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Belinskaya T, Saxena A. Low levels of endogenous cholinesterases support the choice of cows, sheep and goats for the transgenic expression of human butyrylcholinesterase in milk. Chem Biol Interact 2023; 383:110691. [PMID: 37659623 DOI: 10.1016/j.cbi.2023.110691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/14/2023] [Accepted: 08/30/2023] [Indexed: 09/04/2023]
Abstract
Butyrylcholinesterase purified from human plasma (Hu BChE) as well as recombinant (r) Hu BChE are candidate enzymes that can protect humans from toxicity of organophosphorus compounds (OPs). Domestic animals such as cows, pigs, sheep, and goats have been used for the transgenic expression of a variety of valuable therapeutic proteins. Indeed, rHu BChE was successfully expressed in the milk of transgenic goats, but the presence of any endogenous cholinesterases (ChE) in milk would interfere with the isolation of expressed rHu BChE. The aim of this study was to determine the presence of endogenous ChEs in bovine, ovine, caprine, and porcine milk to determine the suitability of these species for the production of rHu BChE. Using acetyl- and butyryl- thiocholine as substrates, ChE activity (2-4 U/mL) was detected in pig milk only. ChE activities in milk from other animals were <0.01 U/mL and could only be detected following enrichment on procainamide-Sepharose gel. Two different methods based on measuring activity in the presence of acetylcholinesterase (AChE)- or BChE- specific inhibitors were used to estimate the proportions of AChE and BChE activities in enriched milk. Monoclonal antibodies (MAbs), against fetal bovine serum AChE that recognize AChEs from ruminants only, were also used to confirm the identity of AChEs. While bovine and ovine milk contain both AChE and BChE activities, caprine and porcine milk contain predominantly BChE activity. The presence of very low ChE activity supports the choice of cows, sheep, and goats for the transgenic expression of rHu BChE in milk.
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Affiliation(s)
- Tatyana Belinskaya
- Division of Biochemistry, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, USA
| | - Ashima Saxena
- Division of Biochemistry, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, USA.
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2
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Allard JL, Shields KA, Munro T, Lua LHL. Design and production strategies for developing a recombinant butyrylcholinesterase medical countermeasure for Organophosphorus poisoning. Chem Biol Interact 2022; 363:109996. [PMID: 35654125 DOI: 10.1016/j.cbi.2022.109996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/06/2022] [Accepted: 05/24/2022] [Indexed: 11/25/2022]
Abstract
Organophosphorus nerve agents represent a serious chemical threat due to their ease of production and scale of impact. The recent use of the nerve agent Novichok has re-emphasised the need for broad-spectrum medical countermeasures (MCMs) to these agents. However, current MCMs are limited. Plasma derived human butyrylcholinesterase (huBChE) is a promising novel bioscavenger MCM strategy, but is prohibitively expensive to isolate from human plasma at scale. Efforts to produce recombinant huBChE (rBChE) in various protein expression platforms have failed to achieve key critical attributes of huBChE such as circulatory half-life. These proteins often lack critical features such as tetrameric structure and requisite post-translational modifications. This review evaluates previous attempts to generate rBChE and assesses recent advances in mammalian cell expression and protein engineering strategies that could be deployed to achieve the required half-life and yield for a viable rBChE MCM. This includes the addition of a proline-rich attachment domain, fusion proteins, post translational modifications, expression system selection and optimised downstream processes. Whilst challenges remain, a combinatorial approach of these strategies demonstrates potential as a technically feasible approach to achieving a bioactive and cost effective bioscavenger MCM.
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Affiliation(s)
- Joanne L Allard
- Defence Science and Technology Group, Fishermans Bend, Victoria, 3207, Australia; The University of Queensland, Brisbane, Queensland, 4072, Australia.
| | - Katherine A Shields
- Defence Science and Technology Group, Fishermans Bend, Victoria, 3207, Australia
| | - TrentP Munro
- The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Linda H L Lua
- The University of Queensland, Brisbane, Queensland, 4072, Australia
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3
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Pashirova TN, Bogdanov A, Masson P. Therapeutic nanoreactors for detoxification of xenobiotics: Concepts, challenges and biotechnological trends with special emphasis to organophosphate bioscavenging. Chem Biol Interact 2021; 346:109577. [PMID: 34274336 DOI: 10.1016/j.cbi.2021.109577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/19/2021] [Accepted: 07/12/2021] [Indexed: 12/20/2022]
Abstract
The introduction of enzyme nanoreactors in medicine is relatively new. However, this technology has already been experimentally successful in cancer treatments, struggle against toxicity of reactive oxygen species in inflammatory processes, detoxification of drugs and xenobiotics, and correction of metabolic and genetic defects by using encapsulated enzymes, acting in single or cascade reactions. Biomolecules, e.g. enzymes, antibodies, reactive proteins capable of inactivating toxicants in the body are called bioscavengers. In this review, we focus on enzyme-containing nanoreactors for in vivo detoxification of organophosphorous compounds (OP) to be used for prophylaxis and post-exposure treatment of OP poisoning. A particular attention is devoted to bioscavenger-containing injectable nanoreactors operating in the bloodstream. The nanoreactor concept implements single or multiple enzymes and cofactors co-encapsulated in polymeric semi-permeable nanocontainers. Thus, the detoxification processes take place in a confined space containing highly concentrated bioscavengers. The article deals with historical and theoretical backgrounds about enzymatic detoxification of OPs in nanoreactors, nanoreactor polymeric enveloppes, realizations and advantages over other approaches using bioscavengers.
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Affiliation(s)
- Tatiana N Pashirova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Andrei Bogdanov
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Patrick Masson
- Kazan Federal University, Neuropharmacology Laboratory, Kremlevskaya str., 18, Kazan, 420111, Russian Federation.
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4
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Organophosphate detoxification by membrane-engineered red blood cells. Acta Biomater 2021; 124:270-281. [PMID: 33529769 DOI: 10.1016/j.actbio.2021.01.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/31/2022]
Abstract
Biotherapeutics have achieved global economic success due to their high specificity towards their drug targets, providing exceptional safety and efficiency. The ongoing shift away from small molecule drugs towards biotherapeutics heightens the need to further improve the pharmacokinetics of these biological drugs. Three pervasive obstacles that limit the therapeutic capacity of biotherapeutics are proteolytic degradation, circulating half-life, and the development of anti-drug antibodies. These challenges can culminate in limited efficiency and consequently warrant the need for higher drug doses and more frequent administration. We have explored the coupling of biotherapeutics to long-lived and biocompatible red blood cells (RBCs) to address limited pharmacokinetics. Butyrylcholinesterase (BChE), for example, provides prophylactic protection against organophosphate nerve agents (OPNAs), yet the short circulation life of the drug requires extraordinary doses. Herein, we report the rapid and tunable chemical engineering of BChE to RBC membranes to create a cell-based delivery system that retains the enzyme activity and enhances stability. In a three-step process that first pre-modifies BChE with a cell-reactive polymer chain, primes the cells for engineering, and then grafts the conjugates to the cells, we attached over 2 million BChE molecules to the surface of each RBC without diminishing the bioscavenging capacity of the enzyme. Critically, this membrane-engineering approach was cell-tolerated with minimal hemolysis observed. These results provide strong evidence for the ability of engineered RBCs to serve as an enhanced biotherapeutic delivery vehicle. STATEMENT OF SIGNIFICANCE: Organophosphate nerve agents (OPNAs) are one of the most lethal forms of chemical warfare. After exposure to OPNAs, a patient is given life-saving therapeutics, such as atropine and oxime. However, these drugs are limited, and the patient can still suffer from irreparable injuries. Given the toxicity of OPNAs, access to a prophylactic is vital. We have created an enhanced delivery system for prophylactic butyrylcholinesterase (BChE) by engineering this biotherapeutic to the red blood cell (RBC) surface. In three simple steps that first pre-modifies BChE with a cell-reactive polymer, primes the cells for engineering, and then grafts the conjugates to the cells, we attached over 2 million BChE molecules to a single RBC while retaining the enzyme's activity and enhancing its stability.
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Hrvat NM, Kovarik Z. Counteracting poisoning with chemical warfare nerve agents. Arh Hig Rada Toksikol 2020; 71:266-284. [PMID: 33410774 PMCID: PMC7968514 DOI: 10.2478/aiht-2020-71-3459] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/01/2020] [Accepted: 11/01/2020] [Indexed: 12/14/2022] Open
Abstract
Phosphylation of the pivotal enzyme acetylcholinesterase (AChE) by nerve agents (NAs) leads to irreversible inhibition of the enzyme and accumulation of neurotransmitter acetylcholine, which induces cholinergic crisis, that is, overstimulation of muscarinic and nicotinic membrane receptors in the central and peripheral nervous system. In severe cases, subsequent desensitisation of the receptors results in hypoxia, vasodepression, and respiratory arrest, followed by death. Prompt action is therefore critical to improve the chances of victim's survival and recovery. Standard therapy of NA poisoning generally involves administration of anticholinergic atropine and an oxime reactivator of phosphylated AChE. Anticholinesterase compounds or NA bioscavengers can also be applied to preserve native AChE from inhibition. With this review of 70 years of research we aim to present current and potential approaches to counteracting NA poisoning.
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Affiliation(s)
| | - Zrinka Kovarik
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
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6
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Rosenberg Y, Saxena A. Acetylcholinesterase inhibition resulting from exposure to inhaled OP can be prevented by pretreatment with BChE in both macaques and minipigs. Neuropharmacology 2020; 174:108150. [PMID: 32442543 PMCID: PMC7365266 DOI: 10.1016/j.neuropharm.2020.108150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/05/2020] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
Abstract
More frequent and widespread nerve agent attacks highlight the need for efficacious pre- and post-exposure organophosphate (OP) counter-measures to protect military and civilian populations. Because of critical targeting of acetylcholinesterase (AChE) in the CNS by OPs, a pre-treatment candidate for preventing/reducing poisoning will be a broadly acting molecule that scavenges OPs in blood before they reach their physiological targets. Prophylactic human butyrylcholinesterase (HuBChE), the leading pretreatment candidate, has been shown to protect against multiple LD50's of nerve agents in rodents, macaques, and minipigs. This review describes the development of a HuBChE bioscavenger pretreatment from early proof-of-concept studies to pre-clinical studies with the native injectable enzyme and the development of aerosolized forms of recombinant enzyme, which can be delivered by inhalation nebulizer devices, to effect protection against inhaled OP nerve agents and insecticides. Early animal studies utilized parenteral exposure. However, lungs are the portal of entry for most volatile OP vapors and represent the major means of OP intoxication. In this regard, pretreat-ment with 7.5 mg/kg of HuBChE by IM injection protected minipigs against lethal sarin vapor and prevented AChE inhibition in the blood. This is similar to the five-day protection in macaques by an aerosolized rHuBChE using a nebulizer against aerosolized paraoxon (estimated to be an 8 mg/kg estimated human dose). Importantly, lethal inhaled doses of OP may be smaller relative to the same dose delivered by injection, thus reducing the protective HuBChE dose, while a combination of HuBChE and post-exposure oxime may prolong protection.
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Affiliation(s)
| | - Ashima Saxena
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
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Zhang L, Murata H, Amitai G, Smith PN, Matyjaszewski K, Russell AJ. Catalytic Detoxification of Organophosphorus Nerve Agents by Butyrylcholinesterase-Polymer-Oxime Bioscavengers. Biomacromolecules 2020; 21:3867-3877. [DOI: 10.1021/acs.biomac.0c00959] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Libin Zhang
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Hironobu Murata
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Gabriel Amitai
- Wohl Drug Discovery Institute, Nancy and Stephen Grand Israel National Center for Personalized Medicine (G-INCPM), Weizmann Institute of Science, Rehovot 760001, Israel
| | - Paige N. Smith
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Krzysztof Matyjaszewski
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Alan J. Russell
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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8
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diTargiani RC, Belinskaya T, Tipparaju P, Lockridge O, Saxena A. Proline 285 is integral for the reactivation of organophosphate-inhibited human butyrylcholinesterase by 2-PAM. Chem Biol Interact 2020; 324:109092. [PMID: 32278739 DOI: 10.1016/j.cbi.2020.109092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/24/2020] [Accepted: 04/05/2020] [Indexed: 11/15/2022]
Abstract
Human butyrylcholinesterase (HuBChE) is a stoichiometric bioscavenger that protects from the toxicity of nerve agents. Non-human primates are suitable models for toxicity studies that cannot be performed in humans. We evaluated the biochemical properties of native macaque (MaBChE) tetramers, compared to recombinant MaBChE monomers, PEGylated recombinant MaBChE tetramers and monomers, and native HuBChE tetramers. Km and kcat values for butyrylthiocholine were independent of subunit assembly status. The Km for all forms of MaBChE was about 70 μM, compared to 13 μM for HuBChE. The kcat was about 100,000 min-1 for MaBChE and 30,000 min-1 for HuBChE. The reversible inhibitor ethopropazine had similar Ki values of 0.05 μM for all MaBChE forms and HuBChE. The bimolecular rate constant, ki, for inhibition by diisopropylfluorophosphate (DFP), an analog of sarin, was 2.2 to 2.5 × 107 M-1 min-1 for all MaBChE forms and for HuBChE. A major difference between MaBChE and HuBChE was the rate of reactivation by 2-PAM. The second order rate constant for reactivation of DFP-inhibited MaBChE by 2-PAM was 1.4 M-1 min-1, but was 380 fold faster for DFP-inhibited HuBChE (kr 531 M-1 min-1). The acyl pocket of MaBChE has Leu285 in place of Pro285 in HuBChE. The reactivation rate of DFP-inhibited HuBChE mutant P285L by 2-PAM was reduced 5.8-fold (kr 92 M-1 min-1) indicating that P285 determines whether 2-PAM binds in an orientation that favors release of diisopropylphosphate. DFP-inhibited MaBChE treated with 0.2 M 2-PAM recovered 10% of its original activity, whereas DFP-inhibited HuBChE recovered 80% activity. It was concluded that the biochemical properties of MaBChE are similar to those of HuBChE except for the reactivation of DFP-inhibited BChE.
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Affiliation(s)
- Robert C diTargiani
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
| | - Tatyana Belinskaya
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
| | - Prasanthi Tipparaju
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
| | - Oksana Lockridge
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE 68198.
| | - Ashima Saxena
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
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9
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Rosenberg Y, Fink J, MacLoughlin R, Ooms-Konecny T, Sullivan D, Gerk W, Mao L, Jiang X, Lees J, Urban L, Rajendran N. Aerosolized recombinant human butyrylcholinesterase delivered by a nebulizer provides long term protection against inhaled paraoxon in macaques. Chem Biol Interact 2019; 309:108712. [PMID: 31201777 DOI: 10.1016/j.cbi.2019.06.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/05/2019] [Accepted: 06/11/2019] [Indexed: 02/07/2023]
Abstract
The recent intentional use of nerve agents and pesticides in Europe and Afghanistan highlights the need for an effective countermeasure against organophosphates (OP) toxins. The most developed pretreatment candidate to date is plasma (native) human butyrylcholinesterase (HuBChE), which is limited in availability and because of its 1:1 stoichiometry with OPs, a large dose will present challenges when delivered parenterally both in terms of pharmacokinetics and manageability in the field. A tetrameric recombinant (r) form of human BChE produced in CHO-K1 cells with similar structure, in vivo stability and antidotal efficacy as the native form, has been developed to deliver rHuBChE as an aerosol (aer) to form a pulmonary bioshield capable of neutralizing inhaled OPs in situ and prevent AChE inhibition in the blood and in the brain; the latter associated with the symptoms of OP toxicity. Previous proof-of-concept macaque studies demonstrated that delivery of 9 mg/kg using a microsprayer inserted down the trachea, resulted in protection against an inhaled dose of 15ug/kg of aer-paraoxon (aer-Px) given 72 h later. In the present studies, pulmonary delivery of rHuBChE in macaques was achieved using Aerogen vibrating mesh nebulizers, similar to that used for human self-administration. The promising findings indicate that despite the poor lung deposition observed in macaques using nebulizers (13-20%), protective levels of RBC-AChE were still present in the blood even when exposure aer-Px (55 μg/kg) was delayed for five days. This long term retention of 5 mg/kg rHuBChE deposited in the lung bodes well for the use of an aer-rHuBChE pretreatment in humans where a user-friendly customized nebulizer with increased lung deposition up to 50% will provide even longer protection at a lower dose.
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Affiliation(s)
| | - James Fink
- Department of Respiratory Care, Texas State University, Round Rock, TX, 78665, USA
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10
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Braid LR, Wood CA, Ford BN. Human umbilical cord perivascular cells: A novel source of the organophosphate antidote butyrylcholinesterase. Chem Biol Interact 2019; 305:66-78. [PMID: 30926319 DOI: 10.1016/j.cbi.2019.03.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 03/20/2019] [Accepted: 03/25/2019] [Indexed: 01/06/2023]
Abstract
Human butyrylcholinesterase (BChE) is a well-characterized bioscavenger with significant potential as a prophylactic or post-exposure treatment for organophosphate poisoning. Despite substantial efforts, BChE has proven technically challenging to produce in recombinant systems. Recombinant BChE tends to be insufficiently or incorrectly glycosylated, and consequently exhibits a truncated half-life, compromised activity, or is immunogenic. Thus, expired human plasma remains the only reliable source of the benchmark BChE tetramer, but production is costly and time intensive and presents possible blood-borne disease hazards. Here we report a human BChE production platform that produces functionally active, tetrameric BChE enzyme, without the addition of external factors such as polyproline peptides or chemical or gene modification required by other systems. Human umbilical cord perivascular cells (HUCPVCs) are a rich population of mesenchymal stromal cells (MSCs) derived from Wharton's jelly. We show that HUCPVCs naturally and stably secrete BChE during culture in xeno- and serum-free media, and can be gene-modified to increase BChE output. However, BChE secretion from HUCPVCs is limited by innate feedback mechanisms that can be interrupted by addition of miR 186 oligonucleotide mimics or by competitive inhibition of muscarinic cholinergic signalling receptors by addition of atropine. By contrast, adult bone marrow-derived mesenchymal stromal cells neither secrete measurable levels of BChE naturally, nor after gene modification. Further work is required to fully characterize and disable the intrinsic ceiling of HUCPVC-mediated BChE secretion to achieve commercially relevant enzyme output. However, HUCPVCs present a unique opportunity to produce both native and strategically engineered recombinant BChE enzyme in a human platform with the innate capacity to secrete the benchmark human plasma form.
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Affiliation(s)
- Lorena R Braid
- Aurora BioSolutions Inc., PO Box 21053, Crescent Heights PO, Medicine Hat, AB, T1A 6N0, Canada.
| | - Catherine A Wood
- Aurora BioSolutions Inc., PO Box 21053, Crescent Heights PO, Medicine Hat, AB, T1A 6N0, Canada
| | - Barry N Ford
- DRDC Suffield Research Centre, Casualty Management Section, Box 4000 Station Main, Medicine Hat, AB, T1A 8K6, Canada
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Wang Q, Chen CH, Chung CY, Priola J, Chu JH, Tang J, Ulmschneider MB, Betenbaugh MJ. Proline-Rich Chaperones Are Compared Computationally and Experimentally for Their Abilities to Facilitate Recombinant Butyrylcholinesterase Tetramerization in CHO Cells. Biotechnol J 2017; 13:e1700479. [DOI: 10.1002/biot.201700479] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/26/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Qiong Wang
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University; 221 Maryland Hall, 3400 N. Charles St. Baltimore Maryland 21218 USA
| | - Charles H. Chen
- Department of Materials Science and Engineering, Johns Hopkins University; 204C Shaffer Hall, 3400 N. Charles St. Baltimore Maryland 21218 USA
- Department of Chemistry, King's College London; Britannia House, 7 Trinity Street London SE1 1DB UK
| | - Cheng-yu Chung
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University; 221 Maryland Hall, 3400 N. Charles St. Baltimore Maryland 21218 USA
| | - Joseph Priola
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University; 221 Maryland Hall, 3400 N. Charles St. Baltimore Maryland 21218 USA
| | - Jeffrey H. Chu
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University; 221 Maryland Hall, 3400 N. Charles St. Baltimore Maryland 21218 USA
| | - Juechun Tang
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University; 221 Maryland Hall, 3400 N. Charles St. Baltimore Maryland 21218 USA
| | - Martin B. Ulmschneider
- Department of Materials Science and Engineering, Johns Hopkins University; 204C Shaffer Hall, 3400 N. Charles St. Baltimore Maryland 21218 USA
- Department of Chemistry, King's College London; Britannia House, 7 Trinity Street London SE1 1DB UK
| | - Michael J. Betenbaugh
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University; 221 Maryland Hall, 3400 N. Charles St. Baltimore Maryland 21218 USA
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12
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Rosenberg YJ, Mao L, Jiang X, Lees J, Zhang L, Radic Z, Taylor P. Post-exposure treatment with the oxime RS194B rapidly reverses early and advanced symptoms in macaques exposed to sarin vapor. Chem Biol Interact 2017; 274:50-57. [PMID: 28693885 PMCID: PMC5586507 DOI: 10.1016/j.cbi.2017.07.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 01/04/2023]
Abstract
Organophosphate (OP) nerve agents and pesticides trigger a common mechanism of neurotoxicity resulting from critical targeting and inhibition of acetylcholinesterases (AChE) in central and peripheral synapses in the cholinergic nervous system. Therapeutic countermeasures have thus focused on either administering an oxime post-exposure, that can rapidly reactivate OP-inhibited AChE, or by preventing OP poisoning through administering pre-exposure treatments that scavenge OPs before they inhibit their physiological AChE targets. While several pyridinium aldoxime antidotes are currently approved, their utility is impaired due to their inability to cross the blood-brain barrier (BBB) efficiently. The present study utilized a macaque (Ma) model to demonstrate the efficacy of a novel zwitterionic and centrally acting oxime RS194B to reactivate sarin- and paraoxon-inhibited macaque AChE and butyrylcholinesterase (BChE) in vitro and to further assess the capacity of RS194B to effect a reversal of clinical symptoms following sarin inhalation in vivo. In vitro, oxime reactivation of MaAChE and MaBChE was shown to be comparable to their human orthologs, while the macaque studies indicated that IM administration of 62.5 mg/kg of RS194B and 0.28 mg/kg atropine after continuous exposure to 49.6 μg/kg sarin vapor, rapidly reactivated the inhibited AChE and BChE in blood and reversed both early and advanced clinical symptoms of sarin-induced toxicity following pulmonary exposure within 1 h. The rapid cessation of autonomic and central symptoms, including convulsions, observed in macaques bodes well for the use of RS194B as an intra- or post-exposure human treatment and validates the macaque model in generating efficacy and toxicology data required for approval under the FDA Animal rule.
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Affiliation(s)
| | | | | | | | - Limin Zhang
- Department of Pharmacology, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla 92093-0650, USA.
| | - Zoran Radic
- Department of Pharmacology, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla 92093-0650, USA.
| | - Palmer Taylor
- Department of Pharmacology, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla 92093-0650, USA.
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13
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Masson P, Nachon F. Cholinesterase reactivators and bioscavengers for pre- and post-exposure treatments of organophosphorus poisoning. J Neurochem 2017; 142 Suppl 2:26-40. [PMID: 28542985 DOI: 10.1111/jnc.14026] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/02/2017] [Accepted: 03/10/2017] [Indexed: 12/11/2022]
Abstract
Organophosphorus agents (OPs) irreversibly inhibit acetylcholinesterase (AChE) causing a major cholinergic syndrome. The medical counter-measures of OP poisoning have not evolved for the last 30 years with carbamates for pretreatment, pyridinium oximes-based AChE reactivators, antimuscarinic drugs and neuroprotective benzodiazepines for post-exposure treatment. These drugs ensure protection of peripheral nervous system and mitigate acute effects of OP lethal doses. However, they have significant limitations. Pyridostigmine and oximes do not protect/reactivate central AChE. Oximes poorly reactivate AChE inhibited by phosphoramidates. In addition, current neuroprotectants do not protect the central nervous system shortly after the onset of seizures when brain damage becomes irreversible. New therapeutic approaches for pre- and post-exposure treatments involve detoxification of OP molecules before they reach their molecular targets by administrating catalytic bioscavengers, among them phosphotriesterases are the most promising. Novel generation of broad spectrum reactivators are designed for crossing the blood-brain barrier and reactivate central AChE. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms.
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Affiliation(s)
- Patrick Masson
- Neuropharmacology Laboratory, Kazan Federal University, Kazan, Russia
| | - Florian Nachon
- Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, Cédex, France
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14
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Iyengar ARS, Pande AH. Organophosphate-Hydrolyzing Enzymes as First-Line of Defence Against Nerve Agent-Poisoning: Perspectives and the Road Ahead. Protein J 2016; 35:424-439. [DOI: 10.1007/s10930-016-9686-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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15
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Masson P. Novel approaches in prophylaxis/pretreatment and treatment of organophosphorus poisoning. PHOSPHORUS SULFUR 2016. [DOI: 10.1080/10426507.2016.1211652] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Patrick Masson
- Neuropharmacology Laboratory, Kazan Federal University, Kazan, Russian Federation
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16
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Rosenberg YJ, Fink JB. Creation of a protective pulmonary bioshield against inhaled organophosphates using an aerosolized bioscavenger. Ann N Y Acad Sci 2016; 1374:151-8. [PMID: 27371808 DOI: 10.1111/nyas.13106] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 04/18/2016] [Accepted: 04/22/2016] [Indexed: 01/15/2023]
Abstract
In addition to the global use of organophosphate (OP) pesticides for agriculture, OP nerve agents and pesticides have been employed on battlefields and by terrorists (e.g., a recent sarin attack in Syria). These occurrences highlight the need for an effective countermeasure against OP exposure. Human butyrylcholinesterase (HuBChE) is a leading candidate, but injection of the high doses required for protection present pharmacokinetic challenges. An aerosolized recombinant form (aer-rHuBChE) that can neutralize inhaled OPs at the portal of entry has been assessed for its efficacy in protecting macaques against respiratory toxicity following inhalation exposure to the pesticide paraoxon (aer-Px). While protection in macaques has been demonstrated using the MicroSprayer® delivery device, administration to humans will likely employ a vibrating mesh nebulizer (VMN). Compared to the 50-70% lung deposition achieved in adult humans with a VMN, deposition in macaques is <5%, an initial major obstacle to demonstrating protection. Such problems have been partly overcome by using a more efficient modified VMN and proportionally higher doses, which together generate an effective rHuBChE pulmonary bioshield and protect against high levels of inhaled Px.
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Affiliation(s)
| | - James B Fink
- Department of Respiratory Care, Georgia State, University, Atlanta, Georgia
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17
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Terekhov S, Smirnov I, Bobik T, Shamborant O, Zenkova M, Chernolovskaya E, Gladkikh D, Murashev A, Dyachenko I, Palikov V, Palikova Y, Knorre V, Belogurov A, Ponomarenko N, Blackburn GM, Masson P, Gabibov A. A novel expression cassette delivers efficient production of exclusively tetrameric human butyrylcholinesterase with improved pharmacokinetics for protection against organophosphate poisoning. Biochimie 2015; 118:51-9. [DOI: 10.1016/j.biochi.2015.07.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 07/30/2015] [Indexed: 10/23/2022]
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18
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Pharmacokinetics and immunogenicity of a recombinant human butyrylcholinesterase bioscavenger in macaques following intravenous and pulmonary delivery. Chem Biol Interact 2015; 242:219-26. [PMID: 26415620 DOI: 10.1016/j.cbi.2015.09.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/17/2015] [Accepted: 09/22/2015] [Indexed: 10/23/2022]
Abstract
Recombinant (r) and native butyrylcholinesterse (BChE) are potent bioscavengers of organophosphates (OPs) such as nerve agents and pesticides and are undergoing development as antidotal treatments for OP-induced toxicity. Because of the lethal properties of such agents, regulatory approval will require extensive testing under the Animal Rule. However, human (Hu) glycoprotein biologicals, such as BChE, present a challenge for assessing immunogenicity and efficacy in heterologous animal models since any immune responses to the small species differences in amino acids or glycans between the host and biologic may alter pharmacodynamics and preclude accurate efficacy testing; possibly underestimating their potential protective value in humans. To establish accurate pharmacokinetic and efficacy data, an homologous animal model has been developed in which native and PEGylated forms of CHO-derived rMaBChE were multiply injected into homologous macaques with no induction of antibody. These now serve as controls for assessing the pharmacokinetics and immunogenicity in macaques of multiple administrations of PEGylated and unmodified human rBChE (rHuBChE) by both intravenous (IV) and pulmonary routes. The results indicate that, except for maximal concentration (Cmax), the pharmacokinetic parameters following IV injection with heterologous PEG-rHuBChE were greatly reduced even after the first injection compared with homologous PEG-rMaBChE. Anti-HuBChE antibody responses were induced in all monkeys after the second and third administrations regardless of the route of delivery; impacting rates of clearance and usually resulting in reduced endogenous MaBChE activity. These data highlight the difficulties inherent in assessing pharmacokinetics and immunogenicity in animal models, but bode well for the efficacy and safety of rHuBChE pretreatments in homologous humans.
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19
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Noy-Porat T, Cohen O, Ehrlich S, Epstein E, Alcalay R, Mazor O. Acetylcholinesterase-Fc Fusion Protein (AChE-Fc): A Novel Potential Organophosphate Bioscavenger with Extended Plasma Half-Life. Bioconjug Chem 2015; 26:1753-8. [DOI: 10.1021/acs.bioconjchem.5b00305] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Tal Noy-Porat
- Departments
of Biochemistry and Molecular Genetics and ‡Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Ofer Cohen
- Departments
of Biochemistry and Molecular Genetics and ‡Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Sharon Ehrlich
- Departments
of Biochemistry and Molecular Genetics and ‡Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Eyal Epstein
- Departments
of Biochemistry and Molecular Genetics and ‡Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Ron Alcalay
- Departments
of Biochemistry and Molecular Genetics and ‡Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Ohad Mazor
- Departments
of Biochemistry and Molecular Genetics and ‡Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
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20
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Lockridge O. Review of human butyrylcholinesterase structure, function, genetic variants, history of use in the clinic, and potential therapeutic uses. Pharmacol Ther 2014; 148:34-46. [PMID: 25448037 DOI: 10.1016/j.pharmthera.2014.11.011] [Citation(s) in RCA: 277] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 11/17/2014] [Indexed: 10/24/2022]
Abstract
Phase I clinical trials have shown that pure human butyrylcholinesterase (BChE) is safe when administered to humans. A potential therapeutic use of BChE is for prevention of nerve agent toxicity. A recombinant mutant of BChE that rapidly inactivates cocaine is being developed as a treatment to help recovering cocaine addicts avoid relapse into drug taking. These clinical applications rely on knowledge of the structure, stability, and properties of BChE, information that is reviewed here. Gene therapy with a vector that sustains expression for a year from a single injection is a promising method for delivering therapeutic quantities of BChE.
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Affiliation(s)
- Oksana Lockridge
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE 68198-5950, USA.
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21
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Schneider JD, Marillonnet S, Castilho A, Gruber C, Werner S, Mach L, Klimyuk V, Mor TS, Steinkellner H. Oligomerization status influences subcellular deposition and glycosylation of recombinant butyrylcholinesterase in Nicotiana benthamiana. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:832-9. [PMID: 24618259 PMCID: PMC4265266 DOI: 10.1111/pbi.12184] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 12/15/2013] [Indexed: 05/20/2023]
Abstract
Plants have a proven track record for the expression of biopharmaceutically interesting proteins. Importantly, plants and mammals share a highly conserved secretory pathway that allows similar folding, assembly and posttranslational modifications of proteins. Human butyrylcholinesterase (BChE) is a highly sialylated, tetrameric serum protein, investigated as a bioscavenger for organophosphorous nerve agents. Expression of recombinant BChE (rBChE) in Nicotiana benthamiana results in accumulation of both monomers as well as assembled oligomers. In particular, we show here that co-expression of BChE with a novel gene-stacking vector, carrying six mammalian genes necessary for in planta protein sialylation, resulted in the generation of rBChE decorated with sialylated N-glycans. The N-glycosylation profile of monomeric rBChE secreted to the apoplast largely resembles the plasma-derived orthologue. In contrast, rBChE purified from total soluble protein extracts was decorated with a significant portion of ER-typical oligomannosidic structures. Biochemical analyses and live-cell imaging experiments indicated that impaired N-glycan processing is due to aberrant deposition of rBChE oligomers in the endoplasmic reticulum or endoplasmic-reticulum-derived compartments. In summary, we show the assembly of rBChE multimers, however, also points to the need for in-depth studies to explain the unexpected subcellular targeting of oligomeric BChE in plants.
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Affiliation(s)
- Jeannine D Schneider
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life SciencesVienna, Austria
| | | | - Alexandra Castilho
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life SciencesVienna, Austria
| | - Clemens Gruber
- Department of Chemistry, University of Natural Resources and Life SciencesVienna, Austria
| | | | - Lukas Mach
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life SciencesVienna, Austria
| | | | - Tsafrir S Mor
- The Biodesign Institute, Arizona State UniversityTempe, Arizona, USA
| | - Herta Steinkellner
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life SciencesVienna, Austria
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22
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Protection against paraoxon toxicity by an intravenous pretreatment with polyethylene-glycol-conjugated recombinant butyrylcholinesterase in macaques. Chem Biol Interact 2013; 210:20-5. [PMID: 24384224 DOI: 10.1016/j.cbi.2013.12.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 11/27/2013] [Accepted: 12/20/2013] [Indexed: 11/23/2022]
Abstract
Recombinant (r) butyrylcholinesterase (rBChE) produced in CHO cells is being developed as a prophylactic countermeasure against neurotoxicity resulting from exposure to organophosphates (OPs) in the form of pesticides and nerve agents. To evaluate the efficacy of a parenteral pretreatment, a PEGylated macaque (Ma) form of rBChE was administered into homologous animals to ensure good plasma retention without immunogenicity. Thus, macaques were administered PEG-rMaBChE at either 5 or 7mg/kg intravenously (i.v.) and exposed subcutaneously to 12μg/kg of the potent pesticide paraoxon (Px) at 1h or at 1 and 72h, respectively. Protection was measured by the ability of rBChE prophylaxis to prevent the inhibition of circulating acetylcholinesterase on red blood cells (RBC-AChE). In rBChE-pretreated animals, no inhibition of RBC-AChE activity after the first Px exposure and only a 10-20% reduction after the second exposure were observed as compared to a 75% RBC-AChE inhibition usually obtained without pretreatment. In addition, these studies raised other interesting issues. The lipophilic nature of Px, appears to result in early and transient inhibition of RBC-AChE as a result of transfer of OP bound to RBC even in BChE-pretreated animals. The protection by a single injection of rBChE against two administrations of Px represents the first example of protection by an i.v. rBChE pretreatment against a pesticide such as Px and bodes well for a parenteral rHuBChE pretreatment as an OP countermeasure in humans.
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23
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Hou S, Xue L, Yang W, Fang L, Zheng F, Zhan CG. Substrate selectivity of high-activity mutants of human butyrylcholinesterase. Org Biomol Chem 2013; 11:7477-85. [PMID: 24077614 PMCID: PMC3836059 DOI: 10.1039/c3ob41713a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cocaine is one of the most addictive drugs, and there is still no FDA (Food and Drug Administration)-approved medication specific for cocaine abuse. A promising therapeutic strategy is to accelerate cocaine metabolism, producing biologically inactive metabolites via a route similar to the primary cocaine-metabolizing pathway, i.e. cocaine hydrolysis catalyzed by butyrylcholinesterase (BChE) in plasma. However, the native BChE has a low catalytic efficiency against the abused cocaine, i.e. (-)-cocaine. Our recently designed and discovered A199S/F227A/S287G/A328W/Y332G mutant and other mutants of human BChE have a considerably improved catalytic efficiency against (-)-cocaine. In the present study, we carried out both computational modeling and experimental kinetic analysis on the catalytic activities of these promising new BChE mutants against other known substrates, including neurotransmitter acetylcholine (ACh), acetylthiocholine (ATC), butyrylthiocholine (BTC), and (+)-cocaine, in comparison with the corresponding catalytic activity against (-)-cocaine. Both the computational modeling and kinetic analysis have consistently revealed that all the examined amino acid mutations only considerably improve the catalytic efficiency of human BChE against (-)-cocaine, without significantly improving the catalytic efficiency of the enzyme against any of the other substrates examined. In particular, all the examined BChE mutants have a slightly lower catalytic efficiency against neurotransmitter ACh compared to the wild-type BChE. This observation gives us confidence in developing an anti-cocaine enzyme therapy by using one of these BChE mutants, particularly the A199S/F227A/S287G/A328W/Y332G mutant.
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Affiliation(s)
- Shurong Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA.
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24
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Brimijoin S, Shen X, Orson F, Kosten T. Prospects, promise and problems on the road to effective vaccines and related therapies for substance abuse. Expert Rev Vaccines 2013; 12:323-32. [PMID: 23496671 DOI: 10.1586/erv.13.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review addresses potential new treatments for stimulant drugs of abuse, especially cocaine. Clinical trials of vaccines against cocaine and nicotine have been completed with the generally encouraging result that subjects showing high titers of antidrug antibody experience a reduction in drug reward, which may aid in cessation. New vaccine technologies, including gene transfer of highly optimized monoclonal antibodies, are likely to improve such outcomes further. In the special case of cocaine abuse, a metabolic enzyme is emerging as an alternative or added therapeutic intervention, which would also involve gene transfer. Such approaches still require extensive studies of safety and efficacy, but they may eventually contribute to a robust form of in vivo drug interception that greatly reduces the risks of addiction relapse.
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Affiliation(s)
- Stephen Brimijoin
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.
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25
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Geng L, Gao Y, Chen X, Hou S, Zhan CG, Radic Z, Parks RJ, Russell SJ, Pham L, Brimijoin S. Gene transfer of mutant mouse cholinesterase provides high lifetime expression and reduced cocaine responses with no evident toxicity. PLoS One 2013; 8:e67446. [PMID: 23840704 PMCID: PMC3696080 DOI: 10.1371/journal.pone.0067446] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 05/18/2013] [Indexed: 11/18/2022] Open
Abstract
Gene transfer of a human cocaine hydrolase (hCocH) derived from butyrylcholinesterase (BChE) by 5 mutations (A199S/F227A/S287G/A328W/Y332G) has shown promise in animal studies for treatment of cocaine addiction. To predict the physiological fate and immunogenicity of this enzyme in humans, a comparable enzyme was created and tested in a conspecific host. Thus, similar mutations (A199S/S227A/S287G/A328W/Y332G) were introduced into mouse BChE to obtain a mouse CocH (mCocH). The cDNA was incorporated into viral vectors based on: a) serotype-5 helper-dependent adenovirus (hdAD) with ApoE promoter, and b) serotype-8 adeno-associated virus with CMV promoter (AAV-CMV) or multiple promoter and enhancer elements (AAV-VIP). Experiments on substrate kinetics of purified mCocH expressed in HEK293T cells showed 30-fold higher activity (U/mg) with 3H-cocaine and 25% lower activity with butyrylthiocholine, compared with wild type BChE. In mice given modest doses of AAV-CMV-mCocH vector (0.7 or 3×1011 particles) plasma hydrolase activity rose 10-fold above control for over one year with no observed immune response. Under the same conditions, transduction of the human counterpart continued less than 2 months and antibodies to hCocH were readily detected. The advanced AAV-VIP-mCocH vector generated a dose-dependent rise in plasma cocaine hydrolase activity from 20-fold (1010 particles) to 20,000 fold (1013 particles), while the hdAD vector (1.7×1012 particles) yielded a 300,000-fold increase. Neither vector caused adverse reactions such as motor weakness, elevated liver enzymes, or disturbance in spontaneous activity. Furthermore, treatment with high dose hdAD-ApoE-mCocH vector (1.7×1012 particles) prevented locomotor abnormalities, other behavioral signs, and release of hepatic alanine amino transferase after a cocaine dose fatal to most control mice (120 mg/kg). This outcome suggests that viral gene transfer can yield clinically effective cocaine hydrolase expression for lengthy periods without immune reactions or cholinergic dysfunction, while blocking toxicity from drug overdose.
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Affiliation(s)
- Liyi Geng
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Yang Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Xiabin Chen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, United States of America
| | - Shurong Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, United States of America
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, United States of America
| | - Zoran Radic
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, LaJolla, California, United States of America
| | - Robin J. Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Stephen J. Russell
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Linh Pham
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Stephen Brimijoin
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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26
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Nachon F, Brazzolotto X, Trovaslet M, Masson P. Progress in the development of enzyme-based nerve agent bioscavengers. Chem Biol Interact 2013; 206:536-44. [PMID: 23811386 DOI: 10.1016/j.cbi.2013.06.012] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 06/15/2013] [Accepted: 06/18/2013] [Indexed: 11/17/2022]
Abstract
Acetylcholinesterase is the physiological target for acute toxicity of nerve agents. Attempts to protect acetylcholinesterase from phosphylation by nerve agents, is currently achieved by reversible inhibitors that transiently mask the enzyme active site. This approach either protects only peripheral acetylcholinesterase or may cause side effects. Thus, an alternative strategy consists in scavenging nerve agents in the bloodstream before they can reach acetylcholinesterase. Pre- or post-exposure administration of bioscavengers, enzymes that neutralize and detoxify organophosphorus molecules, is one of the major developments of new medical counter-measures. These enzymes act either as stoichiometric or catalytic bioscavengers. Human butyrylcholinesterase is the leading stoichiometric bioscavenger. Current efforts are devoted to its mass production with care to pharmacokinetic properties of the final product for extended lifetime. Development of specific reactivators of phosphylated butyrylcholinesterase, or variants with spontaneous reactivation activity is also envisioned for rapid in situ regeneration of the scavenger. Human paraoxonase 1 is the leading catalytic bioscavenger under development. Research efforts focus on improving its catalytic efficiency toward the most toxic isomers of nerve agents, by means of directed evolution-based strategies. Human prolidase appears to be another promising human enzyme. Other non-human efficient enzymes like bacterial phosphotriesterases or squid diisopropylfluorophosphatase are also considered though their intrinsic immunogenic properties remain challenging for use in humans. Encapsulation, PEGylation and other modifications are possible solutions to address this problem as well as that of their limited lifetime. Finally, gene therapy for in situ generation and delivery of bioscavengers is for the far future, but its proof of concept has been established.
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Affiliation(s)
- Florian Nachon
- Institut de Recherche Biomédicale des Armées, BP87, 38702 La Tronche Cédex, France.
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27
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Sun W, Luo C, Tipparaju P, Doctor BP, Saxena A. Effect of polyethylene glycol conjugation on the circulatory stability of plasma-derived human butyrylcholinesterase in mice. Chem Biol Interact 2013; 203:172-6. [DOI: 10.1016/j.cbi.2012.11.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 11/26/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
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28
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Chemical polysialylation of human recombinant butyrylcholinesterase delivers a long-acting bioscavenger for nerve agents in vivo. Proc Natl Acad Sci U S A 2013; 110:1243-8. [PMID: 23297221 DOI: 10.1073/pnas.1211118110] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The creation of effective bioscavengers as a pretreatment for exposure to nerve agents is a challenging medical objective. We report a recombinant method using chemical polysialylation to generate bioscavengers stable in the bloodstream. Development of a CHO-based expression system using genes encoding human butyrylcholinesterase and a proline-rich peptide under elongation factor promoter control resulted in self-assembling, active enzyme multimers. Polysialylation gives bioscavengers with enhanced pharmacokinetics which protect mice against 4.2 LD(50) of S-(2-(diethylamino)ethyl) O-isobutyl methanephosphonothioate without perturbation of long-term behavior.
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29
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Pulmonary delivery of an aerosolized recombinant human butyrylcholinesterase pretreatment protects against aerosolized paraoxon in macaques. Chem Biol Interact 2012. [PMID: 23178380 DOI: 10.1016/j.cbi.2012.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Butyrylcholinesterase (BChE) is the leading pretreatment candidate against exposure to organophosphates (OPs), which pose an ever increasing public and military health. Since respiratory failure is the primary cause of death following acute OP poisoning, an inhaled BChE therapeutic could prove highly efficacious in preventing acute toxicity as well as the associated delayed neuropathy. To address this, studies have been performed in mice and macaques using Chinese Hamster Ovary cells (CHO)-derived recombinant (r) BChE delivered by the pulmonary route, to examine whether the deposition of both macaque (Ma) and human (Hu) rBChE administered as aerosols (aer) favored the creation and retention of an efficient protective "pulmonary bioshield" that could scavenge incoming (inhaled) OPs in situ thereby preventing entry into the circulation and inhibition of plasma BChE and AChE on red blood cells (RBC-AChE) and in cholinergic synapses. In contrast to parenteral delivery of rBChE, which currently requires posttranslational modification for good plasma stability, an unmodified aer-rBChE pretreatment given 1-40 h prior to >1 LD50 of aer-paraoxon (Px) was able to prevent inhibition of circulating cholinesterase in a dose-dependent manner. These studies are the first to show protection by rBChE against a pesticide such as paraoxon when delivered directly into the lung and bode well for the use of a non-invasive and consumer friendly method of rHuBChE delivery as a human treatment to counteract OP toxicity.
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30
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Bahar FG, Ohura K, Ogihara T, Imai T. Species difference of esterase expression and hydrolase activity in plasma. J Pharm Sci 2012; 101:3979-88. [PMID: 22833171 DOI: 10.1002/jps.23258] [Citation(s) in RCA: 196] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 05/29/2012] [Accepted: 06/15/2012] [Indexed: 11/07/2022]
Abstract
Differences in esterase expression among human, rhesus monkey, cynomolgus monkey, dog, minipig, rabbit, rat, and mouse plasma were identified using native polyacrylamide gel electrophoresis. Paraoxonase (PON) and butyrylcholinesterase (BChE) were ubiquitous in all species, but were highly expressed in primates and dogs, whereas carboxylesterase (CES) was only abundant in rabbits, mice, and rats. Several unknown esterases were observed in minipig and mouse plasma. These differences in plasma esterases and their expression levels result in species differences with respect to hydrolase activity. These differences were characterized using several different substrates. In contrast to the high hydrolase activity found for p-nitrophenylacetate (PNPA), a substrate of several hydrolase enzymes, irinotecan, a carbamate compound, was resistant to all plasma esterases. Oseltamivir, temocapril, and propranolol (PL) derivatives were rapidly hydrolyzed in mouse and rat plasma by their highly active CES enzyme, but rabbit plasma CES hydrolyzed only the PL derivatives. Interestingly, PL derivatives were highly hydrolyzed by monkey plasma BChE, whereas BChE from human, dog, and minipig plasma showed negligible activity. In conclusion, the esterase expression and hydrolyzing pattern of dog plasma were found to be closest to that of human plasma. These differences should be considered when selecting model animals for preclinical studies.
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Affiliation(s)
- Fatma Goksin Bahar
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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Abstract
Achieving optimal patient benefit from biological therapies can be hindered by drug instability, rapid clearance requiring frequent dosing or potential immune reactions. One strategy for addressing these challenges is drug modification through PEGylation, a well established process by which one or more molecules of polyethylene glycol (PEG) are covalently attached to a biological or small-molecule drug, effectively transforming it into a therapy with improved pharmacokinetic and pharmacodynamic properties. Numerous PEGylated therapeutics are currently available, all of which have at least comparable efficacy, safety and tolerability to their unmodified forms. A PEGylated form of interferon-β-1a (PEG-IFNβ-1a) is being developed to address an unmet medical need for safer, more effective and more convenient therapies for multiple sclerosis (MS). Phase I study data suggest that PEG-IFNβ-1a should provide patients with a first-line therapy with a more convenient dosing regimen while maintaining the established efficacy, safety and tolerability of presently available IFNβ-1a. The ongoing global ADVANCE phase III study will determine the clinical efficacy of PEG-IFNβ-1a in patients with relapsing MS.
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Cochran R, Kalisiak J, Küçükkilinç T, Radic Z, Garcia E, Zhang L, Ho KY, Amitai G, Kovarik Z, Fokin VV, Sharpless KB, Taylor P. Oxime-assisted acetylcholinesterase catalytic scavengers of organophosphates that resist aging. J Biol Chem 2011; 286:29718-24. [PMID: 21730071 DOI: 10.1074/jbc.m111.264739] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase, are primary targets of organophosphates (OPs). Exposure to OPs can lead to serious cardiovascular complications, respiratory compromise, and death. Current therapy to combat OP poisoning involves an oxime reactivator (2-PAM, obidoxime, TMB4, or HI-6) combined with atropine and on occasion an anticonvulsant. Butyrylcholinesterase, administered in the plasma compartment as a bio-scavenger, has also shown efficacy but is limited by its strict stoichiometric scavenging, slow reactivation, and a propensity for aging. Here, we characterize 10 human (h) AChE mutants that, when coupled with an oxime, give rise to catalytic reactivation and aging resistance of the soman conjugate. With the most efficient human AChE mutant Y337A/F338A, we show enhanced reactivation rates for several OP-hAChE conjugates compared with wild-type hAChE when reactivated with HI-6 (1-(2'-hydroxyiminomethyl-1'-pyridinium)-3-(4'-carbamoyl-1-pyridinium)). In addition, we interrogated an 840-member novel oxime library for reactivation of Y337A/F338A hAChE-OP conjugates to delineate the most efficient oxime-mutant enzyme pairs for catalytic bio-scavenging. Combining the increased accessibility of the Y337A mutation to oximes within the space-impacted active center gorge with the aging resistance of the F338A mutation provides increased substrate diversity in scavenging potential for aging-prone alkyl phosphate inhibitors.
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Affiliation(s)
- Rory Cochran
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650, USA
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Masson P. Evolution of and perspectives on therapeutic approaches to nerve agent poisoning. Toxicol Lett 2011; 206:5-13. [PMID: 21524695 DOI: 10.1016/j.toxlet.2011.04.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 04/08/2011] [Indexed: 01/18/2023]
Abstract
After more than 70 years of considerable efforts, research on medical defense against nerve agents has come to a standstill. Major progress in medical countermeasures was achieved between the 50s and 70s with the development of anticholinergic drugs and carbamate-based pretreatment, the introduction of pyridinium oximes as antidotes, and benzodiazepines in emergency treatments. These drugs ensure good protection of the peripheral nervous system and mitigate the acute effects of exposure to lethal doses of nerve agents. However, pyridostigmine and cholinesterase reactivators currently used in the armed forces do not protect/reactivate central acetylcholinesterases. Moreover, other drugs used are not sufficiently effective in protecting the central nervous system against seizures, irreversible brain damages and long-term sequelae of nerve agent poisoning.New developments of medical counter-measures focus on: (a) detoxification of organophosphorus molecules before they react with acetylcholinesterase and other physiological targets by administration of stoichiometric or catalytic scavengers; (b) protection and reactivation of central acetylcholinesterases, and (c) improvement of neuroprotection following delayed therapy.Future developments will aim at treatment of acute and long-term effects of low level exposure to nerve agents, research on alternative routes for optimizing drug delivery, and therapies. Though gene therapy for in situ generation of bioscavengers, and cell therapy based on neural progenitor engraftment for neuronal regeneration have been successfully explored, more studies are needed before practical medical applications can be made of these new approaches.
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Affiliation(s)
- Patrick Masson
- IRBA-CRSSA, Toxicology Dept., 38702 La Tronche Cedex, France.
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