic pH. Thus, the inhibition of BoNT/A activity by salicylanilides likely occurs through disruption of pH-dependent endosomal LC translocation. We further probed BoNT inhibition by sal30 using additivity analysis studies with bafilomycin A1, a known BoNT/A LC translocation inhibitor, which indicated the absence of synergy between the two ionophores.
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Affiliation(s)
- Ealin N. Patel
- Department of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, California, 92037, United States
| | - Lucy Lin
- Department of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, California, 92037, United States
| | - Molly M. Sneller
- Department of Bacteriology, University of Wisconsin, 1550 Linden Drive, Madison, Wisconsin, 53706, United States
| | - Lisa M. Eubanks
- Department of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, California, 92037, United States
| | - William H. Tepp
- Department of Bacteriology, University of Wisconsin, 1550 Linden Drive, Madison, Wisconsin, 53706, United States
| | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin, 1550 Linden Drive, Madison, Wisconsin, 53706, United States
| | - Kim D. Janda
- Department of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, California, 92037, United States
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3
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A Review of Complications Due to the Use of Botulinum Toxin A for Cosmetic Indications. Aesthetic Plast Surg 2021; 45:1210-1220. [PMID: 33051718 DOI: 10.1007/s00266-020-01983-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 09/05/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Botulinum toxin A (botulinum toxin A) was found to provide a wide variety of therapeutic and aesthetic benefits as one of the most potent toxins in the world. Injectable remedies, including soft tissue fillers and botulinum toxin, have become very common in wrinkling and face rejuvenation management. While these methods of treatment are relatively safe, serious side effects can occur. In this review, the complications of BoNTA are highlighted. METHODS A literature research considered published journal articles (clinical trials or scientific reviews). Electronic databases (PubMed, Scopus, Science Direct) were searched using key terms, and for identification of additional relevant studies, reference lists have also been examined. Only articles published in English were included in this review with a time restriction from 2000 to 2020. RESULTS There are various injection-related adverse effects associated (AE) with botulinum toxins such as erythema, oedema, pain, ptosis of eyelid or brow and ecchymosis. The overall majority of adverse events identified are mild and temporary. CONCLUSION As the use of toxins becomes increasingly more common, adverse events can be expected to increase as well. The practitioners need to be aware of such AEs, and the patients should be informed of these before undertaking such procedures. LEVEL OF EVIDENCE III This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
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Lin L, Olson ME, Sugane T, Turner LD, Tararina MA, Nielsen AL, Kurbanov EK, Pellett S, Johnson EA, Cohen SM, Allen KN, Janda KD. Catch and Anchor Approach To Combat Both Toxicity and Longevity of Botulinum Toxin A. J Med Chem 2020; 63:11100-11120. [PMID: 32886509 PMCID: PMC7581224 DOI: 10.1021/acs.jmedchem.0c01006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Botulinum neurotoxins have remarkable persistence (∼weeks to months in cells), outlasting the small-molecule inhibitors designed to target them. To address this disconnect, inhibitors bearing two pharmacophores-a zinc binding group and a Cys-reactive warhead-were designed to leverage both affinity and reactivity. A series of first-generation bifunctional inhibitors was achieved through structure-based inhibitor design. Through X-ray crystallography, engagement of both the catalytic Zn2+ and Cys165 was confirmed. A second-generation series improved on affinity by incorporating known reversible inhibitor pharmacophores; the mechanism was confirmed by exhaustive dialysis, mass spectrometry, and in vitro evaluation against the C165S mutant. Finally, a third-generation inhibitor was shown to have good cellular activity and low toxicity. In addition to our findings, an alternative method of modeling time-dependent inhibition that simplifies assay setup and allows comparison of inhibition models is discussed.
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Affiliation(s)
- Lucy Lin
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Margaret E. Olson
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Takashi Sugane
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Lewis D. Turner
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Margarita A. Tararina
- Program in Biomolecular Pharmacology, Boston University School of Medicine, Boston, Massachusetts 02118, United States
| | - Alexander L. Nielsen
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Elbek K. Kurbanov
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Eric A. Johnson
- Department of Bacteriology, University of Wisconsin, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Seth M. Cohen
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Karen N. Allen
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Kim D. Janda
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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Aminianfar M, Parvardeh S, Soleimani M. In vitro and in vivo Assessment of Silver Nanoparticles Against Clostridium botulinum Type A Botulinum. Curr Drug Discov Technol 2020; 16:113-119. [PMID: 29623844 DOI: 10.2174/1570163815666180403163946] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 03/28/2018] [Accepted: 03/30/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Clostridium botulinum causes botulism, a serious paralytic illness that results from the ingestion of a botulinum toxin. Because silver nanoparticle products exhibit strong antimicrobial activity, applications for silver nanoparticles in healthcare have expanded. Therefore, the objective of the current study was to assess a therapeutic strategy for the treatment of botulism toxicity using silver nanoparticles. METHODS A preliminary test was conducted using doses that produce illness in laboratory animals to determine the absolute lethal dose (LD100) of botulinum toxin type A (BoNT/A) in mice. Next, the test animals were divided into six groups containing six mice each. Groups I, II and III were the negative control (botulinum toxin only), positive control-1 (nano-silver only) and positive control-2 (no treatment), respectively. The remaining groups were allocated to the toxin that was supplemented with three nano-silver treatments. RESULTS The mortality rates of mice caused by BoNT/A significantly reduced in the treatment groups with different doses and injection intervals of nano-silver when compared to the negative control group. BoNT/A toxicity induced by intraperitoneal injection of the toxin of Clostridium botulinum causes rapid death while when coupled with nano-osilver results in delayed death in mice. CONCLUSION These results, while open to future improvement, represent a preliminary step towards the satisfactory control of BoNT/A with the use of silver nanoparticles for human protection against this bioterrorism threat. Further study in this area can elucidate the underlying mechanism for detoxifying BoNT/A by silver nanoparticles.
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Affiliation(s)
- Mohammad Aminianfar
- Department of Infectious Diseases, School of Medicine, AJA University of Medical Sciences, Tehran, Iran
| | - Siavash Parvardeh
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohsen Soleimani
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Hobbs RJ, Thomas CA, Halliwell J, Gwenin CD. Rapid Detection of Botulinum Neurotoxins-A Review. Toxins (Basel) 2019; 11:E418. [PMID: 31319550 PMCID: PMC6669533 DOI: 10.3390/toxins11070418] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/15/2019] [Accepted: 07/15/2019] [Indexed: 12/13/2022] Open
Abstract
A toxin is a poisonous substance produced within living cells or organisms. One of the most potent groups of toxins currently known are the Botulinum Neurotoxins (BoNTs). These are so deadly that as little as 62 ng could kill an average human; to put this into context that is approximately 200,000 × less than the weight of a grain of sand. The extreme toxicity of BoNTs leads to the need for methods of determining their concentration at very low levels of sensitivity. Currently the mouse bioassay is the most widely used detection method monitoring the activity of the toxin; however, this assay is not only lengthy, it also has both cost and ethical issues due to the use of live animals. This review focuses on detection methods both existing and emerging that remove the need for the use of animals and will look at three areas; speed of detection, sensitivity of detection and finally cost. The assays will have wide reaching interest, ranging from the pharmaceutical/clinical industry for production quality management or as a point of care sensor in suspected cases of botulism, the food industry as a quality control measure, to the military, detecting BoNT that has been potentially used as a bio warfare agent.
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Affiliation(s)
- Robert J Hobbs
- Applied Research in Chemistry and Health (ARCH) Research Group, School of Natural Sciences, Bangor University, Bangor, Gwynedd, Wales LL57 2UW, UK
| | - Carol A Thomas
- Applied Research in Chemistry and Health (ARCH) Research Group, School of Natural Sciences, Bangor University, Bangor, Gwynedd, Wales LL57 2UW, UK
| | - Jennifer Halliwell
- Applied Research in Chemistry and Health (ARCH) Research Group, School of Natural Sciences, Bangor University, Bangor, Gwynedd, Wales LL57 2UW, UK
| | - Christopher D Gwenin
- Applied Research in Chemistry and Health (ARCH) Research Group, School of Natural Sciences, Bangor University, Bangor, Gwynedd, Wales LL57 2UW, UK.
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7
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Yalamanchili C, Manda VK, Chittiboyina AG, Guernieri RL, Harrell WA, Webb RP, Smith LA, Khan IA. Utilizing Ayurvedic literature for the identification of novel phytochemical inhibitors of botulinum neurotoxin A. JOURNAL OF ETHNOPHARMACOLOGY 2017; 197:211-217. [PMID: 27469199 DOI: 10.1016/j.jep.2016.07.069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/20/2016] [Accepted: 07/25/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Ayurveda, an ancient holistic system of health care practiced on the Indian subcontinent, utilizes a number of multi-plant formulations and is considered by many as a potential source for novel treatments, as well as the identification of new drugs. Our aim is to identify novel phytochemicals for the inhibition of bacterial exotoxin, botulinum neurotoxin A (BoNT/A) based on Ayurvedic literature. BoNT/A is released by Clostridium species, which when ingested, inhibits the release of acetylcholine by concentrating at the neuromuscular junction and causes flaccid paralysis, resulting in a condition termed as botulism, and may also lead to death due to respiratory arrest. METHODS Fifteen plants were selected from the book 'Diagnosis and treatment of diseases in Ayurveda' by Vaidya Bhagwan Dash and Lalitesh Kashyap, based on their frequency of use in the formulations used for the treatment of six diseases with neuromuscular symptoms similar to botulism. Phytochemicals from these plants were screened using in silico, and in vitro methods. Structures of 570 reported phytochemicals from 14 plants were docked inside six reported BoNT/A light chain crystal structures using ensemble docking module in Maestro (Schrödinger, LLE). RESULTS From the docking scores and structural diversity, nine compounds including acoric acid 1, three flavonoids, three coumarins derivatives, one kava lactone were selected and screened using an in vitro HPLC-based protease assay. The bioassay results showed that several compounds possess BoNT/A LC inhibition of 50-60% when compared to positive controls NSC 84094 and CB7967495 (80-95%). CONCLUSION Further testing of the active compounds identified from Ayurvedic literature and structure-activity studies of acoric acid 1 using more sensitive bioassays is under way. The identification of acoric acid 1, a novel scaffold against BoNT/A, exemplifies the utility of Ayurvedic literature for the discovery of novel drug leads.
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Affiliation(s)
- Chinni Yalamanchili
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA; Divison of Pharmacognosy, Department of BioMolecular Sciences, The University of Mississippi, University, MS 38677, USA
| | - Vamshi K Manda
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA
| | - Amar G Chittiboyina
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA
| | - Rebecca L Guernieri
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702-5011, USA
| | - William A Harrell
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702-5011, USA
| | - Robert P Webb
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702-5011, USA
| | - Leonard A Smith
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702-5011, USA
| | - Ikhlas A Khan
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA; Divison of Pharmacognosy, Department of BioMolecular Sciences, The University of Mississippi, University, MS 38677, USA.
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8
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Harris TL, Wenthur CJ, Diego-Taboada A, Mackenzie G, Corbitt TS, Janda KD. Lycopodium clavatum exine microcapsules enable safe oral delivery of 3,4-diaminopyridine for treatment of botulinum neurotoxin A intoxication. Chem Commun (Camb) 2016; 52:4187-90. [PMID: 26906286 DOI: 10.1039/c6cc00615a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
3,4-Diaminopyridine has shown promise in reversing botulinum intoxication, but poor pharmacokinetics and a narrow therapeutic window limit its clinical utility. Thus, we developed a pH-dependent oral delivery platform using club moss spore exines. These exine microcapsules slowed 3,4-diaminopyridine absorption, limited its seizure activity, and enabled delivery of doses which prolonged mouse survival after botulism neurotoxin A intoxication.
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Affiliation(s)
- T L Harris
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
| | - C J Wenthur
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
| | - A Diego-Taboada
- Department of Chemistry, University of Hull, Cottingham Road, Hull HU6 7RX, England and Sporomex Limited, Medina House, 2 Station Avenue, Bridlington, East Yorkshire Y016 4LZ, England
| | - G Mackenzie
- Department of Chemistry, University of Hull, Cottingham Road, Hull HU6 7RX, England and Sporomex Limited, Medina House, 2 Station Avenue, Bridlington, East Yorkshire Y016 4LZ, England
| | - T S Corbitt
- Sporomex Limited, Medina House, 2 Station Avenue, Bridlington, East Yorkshire Y016 4LZ, England
| | - K D Janda
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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9
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Zhou Y, McGillick BE, Teng YHG, Haranahalli K, Ojima I, Swaminathan S, Rizzo RC. Identification of small molecule inhibitors of botulinum neurotoxin serotype E via footprint similarity. Bioorg Med Chem 2016; 24:4875-4889. [PMID: 27543389 DOI: 10.1016/j.bmc.2016.07.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 07/15/2016] [Accepted: 07/16/2016] [Indexed: 11/15/2022]
Abstract
Botulinum neurotoxins (BoNT) are among the most poisonous substances known, and of the 7 serotypes (A-G) identified thus far at least 4 can cause death in humans. The goal of this work was identification of inhibitors that specifically target the light chain catalytic site of the highly pathogenic but lesser-studied E serotype (BoNT/E). Large-scale computational screening, employing the program DOCK, was used to perform atomic-level docking of 1.4 million small molecules to prioritize those making favorable interactions with the BoNT/E site. In particular, 'footprint similarity' (FPS) scoring was used to identify compounds that could potentially mimic features on the known substrate tetrapeptide RIME. Among 92 compounds purchased and experimentally tested, compound C562-1101 emerged as the most promising hit with an apparent IC50 value three-fold more potent than that of the first reported BoNT/E small molecule inhibitor NSC-77053. Additional analysis showed the predicted binding pose of C562-1101 was geometrically and energetically stable over an ensemble of structures generated by molecular dynamic simulations and that many of the intended interactions seen with RIME were maintained. Several analogs were also computationally designed and predicted to have further molecular mimicry thereby demonstrating the potential utility of footprint-based scoring protocols to help guide hit refinement.
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Affiliation(s)
- Yuchen Zhou
- Department of Applied Mathematics & Statistics, Stony Brook University, Stony Brook, NY 11794, United States
| | - Brian E McGillick
- Graduate Program in Biochemistry & Structural Biology, Stony Brook University, Stony Brook, NY 11794, United States; Biology Department, Brookhaven National Laboratory, Upton, NY 11973, United States
| | - Yu-Han Gary Teng
- Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY 11794, United States; Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, United States
| | | | - Iwao Ojima
- Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY 11794, United States; Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, United States
| | | | - Robert C Rizzo
- Department of Applied Mathematics & Statistics, Stony Brook University, Stony Brook, NY 11794, United States; Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY 11794, United States; Laufer Center for Physical & Quantitative Biology, Stony Brook University, Stony Brook, NY 11794, United States.
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10
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Seki H, Xue S, Pellett S, Šilhár P, Johnson EA, Janda KD. Cellular Protection of SNAP-25 against Botulinum Neurotoxin/A: Inhibition of Thioredoxin Reductase through a Suicide Substrate Mechanism. J Am Chem Soc 2016; 138:5568-75. [PMID: 27070533 PMCID: PMC4881748 DOI: 10.1021/jacs.5b12929] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Botulium neurotoxins (BoNTs) are among the most lethal toxins known to man. They are comprised of seven serotypes with BoNT/A being the most deadly; yet, there is no approved therapeutic for their intoxication or one that has even advanced to clinical trials. Botulinum neurotoxicity is ultimately governed through light chain (LC) protease SNARE protein cleavage leading to a loss of neurotransmitter release. Pharmacological attempts to ablate BoNT/A intoxication have sought to either nullify cellular toxin entry or critical biochemical junctions found within its intricate mechanism of action. In these regards, reports have surfaced of nonpeptidic small molecule inhibitors, but few have demonstrated efficacy in neutralizing cellular toxicity, a key prerequisite before rodent lethality studies can be initiated. On the basis of a lead discovered in our BoNT/A cellular assay campaign, we investigated a family of N-hydroxysuccinimide inhibitors grounded upon structure activity relationship (SAR) fundamentals. Molecules stemming from this SAR exercise were theorized to be protease inhibitors. However, this proposition was overturned on the basis of extensive kinetic analysis. Unexpectedly, inhibitor data pointed to thioredoxin reductase (TrxR), an essential component required for BoNT protease translocation. Also unforeseen was the inhibitors' mechanism of action against TrxR, which was found to be brokered through a suicide-mechanism utilizing quinone methide as the inactivating element. This new series of TrxR inhibitors provides an alternative means to negate the etiological agent responsible for BoNT intoxication, the LC protease.
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Affiliation(s)
| | | | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin , 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | | | - Eric A Johnson
- Department of Bacteriology, University of Wisconsin , 1550 Linden Drive, Madison, Wisconsin 53706, United States
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Seki H, Xue S, Hixon MS, Pellett S, Remes M, Johnson EA, Janda KD. Toward the discovery of dual inhibitors for botulinum neurotoxin A: concomitant targeting of endocytosis and light chain protease activity. Chem Commun (Camb) 2015; 51:6226-9. [PMID: 25759983 DOI: 10.1039/c5cc00677e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dyngo-4a™ has been found to be an endocytic inhibitor of BoNT/A neurotoxicity through dynamin inhibition. Herein, we demonstrate this molecule to have a previously unrecognized dual activity against BoNT/A, dynamin-protease inhibition. To establish the importance of this dual activity, detailed kinetic analysis of Dyngo-4a's inhibition of BoNT/A metalloprotease as well as cellular and animal toxicity studies have been described. The research presented is the first polypharmacological approach to counteract BoNT/A intoxication.
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Affiliation(s)
- Hajime Seki
- Departments of Chemistry and Immunology and Microbial Sciences, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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12
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Yiannakopoulou E. Serious and long-term adverse events associated with the therapeutic and cosmetic use of botulinum toxin. Pharmacology 2015; 95:65-9. [PMID: 25613637 DOI: 10.1159/000370245] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/01/2014] [Indexed: 11/19/2022]
Abstract
Although botulinum toxin is generally considered safe, its widespread use and the constantly expanded indications raise safety issues. This study aimed to review the serious and long-term adverse events associated with the therapeutic and cosmetic use of botulinum toxin. Serious adverse events included dysphagia, respiratory compromise, generalized muscle weakness, marked bilateral ptosis, pseudoaneurysm of the frontal branch of the temporal artery, necrotizing fasciitis, sarcoidal granuloma, Fournier gangrene, and cervical kyphosis. Death was attributed to botulism or anaphylactic shock. In conclusion, botulinum toxin may cause serious adverse events, which are more common after its therapeutic use, but can also be noticed after its cosmetic use. Thorough knowledge of the anatomy of the treated muscles and of the pharmacology of the drug is imperative to avoid serious adverse events.
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Affiliation(s)
- Eugenia Yiannakopoulou
- Faculty of Health and Caring Professions, Technological Educational Institute of Athens, Athens, Greece
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13
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Harris TL, Lowery CA, Hixon MS, Janda KD. A platform stratifying a sequestering agent and a pharmacological antagonist as a means to negate botulinum neurotoxicity. ACS Chem Neurosci 2014; 5:632-6. [PMID: 25000171 DOI: 10.1021/cn500135h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Botulinum neurotoxicity is characterized by peripheral neuromuscular blockade/flaccid paralysis that can lead to respiratory failure and ultimately death. Current therapeutic options provide relief in a pre-exposure scenario, but there are no clinically approved postexposure medical countermeasures. Here, we introduce a platform that utilizes a combination of a toxin sequestering agent and a pharmacological antagonist to ablate botulinum neurotoxicity in a well-defined mouse lethality assay. The platform was constructed to allow for ready exchange of sequestering agent and/or pharmacological antagonist for therapeutic optimization. As such, we attempted to improve upon the pharmacological antagonist, a potassium channel blocker, 3,4-diaminopyridine, through a prodrug approach; thus, a complete kinetic decomposition pathway is described. These experiments provide the first proof-of-principle that a synergistic combination strategy can be used to reduce toxin burden in the peripheral using a sequestering antibody, while restoring muscle action via a pharmacological small molecule antagonist.
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Affiliation(s)
- Tyler L. Harris
- Departments
of Chemistry, Immunology and Microbial Sciences, and The Skaggs Institute
for Chemical Biology, The Scripps Research Institute, 10550 North
Torrey Pines Road, La Jolla, California 92037, United States
| | - Colin A. Lowery
- Departments
of Chemistry, Immunology and Microbial Sciences, and The Skaggs Institute
for Chemical Biology, The Scripps Research Institute, 10550 North
Torrey Pines Road, La Jolla, California 92037, United States
| | - Mark S. Hixon
- Department
of Discovery Biology, Takeda California, Inc., 10410 Science Center
Drive, San Diego, California 92121, United States
| | - Kim D. Janda
- Departments
of Chemistry, Immunology and Microbial Sciences, and The Skaggs Institute
for Chemical Biology, The Scripps Research Institute, 10550 North
Torrey Pines Road, La Jolla, California 92037, United States
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14
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Bremer PT, Hixon MS, Janda KD. Benzoquinones as inhibitors of botulinum neurotoxin serotype A. Bioorg Med Chem 2014; 22:3971-81. [PMID: 24984937 DOI: 10.1016/j.bmc.2014.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/31/2014] [Accepted: 06/02/2014] [Indexed: 02/06/2023]
Abstract
Although botulinum neurotoxin serotype A (BoNT/A) is known for its use in cosmetics, it causes a potentially fatal illness, botulism, and can be used as a bioterror weapon. Many compounds have been developed that inhibit the BoNTA zinc-metalloprotease light chain (LC), however, none of these inhibitors have advanced to clinical trials. In this study, a fragment-based approach was implemented to develop novel covalent inhibitors of BoNT/A LC. First, electrophilic fragments were screened against BoNT/A LC, and benzoquinone (BQ) derivatives were found to be active. In kinetic studies, BQ compounds acted as irreversible inhibitors that presumably covalently modify cysteine 165 of BoNT/A LC. Although most BQ derivatives were highly reactive toward glutathione in vitro, a few compounds such as natural product naphthazarin displayed low thiol reactivity and good BoNT/A inhibition. In order to increase the potency of the BQ fragment, computational docking studies were employed to elucidate a scaffold that could bind to sites adjacent to Cys165 while positioning a BQ fragment at Cys165 for covalent modification; 2-amino-N-arylacetamides met these criteria and when linked to BQ displayed at least a 20-fold increase in activity to low μM IC₅₀ values. Unlike BQ alone, the linked-BQ compounds demonstrated only weak irreversible inhibition and therefore acted mainly as non-covalent inhibitors. Further kinetic studies revealed a mutual exclusivity of BQ covalent inactivation and competitive inhibitor binding to sites adjacent to Cys165, refuting the viability of the current strategy for developing more potent irreversible BoNT/A inhibitors. The highlights of this study include the discovery of BQ compounds as irreversible BoNT/A inhibitors and the rational design of low μM IC50 competitive inhibitors that depend on the BQ moiety for activity.
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Affiliation(s)
- Paul T Bremer
- Departments of Chemistry and Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Mark S Hixon
- Discovery Biology, Takeda San Diego, Inc., 10410 Science Center Drive, San Diego, CA 92121, USA
| | - Kim D Janda
- Departments of Chemistry and Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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15
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Videnović M, Opsenica DM, Burnett J, Gomba L, Nuss JE, Selaković Ž, Konstantinović J, Krstić M, Šegan S, Zlatović M, Sciotti RJ, Bavari S, Šolaja BA. Second generation steroidal 4-aminoquinolines are potent, dual-target inhibitors of the botulinum neurotoxin serotype A metalloprotease and P. falciparum malaria. J Med Chem 2014; 57:4134-53. [PMID: 24742203 PMCID: PMC4032193 DOI: 10.1021/jm500033r] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Indexed: 01/25/2023]
Abstract
Significantly more potent second generation 4-amino-7-chloroquinoline (4,7-ACQ) based inhibitors of the botulinum neurotoxin serotype A (BoNT/A) light chain were synthesized. Introducing an amino group at the C(3) position of the cholate component markedly increased potency (IC50 values for such derivatives ranged from 0.81 to 2.27 μM). Two additional subclasses were prepared: bis(steroidal)-4,7-ACQ derivatives and bis(4,7-ACQ)cholate derivatives; both classes provided inhibitors with nanomolar-range potencies (e.g., the Ki of compound 67 is 0.10 μM). During BoNT/A challenge using primary neurons, select derivatives protected SNAP-25 by up to 89%. Docking simulations were performed to rationalize the compounds' in vitro potencies. In addition to specific residue contacts, coordination of the enzyme's catalytic zinc and expulsion of the enzyme's catalytic water were a consistent theme. With respect to antimalarial activity, the compounds provided better IC90 activities against chloroquine resistant (CQR) malaria than CQ, and seven compounds were more active than mefloquine against CQR strain W2.
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Affiliation(s)
- Milica Videnović
- Faculty
of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
| | - Dejan M. Opsenica
- Institute
of Chemistry, Technology, and Metallurgy, University of Belgrade, Njegoseva 12, 11000 Belgrade, Serbia
| | - James
C. Burnett
- Computational
Drug Development Group, Leidos Biomedical
Research, Inc., FNLCR at Frederick, P.O.
Box B, Frederick, Maryland 21701, United States
| | - Laura Gomba
- Department
of Bacteriology, United States Army Medical
Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, Maryland 21702, United States
| | - Jonathan E. Nuss
- Department
of Bacteriology, United States Army Medical
Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, Maryland 21702, United States
| | - Života Selaković
- Faculty
of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
| | - Jelena Konstantinović
- Faculty
of Chemistry Innovative Centre, Studentski trg 12-16, 11158 Belgrade, Serbia
| | - Maja Krstić
- Faculty
of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
| | - Sandra Šegan
- Institute
of Chemistry, Technology, and Metallurgy, University of Belgrade, Njegoseva 12, 11000 Belgrade, Serbia
| | - Mario Zlatović
- Faculty
of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
| | - Richard J. Sciotti
- Division
of Experimental Therapeutics, Walter Reed
Army Institute of Research, Silver
Spring, Maryland 20910, United States
| | - Sina Bavari
- Target
Discovery and Experimental Microbiology, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, Maryland 21702, United States
| | - Bogdan A. Šolaja
- Faculty
of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
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16
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Caglič D, Krutein MC, Bompiani KM, Barlow DJ, Benoni G, Pelletier JC, Reitz AB, Lairson LL, Houseknecht KL, Smith GR, Dickerson TJ. Identification of clinically viable quinolinol inhibitors of botulinum neurotoxin A light chain. J Med Chem 2014; 57:669-76. [PMID: 24387280 PMCID: PMC3983388 DOI: 10.1021/jm4012164] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Botulinum neurotoxins (BoNT) are the most potent toxins known and a significant bioterrorist threat. Few small molecule compounds have been identified that are active in cell-based or animal models, potentially due to toxin enzyme plasticity. Here we screened commercially available quinolinols, as well as synthesized hydroxyquinolines. Seventy-two compounds had IC50 values below 10 μM, with the best compound exhibiting submicromolar inhibition (IC50 = 0.8 μM). Structure-activity relationship trends showed that the enzyme tolerates various substitutions at R1 but has a clear preference for bulky aryl amide groups at R2, while methylation at R3 increased inhibitor potency. Evaluation of the most potent compounds in an ADME panel showed that these compounds possess poor solubility at pH 6.8, but display excellent solubility at low pH, suggesting that oral dosing may be possible. Our data show the potential of quinolinol compounds as BoNT therapeutics due to their good in vitro potencies and favorable ADME properties.
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Affiliation(s)
- Dejan Caglič
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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17
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Caglič D, Bompiani KM, Krutein MC, Čapek P, Dickerson TJ. A high-throughput-compatible FRET-based platform for identification and characterization of botulinum neurotoxin light chain modulators. J Vis Exp 2013:50908. [PMID: 24430674 DOI: 10.3791/50908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Botulinum neurotoxin (BoNT) is a potent and potentially lethal bacterial toxin that binds to host motor neurons, is internalized into the cell, and cleaves intracellular proteins that are essential for neurotransmitter release. BoNT is comprised of a heavy chain (HC), which mediates host cell binding and internalization, and a light chain (LC), which cleaves intracellular host proteins essential for acetylcholine release. While therapies that inhibit toxin binding/internalization have a small time window of administration, compounds that target intracellular LC activity have a much larger time window of administrations, particularly relevant given the extremely long half-life of the toxin. In recent years, small molecules have been heavily analyzed as potential LC inhibitors based on their increased cellular permeability relative to larger therapeutics (peptides, aptamers, etc.). Lead identification often involves high-throughput screening (HTS), where large libraries of small molecules are screened based on their ability to modulate therapeutic target function. Here we describe a FRET-based assay with a commercial BoNT/A LC substrate and recombinant LC that can be automated for HTS of potential BoNT inhibitors. Moreover, we describe a manual technique that can be used for follow-up secondary screening, or for comparing the potency of several candidate compounds.
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Affiliation(s)
- Dejan Caglič
- Department of Chemistry, The Scripps Research Institute
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18
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Lowery CA, Adler M, Borrell A, Janda KD. Scorpion toxins for the reversal of BoNT-induced paralysis. Bioorg Med Chem Lett 2013; 23:6743-6. [PMID: 24252544 DOI: 10.1016/j.bmcl.2013.10.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 10/15/2013] [Accepted: 10/17/2013] [Indexed: 11/15/2022]
Abstract
The botulinum neurotoxins, characterized by their neuromuscular paralytic effects, are the most toxic proteins known to man. Due to their extreme potency, ease of production, and duration of activity, the BoNT proteins have been classified by the Centers for Disease Control as high threat agents for bioterrorism. In an attempt to discover effective BoNT therapeutics, we have pursued a strategy in which we leverage the blockade of K(+) channels that ultimately results in the reversal of neuromuscular paralysis. Towards this end, we utilized peptides derived from scorpion venom that are highly potent K(+) channel blockers. Herein, we report the synthesis of charybdotoxin, a 37 amino acid peptide, and detail its activity, along with iberiotoxin and margatoxin, in a mouse phrenic nerve hemidiaphragm assay in the absence and the presence of BoNT/A.
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Affiliation(s)
- Colin A Lowery
- Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Department of Immunology and Microbial Sciences, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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19
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Seki H, Pellett S, Silhár P, Stowe GN, Blanco B, Lardy MA, Johnson EA, Janda KD. Synthesis/biological evaluation of hydroxamic acids and their prodrugs as inhibitors for Botulinum neurotoxin A light chain. Bioorg Med Chem 2013; 22:1208-17. [PMID: 24360826 DOI: 10.1016/j.bmc.2013.11.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/28/2013] [Indexed: 01/03/2023]
Abstract
Botulinum neurotoxin A (BoNT/A) is the most potent toxin known. Unfortunately, it is also a potential bioweapon in terrorism, which is without an approved therapeutic treatment once cellular intoxication takes place. Previously, we reported how hydroxamic acid prodrug carbamates increased cellular uptake, which translated to successful inhibition of this neurotoxin. Building upon this research, we detail BoNT/A protease molecular modeling studies accompanied by the construction of small library of hydroxamic acids based on 2,4-dichlorocinnamic hydroxamic acid scaffold and their carbamate prodrug derivatization along with the evaluation of these molecules in both enzymatic and cellular models.
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Affiliation(s)
- Hajime Seki
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin, 1550 Linden Drive, Madison, WI 53706, United States
| | - Peter Silhár
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - G Neil Stowe
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Beatriz Blanco
- Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Universidad de Santiago de Compostela, calle Jenaro de la Fuente s/n, 15782 Santiago de Compostela, Spain
| | - Matthew A Lardy
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Eric A Johnson
- Department of Bacteriology, University of Wisconsin, 1550 Linden Drive, Madison, WI 53706, United States
| | - Kim D Janda
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States; Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States.
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20
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Silhár P, Eubanks LM, Seki H, Pellett S, Javor S, Tepp WH, Johnson EA, Janda KD. Targeting botulinum A cellular toxicity: a prodrug approach. J Med Chem 2013; 56:7870-9. [PMID: 24127873 DOI: 10.1021/jm400873n] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The botulinum neurotoxin light chain (LC) protease has become an important therapeutic target for postexposure treatment of botulism. Hydroxamic acid based small molecules have proven to be potent inhibitors of LC/A with nanomolar Ki values, yet they lack cellular activity conceivably due to low membrane permeability. To overcome this potential liability, we investigated two prodrug strategies, 1,4,2-dioxazole and carbamate, based on our 1-adamantylacetohydroxamic acid scaffold. The 1,4,2-dioxazole prodrug did not demonstrate cellular activity, however, carbamates exhibited cellular potency with the most active compound displaying an EC50 value of 20 μM. Cellular trafficking studies were conducted using a "fluorescently silent" prodrug that remained in this state until cellular uptake was complete, which allowed for visualization of the drug's release inside neuronal cells. In sum, this research sets the stage for future studies leveraging the specific targeting and delivery of these prodrugs, as well as other antibotulinum agents, into neuronal cells.
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Affiliation(s)
- Peter Silhár
- Departments of Chemistry and Immunology and Microbial Science, The Skaggs Institute for Chemical Biology, and The Worm Institute for Research and Medicine, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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21
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Opsenica IM, Tot M, Gomba L, Nuss JE, Sciotti RJ, Bavari S, Burnett JC, Šolaja BA. 4-Amino-7-chloroquinolines: probing ligand efficiency provides botulinum neurotoxin serotype A light chain inhibitors with significant antiprotozoal activity. J Med Chem 2013; 56:5860-71. [PMID: 23815186 PMCID: PMC3880596 DOI: 10.1021/jm4006077] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structurally simplified analogues of dual antimalarial and botulinum neurotoxin serotype A light chain (BoNT/A LC) inhibitor bis-aminoquinoline (1) were prepared. New compounds were designed to improve ligand efficiency while maintaining or exceeding the inhibitory potency of 1. Three of the new compounds are more active than 1 against both indications. Metabolically, the new inhibitors are relatively stable and nontoxic. 12, 14, and 15 are more potent BoNT/A LC inhibitors than 1. Additionally, 15 has excellent in vitro antimalarial efficacy, with IC90 values ranging from 4.45 to 12.11 nM against five Plasmodium falciparum (P.f.) strains: W2, D6, C235, C2A, and C2B. The results indicate that the same level of inhibitory efficacy provided by 1 can be retained/exceeded with less structural complexity. 12, 14, and 15 provide new platforms for the development of more potent dual BoNT/A LC and P.f. inhibitors adhering to generally accepted chemical properties associated with the druggability of synthetic molecules.
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Affiliation(s)
- Igor M. Opsenica
- Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
| | - Mikloš Tot
- Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
| | - Laura Gomba
- United States Army Medical Research Institute of Infectious Diseases, Department of Bacteriology, 1425 Porter Street, Frederick, MD 21702, USA
| | - Jonathan E. Nuss
- United States Army Medical Research Institute of Infectious Diseases, Department of Bacteriology, 1425 Porter Street, Frederick, MD 21702, USA
| | - Richard J. Sciotti
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
| | - Sina Bavari
- Target Discovery and Experimental Microbiology, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA
| | - James C. Burnett
- Computational Drug Development Group, SAIC-Frederick, Inc., FNLCR at Frederick, P.O. Box B, Frederick, Maryland, United States
| | - Bogdan A. Šolaja
- Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
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22
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Lungu C, Considine E, Zahir S, Ponsati B, Arrastia S, Hallett M. Pilot study of topical acetyl hexapeptide-8 in the treatment for blepharospasm in patients receiving botulinum toxin therapy. Eur J Neurol 2013; 20:515-518. [PMID: 23146065 PMCID: PMC4747634 DOI: 10.1111/ene.12009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/10/2012] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND PURPOSE Injectable botulinum neurotoxin (BoNT) is the principal effective treatment for blepharospasm (BSP). This trial explores the safety and efficacy of topical acetyl hexapeptide-8 (AH8), a competitive SNAP25 inhibitor, as a potential new therapy in BSP. METHODS Double-blind, placebo-controlled, randomized trial of daily topical application of AH8 in 24 patients with BSP. The primary outcome was time to return to baseline Jankovic Blepharospasm Rating Scale (JBRS) after a BoNT injection simultaneously with the initiation of AH8. Patients displaying a strictly regular pattern of response to 3-monthly injections of BoNT were included. RESULTS There were no significant adverse events. There was a trend for longer time until return to baseline JBRS after injection in the active group compared to placebo (3.7 months vs. 3.0 months), and for better scores in the active group. One-third (4/12) of the patients in the active group had a considerable extension of symptom control after BoNT (range: 3.3-7.1 months). CONCLUSIONS Topical AH8 is safe and promising for extending the duration of action of BoNT therapy for BSP.
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Affiliation(s)
- Codrin Lungu
- Office of the Clinical Director, NINDS, NIH, Bethesda, MD
| | - Elaine Considine
- Human Motor Control Section, Medical Neurology Branch, NINDS, NIH, Bethesda, MD
| | - Sana Zahir
- Office of the Clinical Director, NINDS, NIH, Bethesda, MD
| | | | | | - Mark Hallett
- Human Motor Control Section, Medical Neurology Branch, NINDS, NIH, Bethesda, MD
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23
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Šilhár P, Lardy MA, Hixon MS, Shoemaker CB, Barbieri JT, Struss AK, Lively JM, Javor S, Janda KD. The C-terminus of Botulinum A Protease Has Profound and Unanticipated Kinetic Consequences Upon the Catalytic Cleft. ACS Med Chem Lett 2013; 4:283-287. [PMID: 23565325 DOI: 10.1021/ml300428s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are among the most deadly poisons known though ironically, they also are of great therapeutic utility. A number of research programs have been initiated to discover small molecule inhibitors of BoNTs metalloprotease activity. Many, though not all of these programs have screened against a truncated and more stable form of the enzyme, that possess comparable catalytic properties to the full length enzyme. Interestingly, several classes of inhibitors notably the hydroxamates, display a large shift in potency between the two enzyme forms. In this report we compare the kinetics of active-site, alpha-exosite and beta-exosite inhibitors versus truncated and full length enzyme. Molecular dynamics simulations conducted with the truncated and homology models of the fully length BoNT LC/A indicate the flexibility of the C-terminus of the full length enzyme is responsible for the potency shifts of active-site proximally binding inhibitors while distal binding (alpha-exosite) inhibitors remain equipotent.
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Affiliation(s)
- Peter Šilhár
- Departments of Chemistry and
Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey
Pines Road, La Jolla, California 92037, United States
| | - Matthew A. Lardy
- Takeda California Inc., 10410 Science Center Drive, San Diego, California
92121, United States
| | - Mark S. Hixon
- Takeda California Inc., 10410 Science Center Drive, San Diego, California
92121, United States
| | - Charles B. Shoemaker
- Department
of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, 200 Westboro
Road, North Grafton, Massachusetts 01536, United States
| | - Joseph T. Barbieri
- Department of Microbiology and
Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Anjali K. Struss
- Departments of Chemistry and
Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey
Pines Road, La Jolla, California 92037, United States
| | - Jenny M. Lively
- Departments of Chemistry and
Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey
Pines Road, La Jolla, California 92037, United States
| | - Sacha Javor
- Departments of Chemistry and
Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey
Pines Road, La Jolla, California 92037, United States
| | - Kim D. Janda
- Departments of Chemistry and
Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey
Pines Road, La Jolla, California 92037, United States
- Worm Institute for Research
and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United
States
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24
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Šilhár P, Silvaggi NR, Pellett S, Čapková K, Johnson EA, Allen KN, Janda KD. Evaluation of adamantane hydroxamates as botulinum neurotoxin inhibitors: synthesis, crystallography, modeling, kinetic and cellular based studies. Bioorg Med Chem 2012; 21:1344-8. [PMID: 23340139 DOI: 10.1016/j.bmc.2012.12.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/01/2012] [Accepted: 12/03/2012] [Indexed: 10/27/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the most lethal biotoxins known to mankind and are responsible for the neuroparalytic disease botulism. Current treatments for botulinum poisoning are all protein based and thus have a limited window of treatment opportunity. Inhibition of the BoNT light chain protease (LC) has emerged as a therapeutic strategy for the treatment of botulism as it may provide an effective post exposure remedy. Using a combination of crystallographic and modeling studies a series of hydroxamates derived from 1-adamantylacetohydroxamic acid (3a) were prepared. From this group of compounds, an improved potency of about 17-fold was observed for two derivatives. Detailed mechanistic studies on these structures revealed a competitive inhibition model, with a K(i)=27 nM, which makes these compounds some of the most potent small molecule, non-peptidic BoNT/A LC inhibitors reported to date.
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Affiliation(s)
- Peter Šilhár
- Department of Chemistry, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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25
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Stura EA, Le Roux L, Guitot K, Garcia S, Bregant S, Beau F, Vera L, Collet G, Ptchelkine D, Bakirci H, Dive V. Structural framework for covalent inhibition of Clostridium botulinum neurotoxin A by targeting Cys165. J Biol Chem 2012; 287:33607-14. [PMID: 22869371 DOI: 10.1074/jbc.m112.396697] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Clostridium botulinum neurotoxin type A (BoNT/A) is one of the most potent toxins for humans and a major biothreat agent. Despite intense chemical efforts over the past 10 years to develop inhibitors of its catalytic domain (catBoNT/A), highly potent and selective inhibitors are still lacking. Recently, small inhibitors were reported to covalently modify catBoNT/A by targeting Cys(165), a residue located in the enzyme active site just above the catalytic zinc ion. However, no direct proof of Cys(165) modification was reported, and the poor accessibility of this residue in the x-ray structure of catBoNT/A raises concerns about this proposal. To clarify this issue, the functional role of Cys(165) was first assessed through a combination of site-directed mutagenesis and structural studies. These data suggested that Cys(165) is more involved in enzyme catalysis rather than in structural property. Then by peptide mass fingerprinting and x-ray crystallography, we demonstrated that a small compound containing a sulfonyl group acts as inhibitor of catBoNT/A through covalent modification of Cys(165). The crystal structure of this covalent complex offers a structural framework for developing more potent covalent inhibitors catBoNT/A. Other zinc metalloproteases can be founded in the protein database with a cysteine at a similar location, some expressed by major human pathogens; thus this work should find broader applications for developing covalent inhibitors.
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Affiliation(s)
- Enrico A Stura
- Commissariat à l'Energie Atomique, iBiTec-S, Service d'Ingénierie Moléculaire des Protéines, CE-Saclay, 91191 Gif-sur-Yvette, Cedex, France
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26
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Opsenica I, Filipovic V, Nuss JE, Gomba LM, Opsenica D, Burnett JC, Gussio R, Solaja BA, Bavari S. The synthesis of 2,5-bis(4-amidinophenyl)thiophene derivatives providing submicromolar-range inhibition of the botulinum neurotoxin serotype A metalloprotease. Eur J Med Chem 2012; 53:374-9. [PMID: 22516424 PMCID: PMC3361628 DOI: 10.1016/j.ejmech.2012.03.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 02/22/2012] [Accepted: 03/25/2012] [Indexed: 10/28/2022]
Abstract
Botulinum neurotoxins (BoNTs), composed of a family of seven serotypes (categorized A-G), are the deadliest of known biological toxins. The activity of the metalloprotease, light chain (LC) component of the toxins is responsible for causing the life-threatening paralysis associated with the disease botulism. Herein we report significantly more potent analogs of novel, lead BoNT serotype A LC inhibitor 2,5-bis(4-amidinophenyl)thiophene (K(i) = 10.88 μM ± 0.90 μM). Specifically, synthetic modifications involved simultaneously replacing the lead inhibitor's terminal bis-amidines with secondary amines and the systematic tethering of 4-amino-7-chloroquinoline substituents to provide derivatives with K(i) values ranging from 0.302 μM (± 0.03 μM) to 0.889μM (± 0.11 μM).
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Affiliation(s)
- Igor Opsenica
- Faculty of Chemistry, University of Belgrade, Studentski trg16, P.O. Box 51, Belgrade, Serbia
| | - Vuk Filipovic
- Faculty of Chemistry, University of Belgrade, Studentski trg16, P.O. Box 51, Belgrade, Serbia
| | - Jon E. Nuss
- United States Army Medical Research Institute of Infectious Diseases, Department of Bacteriology, 1425 Porter Street, Frederick, MD 21702, USA
| | - Laura M. Gomba
- United States Army Medical Research Institute of Infectious Diseases, Department of Bacteriology, 1425 Porter Street, Frederick, MD 21702, USA
| | - Dejan Opsenica
- Institute of Chemistry, Technology, and Metallurgy, 12 Njegoseva 12, 11001, P.O. Box 473, Belgrade, Serbia
| | - James C. Burnett
- SAIC-Frederick, Inc., National Cancer Institute at Frederick, Target Structure-Based Drug Discovery Group, P.O. Box B, Frederick, MD 21702, USA
| | - Rick Gussio
- National Cancer Institute at Frederick, Developmental Therapeutics Program, P.O. Box B, Frederick, MD 21702, USA
| | - Bogdan A. Solaja
- Faculty of Chemistry, University of Belgrade, Studentski trg16, P.O. Box 51, Belgrade, Serbia
| | - Sina Bavari
- Chief, Target Discovery and Experimental Microbiology, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA
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27
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Smith GR, Caglič D, Capek P, Zhang Y, Godbole S, Reitz AB, Dickerson TJ. Reexamining hydroxamate inhibitors of botulinum neurotoxin serotype A: extending towards the β-exosite. Bioorg Med Chem Lett 2012; 22:3754-7. [PMID: 22542019 DOI: 10.1016/j.bmcl.2012.04.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 04/03/2012] [Indexed: 10/28/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the most toxic proteins known to man, exposure to which results in flaccid paralysis. Given their extreme potency, these proteins have become studied as possible weapons of bioterrorism; however, effective treatments that function after intoxication have not progressed to the clinic. Here, we have reexamined one of the most effective inhibitors, 2,4-dichlorocinnamyl hydroxamate, in the context of the known plasticity of the BoNT/A light chain metalloprotease. Our studies have shown that modifications of this compound are tolerated and result in improved inhibitors, with the best compound having an IC(50) of 0.23 μM. Given the inconsistency of structure-activity relationship trends observed across similar compounds, this data argues for caution in extrapolating across structural series.
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Affiliation(s)
- Garry R Smith
- Fox Chase Chemical Diversity Center, Doylestown, PA 18902, USA
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28
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Caglič D, Dickerson TJ. A coincidence detector triggers botulinum neurotoxin translocation. Future Microbiol 2012; 7:185-8. [PMID: 22324987 DOI: 10.2217/fmb.11.157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the deadliest poisons known to man. They possess a particular duality, rapidly increasing clinical utility for a wide range of disorders and large concern as a possible weapon of bioterrorism. While great strides have been made in the structural and biochemical understanding of the mechanism of intoxication, the specific molecular details behind BoNT translocation out of endosomes remain elusive. In this study, it was conclusively demonstrated that light chain metalloprotease translocation can only occur in the presence of low pH, as is found in endosomes, and GT1b ganglioside coreceptor, whose role was previously thought to only be in cell surface recognition by the toxin. As stated by the authors, the BoNT receptor-binding domain therefore serves as a 'coincidence receptor' in that pH sensing and conformational change to a translocation competent form must be coupled in some way to receptor binding. Further study using atomic force microscopy also suggested the presence of oligomeric toxin channels that can be inhibited by the natural product toosendanin. This data revises the model of BoNT intoxication and demonstrates a mechanism for the amazing temporal and spatial control possessed by this toxin, which ultimately manifests in its extreme potency.
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Affiliation(s)
- Dejan Caglič
- Department of Chemistry & Worm Institute of Research & Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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29
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Fang XF, Cui ZJ. The anti-botulism triterpenoid toosendanin elicits calcium increase and exocytosis in rat sensory neurons. Cell Mol Neurobiol 2011; 31:1151-62. [PMID: 21656151 DOI: 10.1007/s10571-011-9716-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 05/20/2011] [Indexed: 02/07/2023]
Abstract
Toosendanin, a triterpenoid from Melia toosendan Sieb et Zucc, has been found before to be an effective anti-botulism agent, with a bi-phasic effect at both motor nerve endings and central synapse: an initial facilitation followed by prolonged depression. Initial facilitation may be due to activation of voltage-dependent calcium channels plus inhibition of potassium channels, but the depression is not fully understood. Toosendanin has no effect on intracellular calcium or secretion in the non-excitable pancreatic acinar cells, ruling out general toosendanin inhibition of exocytosis. In this study, toosendanin effects on sensory neurons isolated from rat nodose ganglia were investigated. It was found that toosendanin stimulated increases in cytosolic calcium and neuronal exocytosis dose dependently. Experiments with membrane potential indicator bis-(1,3-dibutylbarbituric acid)trimethine oxonol found that toosendanin hyperpolarized capsaicin-insensitive but depolarized capsaicin-sensitive neurons; high potassium-induced calcium increase was much smaller in hyperpolarizing neurons than in depolarizing neurons, whereas no difference was found for potassium-induced depolarization in these two types of neurons. In neurons showing spontaneous calcium oscillations, toosendanin increased the oscillatory amplitude but not frequency. Toosendanin-induced calcium increase was decreased in calcium-free buffer, by nifedipine, and by transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine. Simultaneous measurements of cytosolic and endoplasmic reticulum (ER) calcium showed an increase in cytosolic but a decrease in ER calcium, indicating that toosendanin triggered ER calcium release. These data together indicate that toosendanin modulates sensory neurons, but had opposite effects on membrane potential depending on the presence or absence of capsaicin receptor/TRPV 1 channel.
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Affiliation(s)
- Xiao Feng Fang
- Institute of Cell Biology, Beijing Normal University, Beijing 100875, China
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30
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Zakhari JS, Kinoyama I, Hixon MS, Di Mola A, Globisch D, Janda KD. Formulating a new basis for the treatment against botulinum neurotoxin intoxication: 3,4-Diaminopyridine prodrug design and characterization. Bioorg Med Chem 2011; 19:6203-9. [PMID: 21975066 DOI: 10.1016/j.bmc.2011.09.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/08/2011] [Indexed: 10/17/2022]
Abstract
Botulism is a disease characterized by neuromuscular paralysis and is produced from botulinum neurotoxins (BoNTs) found within the Gram positive bacterium Clostridium botulinum. This bacteria produces the most deadliest toxin known, with lethal doses as low as 1 ng/kg. Due to the relative ease of production and transport, the use of these agents as potential bioterrorist weapons has become of utmost concern. No small molecule therapies against BoNT intoxication have been approved to date. However, 3,4-diaminopyridine (3,4-DAP), a potent reversible inhibitor of voltage-gated potassium channels, is an effective cholinergic agonist used in the treatment of neuromuscular degenerative disorders that require cholinergic enhancement. 3,4-DAP has also been shown to facilitate recovery of neuromuscular action potential post botulinum intoxication by blocking K(+) channels. Unfortunately, 3,4-DAP displays toxicity largely due to blood-brain-barrier (BBB) penetration. As a dual-action prodrug approach to cholinergic enhancement we have designed carbamate and amide conjugates of 3,4-DAP. The carbamate prodrug is intended to be a slowly reversible inhibitor of acetylcholinesterase (AChE) along the lines of the stigmines thereby allowing increased persistence of released acetylcholine within the synaptic cleft. As a secondary activity, cleavage of the carbamate prodrug by AChE will afford the localized release of 3,4-DAP, which in turn, will enhance the pre-synaptic release of additional acetylcholine. Being a competitive inhibitor with respect to acetylcholine, the activity of the prodrug will be greatest at the synaptic junctions most depleted of acetylcholine. Here we report upon the synthesis and biochemical characterization of three new classes of prodrugs intended to limit previously reported stability and toxicity issues. Of the prodrugs examined, compound 32, demonstrated the most clinically relevant half-life of 2.76 h, while selectively inhibiting AChE over butyrylcholinesterase--a plasma-based high activity esterase. Future in vivo studies could provide validation of prodrug 32 as a potential treatment against BoNT intoxication as well as other neuromuscular disorders.
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Affiliation(s)
- Joseph S Zakhari
- Department of Chemistry, Immunology and Microbial Sciences, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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31
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Thompson AA, Jiao GS, Kim S, Thai A, Cregar-Hernandez L, Margosiak SA, Johnson AT, Han GW, O’Malley S, Stevens RC. Structural characterization of three novel hydroxamate-based zinc chelating inhibitors of the Clostridium botulinum serotype A neurotoxin light chain metalloprotease reveals a compact binding site resulting from 60/70 loop flexibility. Biochemistry 2011; 50:4019-28. [PMID: 21434688 PMCID: PMC3092028 DOI: 10.1021/bi2001483] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Neurotoxins synthesized by Clostridium botulinum bacteria (BoNT), the etiological agent of human botulism, are extremely toxic proteins making them high-risk agents for bioterrorism. Small molecule inhibitor development has been focused on the light chain zinc-dependent metalloprotease domain of the neurotoxin, an effort that has been hampered by its relatively flexible active site. Developed in concert with structure--activity relationship studies, the X-ray crystal structures of the complex of BoNT serotype A light chain (BoNT/A LC) with three different micromolar-potency hydroxamate-based inhibitors are reported here. Comparison with an unliganded BoNT/A LC structure reveals significant changes in the active site as a result of binding by the unique inhibitor scaffolds. The 60/70 loop at the opening of the active site pocket undergoes the largest conformational change, presumably through an induced-fit mechanism, resulting in the most compact catalytic pocket observed in all known BoNT/A LC structures.
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Affiliation(s)
- Aaron A. Thompson
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Guan-Sheng Jiao
- Department of Chemistry, PanThera Biopharma LLC, Aiea, HI 96701
| | - Seongjin Kim
- Department of Chemistry, PanThera Biopharma LLC, Aiea, HI 96701
| | - April Thai
- Department of Chemistry, PanThera Biopharma LLC, Aiea, HI 96701
| | | | | | - Alan T. Johnson
- Department of Chemistry, PanThera Biopharma LLC, Aiea, HI 96701
| | - Gye Won Han
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Sean O’Malley
- Department of Chemistry, PanThera Biopharma LLC, Aiea, HI 96701
| | - Raymond C. Stevens
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037,Address correspondence to: The Scripps Research Institute, 10550 North Torrey Pines Rd., GAC-1200, La Jolla, CA 92037. Tel.: 858-784-9416; Fax: 858-784-9483;
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32
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Opsenica I, Burnett JC, Gussio R, Opsenica D, Todorović N, Lanteri CA, Sciotti RJ, Gettayacamin M, Basilico N, Taramelli D, Nuss JE, Wanner L, Panchal RG, Šolaja BA, Bavari S. A chemotype that inhibits three unrelated pathogenic targets: the botulinum neurotoxin serotype A light chain, P. falciparum malaria, and the Ebola filovirus. J Med Chem 2011; 54:1157-69. [PMID: 21265542 PMCID: PMC3056319 DOI: 10.1021/jm100938u] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A 1,7-bis(alkylamino)diazachrysene-based small molecule was previously identified as an inhibitor of the botulinum neurotoxin serotype A light chain metalloprotease. Subsequently, a variety of derivatives of this chemotype were synthesized to develop structure-activity relationships, and all are inhibitors of the BoNT/A LC. Three-dimensional analyses indicated that half of the originally discovered 1,7-DAAC structure superimposed well with 4-amino-7-chloroquinoline-based antimalarial agents. This observation led to the discovery that several of the 1,7-DAAC derivatives are potent in vitro inhibitors of Plasmodium falciparum and, in general, are more efficacious against CQ-resistant strains than against CQ-susceptible strains. In addition, by inhibiting β-hematin formation, the most efficacious 1,7-DAAC-based antimalarials employ a mechanism of action analogous to that of 4,7-ACQ-based antimalarials and are well tolerated by normal cells. One candidate was also effective when administered orally in a rodent-based malaria model. Finally, the 1,7-DAAC-based derivatives were examined for Ebola filovirus inhibition in an assay employing Vero76 cells, and three provided promising antiviral activities and acceptably low toxicities.
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Affiliation(s)
- Igor Opsenica
- Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
| | - James C. Burnett
- Target Structure-Based Drug Discovery Group, SAIC-Frederick, Inc., National Cancer Institute at Frederick, P.O. Box B, Frederick, MD 21702, USA
| | - Rick Gussio
- Developmental Therapeutics Program, National Cancer Institute at Frederick, P.O. Box B, F.V.C. 310, Frederick, MD 21702, USA
| | - Dejan Opsenica
- Institute of Chemistry, Technology, and Metallurgy, Belgrade, Serbia
| | - Nina Todorović
- Institute of Chemistry, Technology, and Metallurgy, Belgrade, Serbia
| | - Charlotte A. Lanteri
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Richard J. Sciotti
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Montip Gettayacamin
- United States Army Medical Component, Armed Forces Research Institute of Medical Science, Department of Veterinary Medicine, Bangkok, Thailand
| | - Nicoletta Basilico
- Dipartimento di Sanità Pubblica- Microbiologia-Virologia, Università di Milano, Via Pascal 36, 20133 Milano, Italy
| | - Donatella Taramelli
- Dipartimento di Sanità Pubblica- Microbiologia-Virologia, Università di Milano, Via Pascal 36, 20133 Milano, Italy
| | - Jonathan E. Nuss
- United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702; USA
| | - Laura Wanner
- United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702; USA
| | - Rekha G. Panchal
- United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702; USA
| | - Bogdan A. Šolaja
- Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158, Belgrade, Serbia
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702; USA
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33
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Šilhár P, Alakurtti S, Čapková K, Xiaochuan F, Shoemaker CB, Yli-Kauhaluoma J, Janda KD. Synthesis and evaluation of library of betulin derivatives against the botulinum neurotoxin A protease. Bioorg Med Chem Lett 2011; 21:2229-31. [PMID: 21421315 DOI: 10.1016/j.bmcl.2011.02.115] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 02/25/2011] [Accepted: 02/28/2011] [Indexed: 10/18/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the most toxic proteins currently known. Current treatments for botulinum poisoning are all protein based with a limited window of opportunity. Inhibition of the BoNT light chain protease (LC) has emerged as a new therapeutic strategy for the treatment of botulism as it may provide an effective post-exposure remedy. As such, a small library of 40 betulin derivatives was synthesized and screened against the light chain of BoNT serotype A (LC/A); five positive hits (IC(50) <100 μM) were uncovered. Detailed evaluation of inhibition mechanism of three most active compounds revealed a competitive model, with sub-micromolar K(i) value for the best inhibitor (7). Unfortunately, an in vitro cell-based assay did not show any protection of rat cerebellar neurons against BoNT/A intoxication by 7.
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Affiliation(s)
- Peter Šilhár
- Department of Chemistry, Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037, USA
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34
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Salzameda NT, Eubanks LM, Zakhari JS, Tsuchikama K, DeNunzio NJ, Allen KN, Hixon MS, Janda KD. A cross-over inhibitor of the botulinum neurotoxin light chain B: a natural product implicating an exosite mechanism of action. Chem Commun (Camb) 2011; 47:1713-5. [PMID: 21203627 DOI: 10.1039/c0cc04078a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Clostridium botulinum produces the most lethal toxins known to man, as such they are high risk terrorist threats, and alarmingly there is no approved therapeutic. We report the first cross-over small molecule inhibitor of these neurotoxins and propose a mechanism by which it may impart its inhibitory activity.
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Affiliation(s)
- Nicholas T Salzameda
- Department of Chemistry, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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35
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Cardinale SC, Butler MM, Ruthel G, Nuss JE, Wanner LM, Li B, Pai R, Peet NP, Bavari S, Bowlin TL. Novel Benzimidazole Inhibitors of Botulinum Neurotoxin/A Display Enzyme and Cell-Based Potency. ACTA ACUST UNITED AC 2011. [PMID: 23205055 DOI: 10.1504/tbj.2011.041813] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Botulinum Neurotoxins (BoNTs) are used therapeutically and in cosmetics, providing potential for bioterrorist activity, thus driving the search for small-molecule BoNT inhibitors. This report describes a 70,000-compound screen for inhibition of BoNT/A using a FRET assay to detect proteolysis of a peptide substrate. Hits were confirmed, followed by evaluation to determine compound specificity. Inhibitors fell into three main chemical classes, and on the basis of potency and specificity of inhibition, the activities of two chemotypes were examined further. Compounds exhibited specificity for BoNT/A LC inhibition with respect to other metalloproteases and displayed activity in a neuronal assay for botulinum intoxication.
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36
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Li B, Peet NP, Butler MM, Burnett JC, Moir DT, Bowlin TL. Small molecule inhibitors as countermeasures for botulinum neurotoxin intoxication. Molecules 2010; 16:202-20. [PMID: 21193845 PMCID: PMC6259422 DOI: 10.3390/molecules16010202] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 12/20/2010] [Accepted: 12/29/2010] [Indexed: 11/18/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the most potent of known toxins and are listed as category A biothreat agents by the U.S. CDC. The BoNT-mediated proteolysis of SNARE proteins inhibits the exocytosis of acetylcholine into neuromuscular junctions, leading to life-threatening flaccid paralysis. Currently, the only therapy for BoNT intoxication (which results in the disease state botulism) includes experimental preventative antibodies and long-term supportive care. Therefore, there is an urgent need to identify and develop inhibitors that will serve as both prophylactic agents and post-exposure ‘rescue’ therapeutics. This review focuses on recent progress to discover and develop small molecule inhibitors as therapeutic countermeasures for BoNT intoxication.
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Affiliation(s)
- Bing Li
- Microbiotix, Inc., One Innovation Drive, Worcester, MA 01605, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-508-757-2800; Fax: +1-508-757-1999
| | - Norton P. Peet
- Microbiotix, Inc., One Innovation Drive, Worcester, MA 01605, USA
| | | | - James C. Burnett
- Target, Structure-Based Drug Discovery Group, SAIC-Frederick, Inc., National Cancer Institute at Frederick, 1050 Boyles Street, Frederick, MD 21702, USA; E-Mail: (J.C.B.)
| | - Donald T. Moir
- Microbiotix, Inc., One Innovation Drive, Worcester, MA 01605, USA
| | - Terry L. Bowlin
- Microbiotix, Inc., One Innovation Drive, Worcester, MA 01605, USA
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37
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Mayorov AV, Willis B, Di Mola A, Adler D, Borgia J, Jackson O, Wang J, Luo Y, Tang L, Knapp RJ, Natarajan C, Goodnough MC, Zilberberg N, Simpson LL, Janda KD. Symptomatic relief of botulinum neurotoxin/a intoxication with aminopyridines: a new twist on an old molecule. ACS Chem Biol 2010; 5:1183-91. [PMID: 20936877 DOI: 10.1021/cb1002366] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Botulinum neurotoxins (BoNT) are the etiological agents responsible for botulism, a disease characterized by peripheral neuromuscular blockade and a characteristic flaccid paralysis of humans. BoNT/A is the most toxic protein known to man and has been classified by the Centers of Disease Control (CDC) as one of the six highest-risk threat agents for bioterrorism. Of particular concern is the apparent lack of clinical interventions that can reverse cellular intoxication. Efforts to uncover molecules that can act within an intoxicated cell so as to provide symptomatic relief to BoNT/A are paramount. Aminopyridines have shown clinical efficacy for multiple sclerosis treatment as well as BoNT/A intoxication; yet, aminopyridines for BoNT/A treatment has been abandoned because of blood brain barrier (BBB) penetration producing undesired neurotoxic side effects. Two aminopyridines (5 and 11) exhibited inhibitory activity toward Shaker-IR voltage-gated potassium (K(V)1.x) channels with potencies similar to that of the previous "gold-standard", 3,4-diaminopyridine (3,4-DAP), including reversal of symptoms from BoNT-induced paralysis in phrenic nerve-hemidiaphragm preparations. Importantly, pharmacokinetic experiments revealed a lack of BBB penetration of 5, which is a significant advancement toward resolving the neurotoxicity issues associated with prolonged 3,4-DAP treatments. Finally, 5 was found to be as effective as 3,4-DAP in rescuing BoNT-poisoned mice in the mouse lethality assay, signifying an optimized balance between the undesired permeability across the BBB and the required permeability across lipid cellular membranes. The results demonstrate that 5 is the most promising small molecule K(+) channel inhibitor discovered to date for the treatment of BoNT/A intoxication.
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Affiliation(s)
- Alexander V. Mayorov
- Departments of Chemistry and Immunology, Skaggs Institute for Chemical Biology and Worm Institute of Research & Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Bert Willis
- Departments of Chemistry and Immunology, Skaggs Institute for Chemical Biology and Worm Institute of Research & Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Antonia Di Mola
- Departments of Chemistry and Immunology, Skaggs Institute for Chemical Biology and Worm Institute of Research & Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Derek Adler
- Sanofi-Aventis, Discovery Metabolism and Pharmacokinetics Safety Department, Bridgewater, New Jersey 08807, United States
| | - Jennifer Borgia
- Sanofi-Aventis, Discovery Metabolism and Pharmacokinetics Safety Department, Bridgewater, New Jersey 08807, United States
| | - Olin Jackson
- Sanofi-Aventis, Discovery Metabolism and Pharmacokinetics Safety Department, Bridgewater, New Jersey 08807, United States
| | - Jie Wang
- Sanofi-Aventis, Discovery Metabolism and Pharmacokinetics Safety Department, Bridgewater, New Jersey 08807, United States
| | - Yongyi Luo
- Sanofi-Aventis, Discovery Metabolism and Pharmacokinetics Safety Department, Bridgewater, New Jersey 08807, United States
| | - Lei Tang
- Sanofi-Aventis, Discovery Metabolism and Pharmacokinetics Safety Department, Bridgewater, New Jersey 08807, United States
| | - Richard J. Knapp
- Sanofi-Aventis, Discovery Metabolism and Pharmacokinetics Safety Department, Bridgewater, New Jersey 08807, United States
| | - Chandra Natarajan
- Sanofi-Aventis, Discovery Metabolism and Pharmacokinetics Safety Department, Bridgewater, New Jersey 08807, United States
| | | | - Noam Zilberberg
- Department of Life Sciences, Ben Gurion University, Beer Sheva 84105, Israel
| | - Lance L. Simpson
- Department of Medicine Jefferson Medical College, Thomas Jefferson University, 1020 Locust St, Rm 314-JAH, Philadelphia, Pennsylvania 19107, United States
| | - Kim D. Janda
- Departments of Chemistry and Immunology, Skaggs Institute for Chemical Biology and Worm Institute of Research & Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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38
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Ramasamy S, Liu CQ, Tran H, Gubala A, Gauci P, McAllister J, Vo T. Principles of antidote pharmacology: an update on prophylaxis, post-exposure treatment recommendations and research initiatives for biological agents. Br J Pharmacol 2010; 161:721-48. [PMID: 20860656 DOI: 10.1111/j.1476-5381.2010.00939.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The use of biological agents has generally been confined to military-led conflicts. However, there has been an increase in non-state-based terrorism, including the use of asymmetric warfare, such as biological agents in the past few decades. Thus, it is becoming increasingly important to consider strategies for preventing and preparing for attacks by insurgents, such as the development of pre- and post-exposure medical countermeasures. There are a wide range of prophylactics and treatments being investigated to combat the effects of biological agents. These include antibiotics (for both conventional and unconventional use), antibodies, anti-virals, immunomodulators, nucleic acids (analogues, antisense, ribozymes and DNAzymes), bacteriophage therapy and micro-encapsulation. While vaccines are commercially available for the prevention of anthrax, cholera, plague, Q fever and smallpox, there are no licensed vaccines available for use in the case of botulinum toxins, viral encephalitis, melioidosis or ricin. Antibiotics are still recommended as the mainstay treatment following exposure to anthrax, plague, Q fever and melioidosis. Anti-toxin therapy and anti-virals may be used in the case of botulinum toxins or smallpox respectively. However, supportive care is the only, or mainstay, post-exposure treatment for cholera, viral encephalitis and ricin - a recommendation that has not changed in decades. Indeed, with the difficulty that antibiotic resistance poses, the development and further evaluation of techniques and atypical pharmaceuticals are fundamental to the development of prophylaxis and post-exposure treatment options. The aim of this review is to present an update on prophylaxis and post-exposure treatment recommendations and research initiatives for biological agents in the open literature from 2007 to 2009.
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Affiliation(s)
- S Ramasamy
- Defence Science & Technology Organisation, Human Protection and Performance Division, Fishermans Bend, Vic., Australia.
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39
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Zhang Y, Gao X, Qin L, Buchko GW, Robinson H, Varnum SM. High-level expression, purification, crystallization and preliminary X-ray crystallographic studies of the receptor-binding domain of botulinum neurotoxin serotype D. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1610-3. [PMID: 21139207 DOI: 10.1107/s1744309110039874] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Accepted: 10/06/2010] [Indexed: 11/10/2022]
Abstract
Botulinum neurotoxins (BoNTs) are highly toxic proteins for humans and animals that are responsible for the deadly neuroparalytic disease botulism. Here, details of the expression and purification of the receptor-binding domain (HCR) of BoNT/D in Escherichia coli are presented. Using a codon-optimized cDNA, BoNT/D_HCR was expressed at a high level (150-200 mg per litre of culture) in the soluble fraction. Following a three-step purification protocol, very pure (>98%) BoNT/D_HCR was obtained. The recombinant BoNT/D_HCR was crystallized and the crystals diffracted to 1.65 Å resolution. The crystals belonged to space group P2(1)2(1)2(1), with unit-cell parameters a=60.8, b=89.7, c=93.9 Å. Preliminary crystallographic data analysis revealed the presence of one molecule in the asymmetric unit.
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Affiliation(s)
- Yanfeng Zhang
- Cell Biology and Biochemistry Group, Pacific Northwest National Laboratory, Richland, WA 99352, USA
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40
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Nuss JE, Dong Y, Wanner LM, Ruthel G, Wipf P, Gussio R, Vennerstrom JL, Bavari S, Burnett JC. Pharmacophore Refinement Guides the Rational Design of Nanomolar-Range Inhibitors of the Botulinum Neurotoxin Serotype A Metalloprotease. ACS Med Chem Lett 2010; 1:301-305. [PMID: 21116458 DOI: 10.1021/ml100056v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the deadliest of microbial toxins. The enzymes' Zinc(II) metalloprotease, referred to as the light chain (LC) component, inhibits acetylcholine release into neuromuscular junctions, resulting in the disease botulism. Currently, no therapies counter BoNT poisoning post-neuronal intoxication; however, it is hypothesized that small molecules may be used to inhibit BoNT LC activity in the neuronal cytosol. Herein, we describe the pharmacophore-based design and chemical synthesis of potent (non-Zinc(II) chelating) small molecule (non-peptidic) inhibitors (SMNPIs) of the BoNT serotype A LC (the most toxic of the BoNT serotype LCs). Specifically, the three-dimensional superimpositions of 2-[4-(4-amidinephenoxy)-phenyl]-indole-6-amidine-based SMNPI regioisomers (K(i) = 0.600 μM (± 0.100 μM)), with a novel lead bis-[3-amide-5-(imidazolino)-phenyl]-terephthalamide (BAIPT)-based SMNPI (K(i) = 8.52 μM (± 0.53 μM)), resulted in a refined 4-zone pharmacophore. The refined model guided the design of BAIPT-based SMNPIs possessing K(i) values = 0.572 μM (± 0.041 μM) and 0.900 μM (± 0.078 μM).
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Affiliation(s)
- Jonathan E. Nuss
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702
| | - Yuxiang Dong
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Laura M. Wanner
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702
| | - Gordon Ruthel
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702
| | - Peter Wipf
- Department of Chemistry and Combinatorial Chemistry Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Rick Gussio
- Developmental Therapeutics Program, National Cancer Institute at Frederick, Frederick, Maryland 21702
| | - Jonathan L. Vennerstrom
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702
| | - James C. Burnett
- Target Structure-Based Drug Discovery Group, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, Maryland 21702
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41
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Zuniga JE, Hammill JT, Drory O, Nuss JE, Burnett JC, Gussio R, Wipf P, Bavari S, Brunger AT. Iterative structure-based peptide-like inhibitor design against the botulinum neurotoxin serotype A. PLoS One 2010; 5:e11378. [PMID: 20614028 PMCID: PMC2894858 DOI: 10.1371/journal.pone.0011378] [Citation(s) in RCA: 22] [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: 04/27/2010] [Accepted: 06/08/2010] [Indexed: 11/26/2022] Open
Abstract
The botulinum neurotoxin serotype A light chain (BoNT/A LC) protease is the catalytic component responsible for the neuroparalysis that is characteristic of the disease state botulism. Three related peptide-like molecules (PLMs) were designed using previous information from co-crystal structures, synthesized, and assayed for in vitro inhibition against BoNT/A LC. Our results indicate these PLMS are competitive inhibitors of the BoNT/A LC protease and their Ki values are in the nM-range. A co-crystal structure for one of these inhibitors was determined and reveals that the PLM, in accord with the goals of our design strategy, simultaneously involves both ionic interactions via its P1 residue and hydrophobic contacts by means of an aromatic group in the P2′ position. The PLM adopts a helical conformation similar to previously determined co-crystal structures of PLMs, although there are also major differences to these other structures such as contacts with specific BoNT/A LC residues. Our structure further demonstrates the remarkable plasticity of the substrate binding cleft of the BoNT/A LC protease and provides a paradigm for iterative structure-based design and development of BoNT/A LC inhibitors.
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Affiliation(s)
- Jorge E. Zuniga
- Howard Hughes Medical Institute and Departments of Molecular and Cellular Physiology, Neurology and Neurological Science, Structural Biology, and Photon Science, Stanford University, Stanford, California, United States of America
| | - Jared T. Hammill
- Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Omri Drory
- Howard Hughes Medical Institute and Departments of Molecular and Cellular Physiology, Neurology and Neurological Science, Structural Biology, and Photon Science, Stanford University, Stanford, California, United States of America
| | - Jonathan E. Nuss
- Division of Bacteriology, Department of Immunology, Target Identification, and Translational Research, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - James C. Burnett
- Target Structure-Based Drug Discovery Group, National Cancer Institute at Frederick, Frederick, Maryland, United States of America
| | - Rick Gussio
- Information Technology Branch, Developmental Therapeutics Program, National Cancer Institute at Frederick, Frederick, Maryland, United States of America
| | - Peter Wipf
- Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (PW); (ATB)
| | - Sina Bavari
- Division of Bacteriology, Department of Immunology, Target Identification, and Translational Research, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Axel T. Brunger
- Howard Hughes Medical Institute and Departments of Molecular and Cellular Physiology, Neurology and Neurological Science, Structural Biology, and Photon Science, Stanford University, Stanford, California, United States of America
- * E-mail: (PW); (ATB)
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42
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Eubanks LM, Šilhár P, Salzameda NT, Zakhari JS, Xiaochuan F, Barbieri JT, Shoemaker CB, Hixon MS, Janda KD. Identification of a Natural Product Antagonist against the Botulinum Neurotoxin Light Chain Protease. ACS Med Chem Lett 2010; 1:268-272. [PMID: 20959871 DOI: 10.1021/ml100074s] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the etiological agents responsible for botulism, a disease characterized by peripheral neuromuscular blockade and a characteristic flaccid paralysis of humans. BoNTs are the most lethal known poisons affecting humans and has been recognized as a potential bioterrorist threat. Current treatments for botulinum poisoning are predominately prophylactic in nature relying on passive immunization with antitoxins. Inhibition of the BoNT light chain metalloprotease (LC) has emerged as a new therapeutic strategy for the treatment of botulism that may provide an effective post-exposure remedy. A high-throughput screening effort against the light chain of BoNT serotype A (LC/A) was conducted with the John Hopkins Clinical Compound Library comprised of over 1,500 existing drugs. Lomofungin, a natural product first isolated in the late 1960's, was identified as an inhibitor of LC/A, displaying classical noncompetitive inhibition kinetics with a K(i) of 6.7 ± 0.7 µM. Inhibitor combination studies reveal that lomofungin binding is nonmutually exclusive (synergistic). The inhibition profile of lomofungin has been delineated by the use of both an active site inhibitor, 2,4-dichlorocinnamic hydroxamate, and a noncompetitive inhibitor d-chicoric acid; the mechanistic implications of these observations are discussed. Lastly, cellular efficacy was investigated using a rat primary cell model which demonstrated that lomofungin can protect against SNAP-25 cleavage, the intracellular protein target of LC/A.
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Affiliation(s)
- Lisa M. Eubanks
- Departments of Chemistry and Immunology
- The Skaggs Institute for Chemical Biology
- The Worm Institute for Research and Medicine
| | - Peter Šilhár
- Departments of Chemistry and Immunology
- The Skaggs Institute for Chemical Biology
| | | | - Joseph S. Zakhari
- Departments of Chemistry and Immunology
- The Skaggs Institute for Chemical Biology
| | - Feng Xiaochuan
- Department of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, Massachusetts 01536
| | - Joseph T. Barbieri
- Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226
| | - Charles B. Shoemaker
- Department of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, Massachusetts 01536
| | - Mark S. Hixon
- Departments of Chemistry and Immunology
- The Skaggs Institute for Chemical Biology
- The Worm Institute for Research and Medicine
| | - Kim D. Janda
- Departments of Chemistry and Immunology
- The Skaggs Institute for Chemical Biology
- The Worm Institute for Research and Medicine
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43
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Saunders MJ, Graves SW, Sklar LA, Oprea TI, Edwards BS. High-throughput multiplex flow cytometry screening for botulinum neurotoxin type a light chain protease inhibitors. Assay Drug Dev Technol 2010; 8:37-46. [PMID: 20035615 DOI: 10.1089/adt.2009.0219] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Given their medical importance, proteases have been studied by diverse approaches and screened for small molecule protease inhibitors. Here, we present a multiplexed microsphere-based protease assay that uses high-throughput flow cytometry to screen for inhibitors of the light chain protease of botulinum neurotoxin type A (BoNTALC). Our assay uses a full-length substrate and several deletion mutants screened in parallel to identify small molecule inhibitors. The use of multiplex flow cytometry has the advantage of using full-length substrates, which contain already identified distal-binding elements for the BoNTALC, and could lead to a new class of BoNTALC inhibitors. In this study, we have screened 880 off patent drugs and bioavailable compounds to identify ebselen as an in vitro inhibitor of BoNTALC. This discovery demonstrates the validity of our microsphere-based approach and illustrates its potential for high-throughput screening for inhibitors of proteases in general.
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Affiliation(s)
- Matthew J Saunders
- The Center for Molecular Discovery and Department of Pathology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
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44
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Hakami RM, Ruthel G, Stahl AM, Bavari S. Gaining ground: assays for therapeutics against botulinum neurotoxin. Trends Microbiol 2010; 18:164-72. [DOI: 10.1016/j.tim.2010.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 01/20/2010] [Accepted: 02/01/2010] [Indexed: 11/15/2022]
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45
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Li B, Pai R, Cardinale SC, Butler MM, Peet NP, Moir DT, Bavari S, Bowlin TL. Synthesis and biological evaluation of botulinum neurotoxin a protease inhibitors. J Med Chem 2010; 53:2264-76. [PMID: 20155918 DOI: 10.1021/jm901852f] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
NSC 240898 was previously identified as a botulinum neurotoxin A light chain (BoNT/A LC) endopeptidase inhibitor by screening the National Cancer Institute Open Repository diversity set. Two types of analogues have been synthesized and shown to inhibit BoNT/A LC in a FRET-based enzyme assay, with confirmation in an HPLC-based assay. These two series of compounds have also been evaluated for inhibition of anthrax lethal factor (LF), an unrelated metalloprotease, to examine enzyme specificity of the BoNT/A LC inhibition. The most potent inhibitor against BoNT/A LC in these two series is compound 12 (IC(50) = 2.5 microM, FRET assay), which is 4.4-fold more potent than the lead structure and 11.2-fold more selective for BoNT/A LC versus the anthrax LF metalloproteinase. Structure-activity relationship studies have revealed structural features important to potency and enzyme specificity.
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Affiliation(s)
- Bing Li
- Microbiotix Inc, One Innovation Drive, Worcester, Massachusetts 01605, USA.
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46
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Burnett JC, Li B, Pai R, Cardinale SC, Butler MM, Peet NP, Moir D, Bavari S, Bowlin T. Analysis of Botulinum Neurotoxin Serotype A Metalloprotease Inhibitors: Analogs of a Chemotype for Therapeutic Development in the Context of a Three-Zone Pharmacophore. OPEN ACCESS BIOINFORMATICS 2010; 2010:11-18. [PMID: 21103387 PMCID: PMC2983112 DOI: 10.2147/oab.s7251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Botulinum neurotoxins (BoNTs), and in particular serotype A, are the most poisonous of known biological substances, and are responsible for the flaccid paralysis of the disease state botulism. Because of the extreme toxicity of these enzymes, BoNTs are considered highest priority biothreat agents. To counter BoNT serotype A (BoNT/A) poisoning, the discovery and development of small molecule, drug-like inhibitors as post-intoxication therapeutic agents has been/is being pursued. Specifically, we are focusing on inhibitors of the BoNT/A light chain (LC) (ie, a metalloprotease) subunit, since such compounds can enter neurons and provide post-intoxication protection of the enzyme target substrate. To aid/facilitate this drug development effort, a pharmacophore for inhibition of the BoNT/A LC subunit was previously developed, and is continually being refined via the incorporation of novel and diverse inhibitor chemotypes. Here, we describe several analogs of a promising therapeutic chemotype in the context of the pharmacophore for BoNT/A LC inhibition. Specifically, we describe: 1) the pharmacophoric 'fits' of the analogs and how these 'fits' rationalize the in vitro inhibitory potencies of the analogs and 2) pharmacophore refinement via the inclusion of new components from the most potent of the presented analogs.
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Affiliation(s)
- James C. Burnett
- Target, Structure-Based Drug Discovery Group, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, MD 21702 (USA)
| | - Bing Li
- Microbiotix, Inc., Worcester, MA 01605 (USA)
| | - Ramdas Pai
- Microbiotix, Inc., Worcester, MA 01605 (USA)
| | | | | | | | - Donald Moir
- Microbiotix, Inc., Worcester, MA 01605 (USA)
| | - Sina Bavari
- Division of Integrated Toxicology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702 (USA)
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47
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Šilhár P, Čapková K, Salzameda NT, Barbieri JT, Hixon MS, Janda KD. Botulinum neurotoxin A protease: discovery of natural product exosite inhibitors. J Am Chem Soc 2010; 132:2868-9. [PMID: 20158239 PMCID: PMC2832098 DOI: 10.1021/ja910761y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new mechanistic class of BoNT/A zinc metalloprotease inhibitors, from Echinacea, exemplified by the natural product d-chicoric acid (I1) is disclosed. A detailed evaluation of chicoric acid's mechanism of inhibition reveals that the inhibitor binds to an exosite, displays noncompetitive partial inhibition, and is synergistic with a competitive active site inhibitor when used in combination. Other components found in Echinacea, I3 and I4, were also inhibitors of the protease.
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Affiliation(s)
- Peter Šilhár
- Departments of Chemistry and Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Kateřina Čapková
- Departments of Chemistry and Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Nicholas T. Salzameda
- Departments of Chemistry and Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Joseph T. Barbieri
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226
| | - Mark S. Hixon
- Discovery Biology, Takeda San Diego, Inc., San Diego CA, 10410 Science Center Dr, San Diego, CA 92121, USA
| | - Kim D. Janda
- Departments of Chemistry and Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
- Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute,10550 North Torrey Pines Rd, La Jolla, CA 92037
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48
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Stenmark P, Dong M, Dupuy J, Chapman ER, Stevens RC. Crystal structure of the botulinum neurotoxin type G binding domain: insight into cell surface binding. J Mol Biol 2010; 397:1287-97. [PMID: 20219474 DOI: 10.1016/j.jmb.2010.02.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/22/2010] [Accepted: 02/23/2010] [Indexed: 10/19/2022]
Abstract
Botulinum neurotoxins (BoNTs) typically bind the neuronal cell surface via dual interactions with both protein receptors and gangliosides. We present here the 1.9-A X-ray structure of the BoNT serotype G (BoNT/G) receptor binding domain (residues 868-1297) and a detailed view of protein receptor and ganglioside binding regions. The ganglioside binding motif (SxWY) has a conserved structure compared to the corresponding regions in BoNT serotype A and BoNT serotype B (BoNT/B), but several features of interactions with the hydrophilic face of the ganglioside are absent at the opposite side of the motif in the BoNT/G ganglioside binding cleft. This may significantly reduce the affinity between BoNT/G and gangliosides. BoNT/G and BoNT/B share the protein receptor synaptotagmin (Syt) I/II. The Syt binding site has a conserved hydrophobic plateau located centrally in the proposed protein receptor binding interface (Tyr1189, Phe1202, Ala1204, Pro1205, and Phe1212). Interestingly, only 5 of 14 residues that are important for binding between Syt-II and BoNT/B are conserved in BoNT/G, suggesting that the means by which BoNT/G and BoNT/B bind Syt diverges more than previously appreciated. Indeed, substitution of Syt-II Phe47 and Phe55 with alanine residues had little effect on the binding of BoNT/G, but strongly reduced the binding of BoNT/B. Furthermore, an extended solvent-exposed hydrophobic loop, located between the Syt binding site and the ganglioside binding cleft, may serve as a third membrane association and binding element to contribute to high-affinity binding to the neuronal membrane. While BoNT/G and BoNT/B are homologous to each other and both utilize Syt-I/Syt-II as their protein receptor, the precise means by which these two toxin serotypes bind to Syt appears surprisingly divergent.
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Affiliation(s)
- Pål Stenmark
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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49
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Nakai Y, Pellett S, Tepp WH, Johnson EA, Janda KD. Toosendanin: synthesis of the AB-ring and investigations of its anti-botulinum properties (Part II). Bioorg Med Chem 2009; 18:1280-7. [PMID: 20044261 DOI: 10.1016/j.bmc.2009.12.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 12/04/2009] [Accepted: 12/08/2009] [Indexed: 10/20/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the etiological agents responsible for botulism, a disease characterized by peripheral neuromuscular blockade and a characteristic flaccid paralysis of humans. The natural product toosendanin, a limonoid, is a traditional Chinese medicine that has reported anti-botulinum properties in animal models. Toosendanin effectively inhibits the biological activity of BoNT/A in neuronal cells at concentrations of 200 nM, and partial inhibition can be observed with concentrations as low as 8 nM. Mechanistically, toosendanin's inhibition is due to prevention of transduction of the BoNT LC through the HC channel. Intriguing questions as to the molecular architecture of toosendanin as related to its anti-botulinum properties have focused our attention on a synthesis of toosendanin's unusual AB-ring, containing a unique bridged hemi-acetal. Within the current work, a synthetic strategy allowing access to the AB-fragment of toosendanin was achieved from a trans-decalin system. In addition, this fragment was examined for its modulation of BoNT/A intoxication in a rat spinal cord cellular assay.
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Affiliation(s)
- Yuya Nakai
- Departments of Chemistry and Immunology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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50
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Shi X, Curran JE, Liao Z, Gordon RK. The biological activity of ubiquitinated BoNT/B light chain in vitro and in human SHSY-5Y neuronal cells. J Cell Biochem 2009; 108:660-7. [PMID: 19681043 DOI: 10.1002/jcb.22300] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BoNT/B light chain is a zinc-dependent endopeptidase. After entering its target, the neuronal cell, BoNT/B is responsible for synaptobrevin-2 (VAMP-2) cleavage. This results in reduced neurotransmitter (acetylcholine) release from synaptic vesicles, yielding muscular paralysis. Since the toxin persists in neuronal cells for an extended period, regeneration of VAMP-2 is prevented. We evaluated therapeutic targets to overcome botulinum persistence because early removal would rescue the neuronal cell. The ubiquitination/proteasome cellular pathway is responsible for removing "old" or undesirable proteins. Therefore, we assessed ubiquitination of BoNT/B light chain in vitro, and characterized the effects of ubiquitination modulating drugs, PMA (phorbol 12-myristate 13-acetate) and expoxomicin, on ubiquitination of BoNT/B light chain in neuronal cells. Both drugs altered BoNT/B light chain ubiquitination. Ubiquitination in vitro and in cells decreased the biological activity of BoNT/B light chain. These results further elucidate BoNT protein degradation pathways in intoxicated neuronal cells and mechanisms to enhance toxin removal.
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Affiliation(s)
- Xuerong Shi
- Department of Regulated Laboratories, Division of Regulated Activities, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910-7500, USA.
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