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Worek F, Thiermann H, Wille T. Organophosphorus compounds and oximes: a critical review. Arch Toxicol 2020; 94:2275-2292. [PMID: 32506210 PMCID: PMC7367912 DOI: 10.1007/s00204-020-02797-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 05/28/2020] [Indexed: 12/19/2022]
Abstract
Organophosphorus (OP) pesticides and nerve agents still pose a threat to the population. Treatment of OP poisoning is an ongoing challenge and burden for medical services. Standard drug treatment consists of atropine and an oxime as reactivator of OP-inhibited acetylcholinesterase and is virtually unchanged since more than six decades. Established oximes, i.e. pralidoxime, obidoxime, TMB-4, HI-6 and MMB-4, are of insufficient effectiveness in some poisonings and often cover only a limited spectrum of the different nerve agents and pesticides. Moreover, the value of oximes in human OP pesticide poisoning is still disputed. Long-lasting research efforts resulted in the preparation of countless experimental oximes, and more recently non-oxime reactivators, intended to replace or supplement the established and licensed oximes. The progress of this development is slow and none of the novel compounds appears to be suitable for transfer into advanced development or into clinical use. This situation calls for a critical analysis of the value of oximes as mainstay of treatment as well as the potential and limitations of established and novel reactivators. Requirements for a straightforward identification of superior reactivators and their development to licensed drugs need to be addressed as well as options for interim solutions as a chance to improve the therapy of OP poisoning in a foreseeable time frame.
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Affiliation(s)
- Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937, Munich, Germany.
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937, Munich, Germany
| | - Timo Wille
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937, Munich, Germany
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3
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Bharate SB, Chao CK, Thompson CM. Comparison of the reactivation rates of acetylcholinesterase modified by structurally different organophosphates using novel pyridinium oximes. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2019; 71:103218. [PMID: 31302432 PMCID: PMC6736693 DOI: 10.1016/j.etap.2019.103218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 03/27/2019] [Accepted: 06/24/2019] [Indexed: 06/10/2023]
Abstract
A novel panel of oximes were synthesized, which have displayed varying degree of reactivation ability towards different organophosphorus (OP) modified cholinesterases. In the present article, we report a comparative reactivation profile of a series of quaternary pyridinium-oximes for electric eel acetylcholinesterase (EEAChE) inhibited by the organophosphorus (OP) inhibitors methyl paraoxon (MePOX), ethyl paraoxon (POX; paraoxon) and diisopropyl fluorophosphate (DFP) that are distinguishable as dimethoxyphosphoryl, diethoxyphosphoryl and diisopropoxyphosphoryl AChE-OP-adducts. Most of the 59-oximes tested led to faster and more extensive reactivation of MePOX- and POX-inhibited EEAChE as compared to DFP-modified EEAChE. All were effective reactivators of three OP-modified EEAChE conjugates showing 18-21% reactivation for DFP-inhibited AChE and ≥45% reactivation for MePOX- and POX-inhibited EEAChE. Oximes 7 and 8 showed kr values better than pralidoxime (1) for DFP-inhibited EEAChE. Reactivation rates determined at different inhibition times showed no significant change in kr values during 0-90 min incubation with three OPs. However, a 34-72% decrease in kr for MePOX and POX and > 95% decrease in kr for DFP-inhibited EEAChE was observed after 24 h of OP-exposure (aging).
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Affiliation(s)
- Sandip B Bharate
- The Center for Structural and Functional Neuroscience, Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT, 59812, USA; Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu, 180001, India.
| | - Chih-Kai Chao
- The Center for Structural and Functional Neuroscience, Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT, 59812, USA
| | - Charles M Thompson
- The Center for Structural and Functional Neuroscience, Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT, 59812, USA.
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4
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Horn G, de Koning MC, van Grol M, Thiermann H, Worek F. Interactions between acetylcholinesterase, toxic organophosphorus compounds and a short series of structurally related non-oxime reactivators: Analysis of reactivation and inhibition kinetics in vitro. Toxicol Lett 2018; 299:218-225. [PMID: 30312685 DOI: 10.1016/j.toxlet.2018.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/24/2018] [Accepted: 10/05/2018] [Indexed: 12/12/2022]
Abstract
Poisoning by organophosphorus compounds (OP) is characterized by inhibition of the key enzyme acetylcholinesterase (AChE) and potentially fatal outcomes in humans. Insufficient efficacy of the standard therapy with atropine and AChE reactivators (oximes) against certain OP initiated synthesis of novel non-oxime reactivators basing on the common structure 4-amino-2-((diethylamino)methyl)phenol (ADOC). Recently, we reported of a pyrrolidine-bearing ADOC analogue (3 l) with a remarkable ability to reactivate OP-inhibited AChE. This in vitro study was undertaken to determine reactivity, affinity and overall reactivation constants of 3 l, the reference compound ADOC and two structural analogues with human AChE inhibited by paraoxon, sarin, cyclosarin and VX. The data showed a 10 to 34-fold reactivating potency of 3 l compared to ADOC mainly due to improved affinity. Additionally, various interactions between non-oximes, human or guinea pig (GP) AChE and structurally different OP were investigated: OP-inhibited guinea pig AChE was less amenable to reactivation by ADOC and 3 l than human AChE. Compound 3 l was considered as potential pretreatment to prevent AChE from irreversible inhibition by OP: In the presence of 10 μM 3 l inhibition of native human AChE was attenuated resulting in protective indices (PI) ranging from about 2.7 to 6.0. A combination of 3 l and the bispyridinium oxime HI-6 was tested to reactivate OP-inhibited AChE: The superior reactivator of the respective OP-AChE combination dominated the reactivation process and a synergistic effect could not be observed. In conclusion, novel non-oxime reactivators like 3 l may be considered as promising templates for the design of more potent therapeutics against poisoning by highly toxic OP.
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Affiliation(s)
- Gabriele Horn
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany
| | | | - Marco van Grol
- TNO, Lange Kleiweg 137, 2288 GJ Rijswijk, the Netherlands
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany.
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6
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Gorecki L, Korabecny J, Musilek K, Malinak D, Nepovimova E, Dolezal R, Jun D, Soukup O, Kuca K. SAR study to find optimal cholinesterase reactivator against organophosphorous nerve agents and pesticides. Arch Toxicol 2016; 90:2831-2859. [PMID: 27582056 DOI: 10.1007/s00204-016-1827-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 08/22/2016] [Indexed: 01/13/2023]
Abstract
Irreversible inhibition of acetylcholinesterase (AChE) by organophosphates leads to many failures in living organism and ultimately in death. Organophosphorus compounds developed as nerve agents such as tabun, sarin, soman, VX and others belong to the most toxic chemical warfare agents and are one of the biggest threats to the modern civilization. Moreover, misuse of nerve agents together with organophosphorus pesticides (e.g. malathion, paraoxon, chlorpyrifos, etc.) which are annually implicated in millions of intoxications and hundreds of thousand deaths reminds us of insufficient protection against these compounds. Basic treatments for these intoxications are based on immediate administration of atropine and acetylcholinesterase reactivators which are currently represented by mono- or bis-pyridinium aldoximes. However, these antidotes are not sufficient to ensure 100 % treatment efficacy even they are administered immediately after intoxication, and in general, they possess several drawbacks. Herein, we have reviewed new efforts leading to the development of novel reactivators and proposition of new promising strategies to design novel and effective antidotes. Structure-activity relationships and biological activities of recently proposed acetylcholinesterase reactivators are discussed and summarized. Among further modifications of known oximes, the main attention has been paid to dual binding site ligands of AChE as the current mainstream strategy. We have also discussed new chemical entities as potential replacement of oxime functional group.
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Affiliation(s)
- Lukas Gorecki
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.,Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic
| | - Jan Korabecny
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.,Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic
| | - Kamil Musilek
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.,Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic.,Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic
| | - David Malinak
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.,Department of Physiology and Pathophysiology, Faculty of Medicine, University of Ostrava, Syllabova 19, 703 00, Ostrava, Czech Republic
| | - Eugenie Nepovimova
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.,Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic
| | - Rafael Dolezal
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.,Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic
| | - Daniel Jun
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.,Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic
| | - Ondrej Soukup
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.,Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic
| | - Kamil Kuca
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic. .,Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic.
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7
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Ochoa R, Rodriguez CA, Zuluaga AF. Perspectives for the structure-based design of acetylcholinesterase reactivators. J Mol Graph Model 2016; 68:176-183. [PMID: 27450771 DOI: 10.1016/j.jmgm.2016.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/31/2016] [Accepted: 07/17/2016] [Indexed: 02/03/2023]
Abstract
Rational design of active molecules through structure-based methods has been gaining adepts during the last decades due to the wider availability of protein structures, most of them conjugated with relevant ligands. Acetylcholinesterase (AChE) is a molecular target with a considerable amount of data related to its sequence and 3-dimensional structure. In addition, there are structural insights about the mechanism of action of the natural substrate and drugs used in Alzheimer's disease, organophosphorus compounds, among others. We looked for AChE structural data useful for in silico design of potential interacting molecules. In particular, we focused on information regarding the design of ligands aimed to reactivate AChE catalytic activity. The structures of 178 AChE were annotated and categorized on different subsets according to the nature of the ligand, source organisms and experimental details. We compared sequence homology among the active site from Torpedo californica, Mus musculus and Homo sapiens with the latter two species having the closest relationship (88.9% identity). In addition, the mechanism of organophosphorus binding and the design of effective reactivators are reviewed. A curated data collection obtained with information from several sources was included for researchers working on the field. Finally, a molecular dynamics simulation with human AChE indicated that the catalytic pocket volume stabilizes around 600 Å(3), providing additional clues for drug design.
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Affiliation(s)
- Rodrigo Ochoa
- CIEMTO: Centro de Información y Estudio de Medicamentos y Tóxicos, Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad de Antioquia, Carrera 51D No. 62-42 Medellín, Colombia.
| | - Carlos A Rodriguez
- CIEMTO: Centro de Información y Estudio de Medicamentos y Tóxicos, Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad de Antioquia, Carrera 51D No. 62-42 Medellín, Colombia; GRIPE: Grupo Investigador de Problemas en Enfermedades Infecciosas, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia.
| | - Andres F Zuluaga
- CIEMTO: Centro de Información y Estudio de Medicamentos y Tóxicos, Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad de Antioquia, Carrera 51D No. 62-42 Medellín, Colombia; GRIPE: Grupo Investigador de Problemas en Enfermedades Infecciosas, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia.
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8
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Synthesis and in vitro reactivation study of isonicotinamide derivatives of 2-(hydroxyimino)-N-(pyridin-3-yl)acetamide as reactivators of Sarin and VX inhibited human acetylcholinesterase (hAChE). Bioorg Med Chem 2016; 24:4171-4176. [PMID: 27450532 DOI: 10.1016/j.bmc.2016.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 07/04/2016] [Accepted: 07/05/2016] [Indexed: 11/24/2022]
Abstract
Previously (Karade et al., 2014), we have reported the synthesis and in vitro evaluation of bis-pyridinium derivatives of pyridine-3-yl-(2-hydroxyimino acetamide), as reactivators of sarin and VX inhibited hAChE. Few of the molecules showed superior in vivo protection efficacy (mice model) (Kumar et al., 2014; Swami et al., 2016) in comparison to 2-PAM against DFP and sarin poisoning. Encouraged by these results, herein we report the synthesis and in vitro evaluation of isonicotinamide derivatives of pyridine-3-yl-(2-hydroxyimino acetamide) (4a-4d) against sarin and VX inhibited erythrocyte ghost hAChE. Reactivation kinetics of these compounds was studied and the determined kinetic parameters were compared with that of commercial reactivators viz. 2-PAM and obidoxime. In comparison to 2-PAM and obidoxime, oxime 4a and 4b exhibited enhanced reactivation efficacy toward sarin inhibited hAChE while oxime 4c showed far greater reactivation efficacy toward VX inhibited hAChE. The acid dissociation constant and IC50 values of these oximes were determined and correlated with the observed reactivation potential.
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10
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Bierwisch A, Wille T, Thiermann H, Worek F. Kinetic analysis of interactions of amodiaquine with human cholinesterases and organophosphorus compounds. Toxicol Lett 2016; 246:49-56. [PMID: 26851641 DOI: 10.1016/j.toxlet.2016.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 01/30/2016] [Accepted: 02/02/2016] [Indexed: 10/22/2022]
Abstract
Standard therapy of poisoning by organophosphorus compounds (OP) is a combined administration of an anti-muscarinic drug (e.g. atropine) and an oxime as reactivator of inhibited acetylcholinesterase (AChE). Limited efficacy of clinically used oximes against a variety of OPs was shown in numerous studies, calling for research on novel reactivators of OP-inhibited AChE. Recently, reactivation of OP-inhibited AChE by the antimalarial drug amodiaquine was reported. In the present study, amodiaquine and its interactions with human cholinesterases in presence or absence of OP nerve agents was investigated in vitro. Thereby, reversible inhibition of human cholinesterases by amodiaquine (AChE ≫ BChE) was observed. Additionally, a mixed competitive-non-competitive inhibition type of amodiaquine with human AChE was determined. Slow and partial reactivation of sarin-, cyclosarin- and VX-inhibited cholinesterases by amodiaquine was recorded, amodiaquine failed to reactivate tabun-inhibited human cholinesterases. Amodiaquine, being a potent, reversible AChE inhibitor, was tested for its potential benefit as a pretreatment to prevent complete irreversible AChE inhibition by the nerve agent soman. Hereby, amodiaquine failed to prevent phosphonylation and resulted only in a slight increase of AChE activity after removal of amodiaquine and soman. At present the molecular mechanism of amodiaquine-induced reactivation of OP-inhibited AChE is not known, nevertheless amodiaquine could be considered as a template for the design of more potent non-oxime reactivators.
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Affiliation(s)
- Anne Bierwisch
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany
| | - Timo Wille
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany
| | - Horst Thiermann
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany
| | - Franz Worek
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany.
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11
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Winter M, Wille T, Musilek K, Kuca K, Thiermann H, Worek F. Investigation of the reactivation kinetics of a large series of bispyridinium oximes with organophosphate-inhibited human acetylcholinesterase. Toxicol Lett 2015. [PMID: 26210933 DOI: 10.1016/j.toxlet.2015.07.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The limited effectiveness of the established oximes obidoxime and pralidoxime resulted in ongoing research on novel oximes for the reactivation of acetylcholinesterase (AChE) inhibited by organophosphorus compounds (OP). In order to get more insight into the ability of bispyridinium oximes to reactivate human AChE inhibited by structurally different OP the reactivation kinetics of 31 compounds was determined with tabun-, cyclosarin- and paraoxon-inhibited AChE under identical experimental conditions. The determined affinity (KD), reactivity (kr) and hybrid reactivation rate constants (kr2) enabled theoretical calculations and gave insight into distinct structural features which are important for the reactivation of AChE inhibited by different OP. Several oximes with superior reactivating potency towards selective OP-AChE conjugates were identified but none of the tested oximes can be considered as a broad spectrum reactivator. In the end, the data of this and previous studies gives rise to the question whether further modifications of the bispyridinium structure could ever result in a universal reactivator or whether future research should be directed to different templates.
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Affiliation(s)
- Michael Winter
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Timo Wille
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Kamil Musilek
- University of Hradec Kralove, Faculty of Science, Department of Chemistry, Hradec Králové, Czech Republic
| | - Kamil Kuca
- University of Hradec Kralove, Faculty of Science, Department of Chemistry, Hradec Králové, Czech Republic; University Hospital Hradec Kralove, Biomedical Research Center, Hradec Králové, Czech Republic
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany.
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