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Xu H, Ge H, Shan X, Cai Z. Alteration of myoepithelial cells during botulinum toxin type A-inhibited salivary secretion. Oral Dis 2024; 30:1163-1172. [PMID: 36971615 DOI: 10.1111/odi.14576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 03/15/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023]
Abstract
OBJECTIVE Intraglandular injection of botulinum toxin type A (BoNT/A) effectively treats sialorrhea. Myoepithelial cells (MECs) are essential for salivary secretion. The role of MECs in BoNT/A-inhibited salivary secretion, and its underlying mechanisms remain unknown. MATERIALS AND METHODS BoNT/A was injected into rat submandibular glands (SMGs). At 1, 2, 4, 8, and 12 weeks postinjection, salivary flow rate of SMGs was measured. Electron microscopy, immunohistochemistry, immunofluorescence, and Western blot analysis were used to detect morphological and functional changes in MECs and chemical denervation in SMGs. RESULTS BoNT/A temporarily decreased salivary secretion in rat SMGs and this inhibitory effect lasted 4 weeks. During the inhibitory period, MECs atrophied and expressed reduced α-smooth muscle actin (α-SMA), vimentin, and phosphorylated myosin light chain 2 (p-MLC2), suggesting that BoNT/A attenuated MEC contractility. Furthermore, BoNT/A cleaved synaptosome-associated protein 25 (SNAP-25) and decreased the expression and activity of acetylcholinesterase (AChE), indicating that BoNT/A-induced chemical parasympathetic denervation of SMGs by cleaving SNAP-25. CONCLUSIONS BoNT/A temporarily caused MEC atrophy and decreased MEC contractility in rat SMGs, which contributed to reversible inhibition of salivary secretion. The underlying mechanisms involved temporary parasympathetic denervation caused by SNAP-25 cleavage. These findings provide new insights into the mechanisms of BoNT/A-inhibited salivary secretion.
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Affiliation(s)
- Hui Xu
- Department of Wangfujing General Dentistry, Beijing Stomatological Hospital, Capital Medical University, Beijing, China
| | - Huabing Ge
- Department of Wangfujing General Dentistry, Beijing Stomatological Hospital, Capital Medical University, Beijing, China
| | - Xiaofeng Shan
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
| | - Zhigang Cai
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
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Mousavi Ghahfarrokhi SS, Mahdigholi FS, Amin M. Collateral beauty in the damages: an overview of cosmetics and therapeutic applications of microbial proteases. Arch Microbiol 2023; 205:375. [PMID: 37935975 DOI: 10.1007/s00203-023-03713-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/14/2023] [Accepted: 10/16/2023] [Indexed: 11/09/2023]
Abstract
Microbial proteases are enzymes secreted by a variety of microorganisms, including bacteria and fungi, and have attracted significant attention due to their versatile applications in the food and pharmaceutical industries. In addition, certain proteases have been used in the development of skin health products and cosmetics. This article provides a review of microbial proteases in terms of their classification, sources, properties, and applications. Moreover, different pharmacological and molecular investigations have been reviewed. Various biological activities of microbial proteases, such as Arazyme, collagenase, elastin, and Nattokinase, which are involved in the digestion of dietary proteins, as well as their potential anti-inflammatory, anti-cancer, antithrombotic, and immunomodulatory effects have been included. Furthermore, their ability to control infections and treat various disorders has been discussed. Finally, this review highlights the potential applications and future perspectives of microbial proteases in biotechnology and biomedicine, and proposes further studies to develop new perspectives for disease control and health-promoting strategies using microbial resources.
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Affiliation(s)
- Seyed Sadeq Mousavi Ghahfarrokhi
- Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
- Pharmaceutical Microbiology Group, Pharmaceutical Quality Assurance Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran
- Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Fateme Sadat Mahdigholi
- Department of Biomaterials, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohsen Amin
- Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
- Pharmaceutical Microbiology Group, Pharmaceutical Quality Assurance Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.
- Room No. 1-221, Faculty of Pharmacy, 16th Azar Street, Tehran University of Medical Sciences, Tehran, Iran.
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A Pilot Study of A2NTX, a Novel Low-Molecular-Weight Neurotoxin Derived from Subtype A2 for Post-Stroke Lower Limb Spasticity: Comparison with OnabotulinumtoxinA. Toxins (Basel) 2022; 14:toxins14110739. [PMID: 36355989 PMCID: PMC9697926 DOI: 10.3390/toxins14110739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/15/2022] [Accepted: 10/20/2022] [Indexed: 01/26/2023] Open
Abstract
All the currently used type A botulinum neurotoxins for clinical uses are of subtype A1. We compared the efficacy and safety for the first time head-to-head between a novel botulinum toxin A2NTX prepared from subtype A2 and onabotulinumtoxinA (BOTOX) derived from A1 for post-stroke spasticity. We assessed the modified Ashworth scale (MAS) of the ankle joint, the mobility scores of Functional Independence Measure (FIM), and the grip power of the unaffected hand before and after injecting 300 units of BOTOX or A2NTX into calf muscles. The procedure was done in a blinded manner for the patient, the injecting physician, and the examiner. Stroke patients with chronic spastic hemiparesis (15 for A2NTX and 16 for BOTOX) were enrolled, and 11 for A2NTX and 13 for BOTOX (MAS of ankle; > or = 2) were entered for the MAS study. Area-under-curves of changes in MAS (primary outcome) were greater for A2NTX by day 30 (p = 0.044), and were similar by day 60. FIM was significantly improved in the A2NTX group (p = 0.005), but not in the BOTOX group by day 60. The hand grip of the unaffected limb was significantly decreased in the BOTOX-injected group (p = 0.002), but was unaffected in the A2NTX-injected group by day 60, suggesting there was less spread of A2NTX to the upper limb than there was with BOTOX. Being a small-sized pilot investigation with an imbalance in the gender of the subjects, the present study suggested superior efficacy and safety of A2NTX, and warrants a larger scale clinical trial of A2NTX to confirm these preliminary results.
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Go EJ, Ji J, Kim YH, Berta T, Park CK. Transient Receptor Potential Channels and Botulinum Neurotoxins in Chronic Pain. Front Mol Neurosci 2021; 14:772719. [PMID: 34776867 PMCID: PMC8586451 DOI: 10.3389/fnmol.2021.772719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/11/2021] [Indexed: 12/30/2022] Open
Abstract
Pain afflicts more than 1.5 billion people worldwide, with hundreds of millions suffering from unrelieved chronic pain. Despite widespread recognition of the importance of developing better interventions for the relief of chronic pain, little is known about the mechanisms underlying this condition. However, transient receptor potential (TRP) ion channels in nociceptors have been shown to be essential players in the generation and progression of pain and have attracted the attention of several pharmaceutical companies as therapeutic targets. Unfortunately, TRP channel inhibitors have failed in clinical trials, at least in part due to their thermoregulatory function. Botulinum neurotoxins (BoNTs) have emerged as novel and safe pain therapeutics because of their regulation of exocytosis and pro-nociceptive neurotransmitters. However, it is becoming evident that BoNTs also regulate the expression and function of TRP channels, which may explain their analgesic effects. Here, we summarize the roles of TRP channels in pain, with a particular focus on TRPV1 and TRPA1, their regulation by BoNTs, and briefly discuss the use of BoNTs for the treatment of chronic pain.
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Affiliation(s)
- Eun Jin Go
- Department of Physiology, Gachon Pain Center, Gachon University College of Medicine, Incheon, South Korea
| | - Jeongkyu Ji
- Gachon University College of Medicine, Incheon, South Korea
| | - Yong Ho Kim
- Department of Physiology, Gachon Pain Center, Gachon University College of Medicine, Incheon, South Korea
| | - Temugin Berta
- Department of Anesthesiology, Pain Research Center, University of Cincinnati Medical Center, Cincinnati, OH, United States
| | - Chul-Kyu Park
- Department of Physiology, Gachon Pain Center, Gachon University College of Medicine, Incheon, South Korea
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Cai S, Kumar R, Singh BR. Clostridial Neurotoxins: Structure, Function and Implications to Other Bacterial Toxins. Microorganisms 2021; 9:2206. [PMID: 34835332 PMCID: PMC8618262 DOI: 10.3390/microorganisms9112206] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 01/20/2023] Open
Abstract
Gram-positive bacteria are ancient organisms. Many bacteria, including Gram-positive bacteria, produce toxins to manipulate the host, leading to various diseases. While the targets of Gram-positive bacterial toxins are diverse, many of those toxins use a similar mechanism to invade host cells and exert their functions. Clostridial neurotoxins produced by Clostridial tetani and Clostridial botulinum provide a classical example to illustrate the structure-function relationship of bacterial toxins. Here, we critically review the recent progress of the structure-function relationship of clostridial neurotoxins, including the diversity of the clostridial neurotoxins, the mode of actions, and the flexible structures required for the activation of toxins. The mechanism clostridial neurotoxins use for triggering their activity is shared with many other Gram-positive bacterial toxins, especially molten globule-type structures. This review also summarizes the implications of the molten globule-type flexible structures to other Gram-positive bacterial toxins. Understanding these highly dynamic flexible structures in solution and their role in the function of bacterial toxins not only fills in the missing link of the high-resolution structures from X-ray crystallography but also provides vital information for better designing antidotes against those toxins.
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Affiliation(s)
- Shuowei Cai
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, Dartmouth, MA 02747, USA
| | - Raj Kumar
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA; (R.K.); (B.R.S.)
| | - Bal Ram Singh
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA; (R.K.); (B.R.S.)
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Sen E, Kota KP, Panchal RG, Bavari S, Kiris E. Screening of a Focused Ubiquitin-Proteasome Pathway Inhibitor Library Identifies Small Molecules as Novel Modulators of Botulinum Neurotoxin Type A Toxicity. Front Pharmacol 2021; 12:763950. [PMID: 34646144 PMCID: PMC8503599 DOI: 10.3389/fphar.2021.763950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 09/14/2021] [Indexed: 01/18/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) are known as the most potent bacterial toxins, which can cause potentially deadly disease botulism. BoNT Serotype A (BoNT/A) is the most studied serotype as it is responsible for most human botulism cases, and its formulations are extensively utilized in clinics for therapeutic and cosmetic applications. BoNT/A has the longest-lasting effect in neurons compared to other serotypes, and there has been high interest in understanding how BoNT/A manages to escape protein degradation machinery in neurons for months. Recent work demonstrated that an E3 ligase, HECTD2, leads to efficient ubiquitination of the BoNT/A Light Chain (A/LC); however, the dominant activity of a deubiquitinase (DUB), VCIP135, inhibits the degradation of the enzymatic component. Another DUB, USP9X, was also identified as a potential indirect contributor to A/LC degradation. In this study, we screened a focused ubiquitin-proteasome pathway inhibitor library, including VCIP135 and USP9X inhibitors, and identified ten potential lead compounds affecting BoNT/A mediated SNAP-25 cleavage in neurons in pre-intoxication conditions. We then tested the dose-dependent effects of the compounds and their potential toxic effects in cells. A subset of the lead compounds demonstrated efficacy on the stability and ubiquitination of A/LC in cells. Three of the compounds, WP1130 (degrasyn), PR-619, and Celastrol, further demonstrated efficacy against BoNT/A holotoxin in an in vitro post-intoxication model. Excitingly, PR-619 and WP1130 are known inhibitors of VCIP135 and USP9X, respectively. Modulation of BoNT turnover in cells by small molecules can potentially lead to the development of effective countermeasures against botulism.
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Affiliation(s)
- Edanur Sen
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Krishna P. Kota
- Therapeutic Discovery Branch, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Rekha G. Panchal
- Therapeutic Discovery Branch, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Sina Bavari
- Edge BioInnovation and Healion Bio, Frederick, MD, United States
| | - Erkan Kiris
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
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Poulain B, Popoff MR. Why Are Botulinum Neurotoxin-Producing Bacteria So Diverse and Botulinum Neurotoxins So Toxic? Toxins (Basel) 2019; 11:toxins11010034. [PMID: 30641949 PMCID: PMC6357194 DOI: 10.3390/toxins11010034] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/03/2019] [Accepted: 01/09/2019] [Indexed: 12/15/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the most lethal toxins among all bacterial, animal, plant and chemical poisonous compounds. Although a great effort has been made to understand their mode of action, some questions are still open. Why, and for what benefit, have environmental bacteria that accidentally interact with their host engineered so diverse and so specific toxins targeting one of the most specialized physiological processes, the neuroexocytosis of higher organisms? The extreme potency of BoNT does not result from only one hyperactive step, but in contrast to other potent lethal toxins, from multi-step activity. The cumulative effects of the different steps, each having a limited effect, make BoNTs the most potent lethal toxins. This is a unique mode of evolution of a toxic compound, the high potency of which results from multiple steps driven by unknown selection pressure, targeting one of the most critical physiological process of higher organisms.
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Affiliation(s)
- Bernard Poulain
- Institut des Neurosciences Cellulaires et Intégratives, (INCI)-CNRS, UPR 3212 Strasbourg, France.
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Kumar R, Feltrup TM, Kukreja RV, Patel KB, Cai S, Singh BR. Evolutionary Features in the Structure and Function of Bacterial Toxins. Toxins (Basel) 2019; 11:toxins11010015. [PMID: 30609803 PMCID: PMC6356308 DOI: 10.3390/toxins11010015] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/24/2018] [Accepted: 12/25/2018] [Indexed: 12/21/2022] Open
Abstract
Toxins can function both as a harmful and therapeutic molecule, depending on their concentrations. The diversity in their function allows us to ask some very pertinent questions related to their origin and roles: (a) What makes them such effective molecules? (b) Are there evolutionary features encoded within the structures of the toxins for their function? (c) Is structural hierarchy in the toxins important for maintaining their structure and function? (d) Do protein dynamics play a role in the function of toxins? and (e) Do the evolutionary connections to these unique features and functions provide the fundamental points in driving evolution? In light of the growing evidence in structural biology, it would be appropriate to suggest that protein dynamics and flexibility play a much bigger role in the function of the toxin than the structure itself. Discovery of IDPs (intrinsically disorder proteins), multifunctionality, and the concept of native aggregation are shaking the paradigm of the requirement of a fixed three-dimensional structure for the protein’s function. Growing evidence supporting the above concepts allow us to redesign the structure-function aspects of the protein molecules. An evolutionary model is necessary and needs to be developed to study these important aspects. The criteria for a well-defined model would be: (a) diversity in structure and function, (b) unique functionality, and (c) must belong to a family to define the evolutionary relationships. All these characteristics are largely fulfilled by bacterial toxins. Bacterial toxins are diverse and widely distributed in all three forms of life (Bacteria, Archaea and Eukaryotes). Some of the unique characteristics include structural folding, sequence and functional combination of domains, targeting a cellular process to execute their function, and most importantly their flexibility and dynamics. In this work, we summarize certain unique aspects of bacterial toxins, including role of structure in defining toxin function, uniqueness in their enzymatic function, and interaction with their substrates and other proteins. Finally, we have discussed the evolutionary aspects of toxins in detail, which will help us rethink the current evolutionary theories. A careful study, and appropriate interpretations, will provide answers to several questions related to the structure-function relationship of proteins, in general. Additionally, this will also allow us to refine the current evolution theories.
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Affiliation(s)
- Raj Kumar
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA.
| | - Thomas M Feltrup
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA.
| | - Roshan V Kukreja
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA.
| | - Kruti B Patel
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA.
| | - Shuowei Cai
- Department of Chemistry and Biochemistry, University of Massachusetts, Dartmouth, MA 02747, USA.
| | - Bal Ram Singh
- Botulinum Research Center, Institute of Advanced Sciences, Dartmouth, MA 02747, USA.
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Lebeda FJ, Adler M, Dembek ZF. Yesterday and Today: The Impact of Research Conducted at Camp Detrick on Botulinum Toxin. Mil Med 2018; 183:85-95. [PMID: 29420800 DOI: 10.1093/milmed/usx047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 10/23/2017] [Indexed: 11/12/2022] Open
Abstract
Introduction This review summarizes the research conducted on botulinum toxin (BoTx) from 1943 to 1956 by a small group of Camp Detrick investigators and their staff. A systematic, cross-disciplinary approach was used to develop effective vaccines against this biological warfare threat agent. In response to the potential need for medical countermeasures against BoTx during World War II, the refinement of isolation and purification techniques for BoTx successfully led to the large-scale production of botulinum toxoid vaccines. In addition, the work at Camp Detrick provided the foundation for the subsequent use of BoTx as a tool for studying the trophic regulation of skeletal muscle within motor neuron terminals and, more recently, for elucidation of the intricate details of neurotransmitter release at the molecular level. Indirectly, Camp Detrick investigators also played a significant role in studies that culminated in the use of BoTx as a pharmaceutical product that has been approved by the U.S. Food and Drug Administration for treating movement disorders, autonomic dysfunctions, and other conditions. Methods Online literature searches were performed with Google, Google Scholar, PubMed, the bibliography from the Camp Detrick technical library, and at the Defense Technical Information Center. Reference lists in some of the primary research publications and reviews also provided source material. Search terms included botulinum, botulinus, and Camp Detrick. References related to the subsequent impacts of the Camp Detrick results were selected and cited from reviews and primary references in the more recent literature. Notes on toxin nomenclature and potential sources of error in this study are presented. Results The literature searches returned 27 citations of Camp Detrick authors, 24 of which were articles in peer-reviewed journals. The publications by these investigators included several disciplines such as biochemistry, immunology, pharmacology, physiology, and toxicology. A fundamental finding was the identification of critical nutritional components for improved growth of Clostridium botulinum and the increased production of BoTx serotype A. The purification processes that were developed at Camp Detrick allowed for the production of crystalline material to be scaled up for the manufacture of toxoid vaccine. Based on the research by Camp Detrick scientists, a toxoid supply of over 1 million units was available to vaccinate ~300,000 troops before the large-scale operations of D-Day. Conclusions BoTx research during the period 1943 to 1956 resulted in refinements in the techniques for isolating and purifying the crystalline BoTx type A. These results led to the development and manufacture of a toxoid vaccine that was available in a sufficient quantity to protect ~300,000 warfighters in a large-scale military operation. One of the most important long-term consequences derived from the knowledge gained by the efforts at Camp Detrick was the development in the 1980s of safe and effective therapeutic uses for BoTx type A, the most lethal biological substance known.
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Affiliation(s)
- Frank J Lebeda
- Systems Biology Collaboration Center, US Army Center for Environmental Health Research, 568 Doughten Drive, US Army Medical Research and Materiel Command (USAMRMC), Fort Detrick, MD 21702
| | - Michael Adler
- US Army Medical Research Institute of Chemical Defense, Medical Toxicology Division, Neuroscience Branch, 2900 Ricketts Point Road, Aberdeen Proving Ground, Edgewood Area, MD 21010
| | - Zygmunt F Dembek
- Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, 3154 Jones Bridge Road, Bethesda, MD 20814
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Fan Y, Dong J, Lou J, Wen W, Conrad F, Geren IN, Garcia-Rodriguez C, Smith TJ, Smith LA, Ho M, Pires-Alves M, Wilson BA, Marks JD. Monoclonal Antibodies that Inhibit the Proteolytic Activity of Botulinum Neurotoxin Serotype/B. Toxins (Basel) 2015; 7:3405-23. [PMID: 26343720 PMCID: PMC4591640 DOI: 10.3390/toxins7093405] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/10/2015] [Accepted: 08/18/2015] [Indexed: 12/19/2022] Open
Abstract
Existing antibodies (Abs) used to treat botulism cannot enter the cytosol of neurons and bind to botulinum neurotoxin (BoNT) at its site of action, and thus cannot reverse paralysis. However, Abs targeting the proteolytic domain of the toxin could inhibit the proteolytic activity of the toxin intracellularly and potentially reverse intoxication, if they could be delivered intracellularly. As such, antibodies that neutralize toxin activity could serve as potent inhibitory cargos for therapeutic antitoxins against botulism. BoNT serotype B (BoNT/B) contains a zinc endopeptidase light chain (LC) domain that cleaves synaoptobrevin-2, a SNARE protein responsible for vesicle fusion and acetylcholine vesicle release. To generate monoclonal Abs (mAbs) that could reverse paralysis, we targeted the protease domain for Ab generation. Single-chain variable fragment (scFv) libraries from immunized mice or humans were displayed on yeast, and 19 unique BoNT/B LC-specific mAbs isolated by fluorescence-activated cell sorting (FACS). The equilibrium dissociation constants (KD) of these mAbs for BoNT/B LC ranged from 0.24 nM to 14.3 nM (mean KD 3.27 nM). Eleven mAbs inhibited BoNT/B LC proteolytic activity. The fine epitopes of selected mAbs were identified by alanine-scanning mutagenesis, revealing that inhibitory mAbs bound near the active site, substrate-binding site or the extended substrate-binding site. The results provide mAbs that could prove useful for intracellular reversal of paralysis and identify epitopes that could be targeted by small molecules inhibitors.
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Affiliation(s)
- Yongfeng Fan
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, Room 3C-38, 1001 Potrero Avenue, San Francisco, CA 94110, USA.
| | - Jianbo Dong
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, Room 3C-38, 1001 Potrero Avenue, San Francisco, CA 94110, USA.
| | - Jianlong Lou
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, Room 3C-38, 1001 Potrero Avenue, San Francisco, CA 94110, USA.
| | - Weihua Wen
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, Room 3C-38, 1001 Potrero Avenue, San Francisco, CA 94110, USA.
| | - Fraser Conrad
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, Room 3C-38, 1001 Potrero Avenue, San Francisco, CA 94110, USA.
| | - Isin N Geren
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, Room 3C-38, 1001 Potrero Avenue, San Francisco, CA 94110, USA.
| | - Consuelo Garcia-Rodriguez
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, Room 3C-38, 1001 Potrero Avenue, San Francisco, CA 94110, USA.
| | - Theresa J Smith
- Molecular and Translational Sciences Division, United States Army Medical Institute of Infectious Diseases, Fort Detrick, MD 21702, USA.
| | - Leonard A Smith
- Medical Countermeasures Technology, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702-5011, USA.
| | - Mengfei Ho
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Melissa Pires-Alves
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Brenda A Wilson
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - James D Marks
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, Room 3C-38, 1001 Potrero Avenue, San Francisco, CA 94110, USA.
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Abstract
Life as we know it heavily relies on biological catalysis, in fact, in a very nonromantic version of it, life could be considered as a series of chemical reactions, regulated by the guarding principles of thermodynamics. In ancient times, a beating heart was a good sign of vitality, however, to me, it is actually the presence of active enzymes that counts… Though we do not usually pay attention, the history of enzymology is as old as humanity itself, and dates back to the ancient times. This paper is dedicated to these early moments of this remarkable science that touched our lives in the past and will make life a lot more efficient for humanity in the future. There was almost always a delicate, fundamentally essential relationship between mankind and the enzymes. Challenged by a very alien and hostile Nature full of predators, prehistoric men soon discovered the medicinal properties of the plants, through trial and error. In fact, they accidently discovered the enzyme inhibitors and thus, in crude terms, kindled a sparkling area of research. These plant-derivatives that acted as enzyme inhibitors helped prehistoric men in their pursuit of survival and protection from predators; in hunting and fishing… Later in history, while the underlying purposes of survival and increasing the quality of life stayed intact, the ways and means of enzymology experienced a massive transformation, as the 'trial and error' methodology of the ancients is now replaced with rational scientific theories.
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Kiris E, Burnett JC, Nuss JE, Wanner LM, Peyser BD, Du HT, Gomba GY, Kota KP, Panchal RG, Gussio R, Kane CD, Tessarollo L, Bavari S. SRC family kinase inhibitors antagonize the toxicity of multiple serotypes of botulinum neurotoxin in human embryonic stem cell-derived motor neurons. Neurotox Res 2015; 27:384-98. [PMID: 25782580 PMCID: PMC4455898 DOI: 10.1007/s12640-015-9526-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 03/05/2015] [Indexed: 02/07/2023]
Abstract
Botulinum neurotoxins (BoNTs), the causative agents of botulism, are potent inhibitors of neurotransmitter release from motor neurons. There are currently no drugs to treat BoNT intoxication after the onset of the disease symptoms. In this study, we explored how modulation of key host pathways affects the process of BoNT intoxication in human motor neurons, focusing on Src family kinase (SFK) signaling. Motor neurons derived from human embryonic stem (hES) cells were treated with a panel of SFK inhibitors and intoxicated with BoNT serotypes A, B, or E (which are responsible for >95 % of human botulism cases). Subsequently, it was found that bosutinib, dasatinib, KX2-391, PP1, PP2, Src inhibitor-1, and SU6656 significantly antagonized all three of the serotypes. Furthermore, the data indicated that the treatment of hES-derived motor neurons with multiple SFK inhibitors increased the antagonistic effect synergistically. Mechanistically, the small molecules appear to inhibit BoNTs by targeting host pathways necessary for intoxication and not by directly inhibiting the toxins' proteolytic activity. Importantly, the identified inhibitors are all well-studied with some in clinical trials while others are FDA-approved drugs. Overall, this study emphasizes the importance of targeting host neuronal pathways, rather than the toxin's enzymatic components, to antagonize multiple BoNT serotypes in motor neurons.
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Affiliation(s)
- Erkan Kiris
- Geneva Foundation, Tacoma, WA, USA
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
- Neural Development Section, Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - James C. Burnett
- Leidos Biomedical Research, Inc., Computational Drug Development Group (CDDG), NCI, Frederick, MD 21702, USA
- CDDG, Developmental Therapeutics Program, NCI, Frederick, MD 21702, USA
| | - Jonathan E. Nuss
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Laura M. Wanner
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Brian D. Peyser
- CDDG, Developmental Therapeutics Program, NCI, Frederick, MD 21702, USA
| | - Hao T. Du
- Neural Development Section, Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - Glenn Y. Gomba
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Krishna P. Kota
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Rekha G. Panchal
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Rick Gussio
- CDDG, Developmental Therapeutics Program, NCI, Frederick, MD 21702, USA
| | - Christopher D. Kane
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
- Henry M. Jackson Foundation, Bethesda, MD, USA
- DoD Biotechnology High Performance Computing Software Applications Institute (BHSAI), Telemedicine and Advanced Technology Research Center (TATRC), US Army Medical Research and Materiel Command (USAMRMC), Frederick, MD 2170, USA
| | - Lino Tessarollo
- Neural Development Section, Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - Sina Bavari
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
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Systematic discovery of molecular probes targeting multiple non-orthosteric and spatially distinct sites in the botulinum neurotoxin subtype A (BoNT/A). Mol Cell Probes 2015; 29:135-43. [PMID: 25745992 DOI: 10.1016/j.mcp.2015.02.002] [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: 08/02/2014] [Revised: 02/23/2015] [Accepted: 02/23/2015] [Indexed: 01/29/2023]
Abstract
The development of molecular probes targeting proteins has traditionally relied on labeling compounds already known to bind to the protein of interest. These known ligands bind to orthosteric or allosteric sites in their target protein as a way to control their activity. Binding pockets other than known orthosteric or allosteric sites may exist that are large enough to accommodate a ligand without significantly disrupting protein activity. Such sites may provide opportunities to discriminate between subtypes or other closely related proteins, since they are under less evolutionary pressure to be conserved. The Protein Scanning with Virtual Ligand Screening (PSVLS) approach was previously used to identify a novel inhibitor and a fluorescent probe against the catalytic site of the botulinum neurotoxin subtype A (BoNT/A). PSVLS screens compound databases against multiple sites within a target protein, and the results for all the sites probed against BoNT/A, not only the catalytic site, are available online. Here, we analyze the PSVLS data for multiple sites in order to identify molecular probes with affinity for binding pockets other than the catalytic site of BoNT/A. BoNT/A is a large protein with a light (LC) and a heavy (HC) chain that can be assayed separately. We used scintillation proximity assay (SPA) to test experimentally 5 probe candidates predicted computationally to have affinity for different non-orthosteric binding regions within the HC and LC, and one compound predicted not to have affinity for either domain. The binding profiles obtained experimentally confirmed the targeting of multiple and spatially distinct pockets within BoNT/A. Moreover, inhibition assay results indicate that some of these probes do not significantly interfere with the catalytic activity of BoNT/A.
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14
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Halliwell J, Gwenin C. A label free colorimetric assay for the detection of active botulinum neurotoxin type A by SNAP-25 conjugated colloidal gold. Toxins (Basel) 2013; 5:1381-91. [PMID: 23925142 PMCID: PMC3760041 DOI: 10.3390/toxins5081381] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 07/26/2013] [Accepted: 07/30/2013] [Indexed: 01/09/2023] Open
Abstract
Botulinum neurotoxins are one of the most potent toxins known to man. Current methods of detection involve the quantification of the toxin but do not take into account the percentage of the toxin that is active. At present the assay used for monitoring the activity of the toxin is the mouse bioassay, which is lengthy and has ethical issues due to the use of live animals. This report demonstrates a novel assay that utilises the endopeptidase activity of the toxin to detect Botulinum neurotoxin in a pharmaceutical sample. The cleaving of SNAP-25 is monitored via UV-Visible spectroscopy with a limit of detection of 373 fg/mL and has been further developed into a high throughput method using a microplate reader detecting down to 600 fg/mL of active toxin. The results show clear differences between the toxin product and the placebo, which contains the pharmaceutical excipients human serum albumin and lactose, showing that the assay detects the active form of the toxin.
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Affiliation(s)
| | - Christopher Gwenin
- Author to whom correspondence should be addressed; E-Mail: ; Tel: +44-1248-383-741; Fax: +44-1248-370-528
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15
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Detection of botulinum neurotoxin serotype A, B, and F proteolytic activity in complex matrices with picomolar to femtomolar sensitivity. Appl Environ Microbiol 2012; 78:7687-97. [PMID: 22923410 DOI: 10.1128/aem.01664-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Rapid, high-throughput assays that detect and quantify botulinum neurotoxin (BoNT) activity in diverse matrices are required for environmental, clinical, pharmaceutical, and food testing. The current standard, the mouse bioassay, is sensitive but is low in throughput and precision. In this study, we present three biochemical assays for the detection and quantification of BoNT serotype A, B, and F proteolytic activities in complex matrices that offer picomolar to femtomolar sensitivity with small assay volumes and total assay times of less than 24 h. These assays consist of magnetic beads conjugated with BoNT serotype-specific antibodies that are used to purify BoNT from complex matrices before the quantification of bound BoNT proteolytic activity using the previously described BoTest reporter substrates. The matrices tested include human serum, whole milk, carrot juice, and baby food, as well as buffers containing common pharmaceutical excipients. The limits of detection were below 1 pM for BoNT/A and BoNT/F and below 10 pM for BoNT/B in most tested matrices using 200-μl samples and as low as 10 fM for BoNT/A with an increased sample volume. Together, these data describe rapid, robust, and high-throughput assays for BoNT detection that are compatible with a wide range of matrices.
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Depolarization after resonance energy transfer (DARET): A sensitive fluorescence-based assay for botulinum neurotoxin protease activity. Anal Biochem 2011; 413:36-42. [DOI: 10.1016/j.ab.2011.01.043] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/28/2011] [Accepted: 01/29/2011] [Indexed: 01/03/2023]
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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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