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Hrabinova M, Pejchal J, Hepnarova V, Muckova L, Junova L, Opravil J, Zdarova Karasova J, Rozsypal T, Dlabkova A, Rehulkova H, Kucera T, Vecera Z, Caisberger F, Schmidt M, Soukup O, Jun D. A-series agent A-234: initial in vitro and in vivo characterization. Arch Toxicol 2024; 98:1135-1149. [PMID: 38446233 PMCID: PMC10944400 DOI: 10.1007/s00204-024-03689-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 01/23/2024] [Indexed: 03/07/2024]
Abstract
A-series agent A-234 belongs to a new generation of nerve agents. The poisoning of a former Russian spy Sergei Skripal and his daughter in Salisbury, England, in March 2018 led to the inclusion of A-234 and other A-series agents into the Chemical Weapons Convention. Even though five years have already passed, there is still very little information on its chemical properties, biological activities, and treatment options with established antidotes. In this article, we first assessed A-234 stability in neutral pH for subsequent experiments. Then, we determined its inhibitory potential towards human recombinant acetylcholinesterase (HssAChE; EC 3.1.1.7) and butyrylcholinesterase (HssBChE; EC 3.1.1.8), the ability of HI-6, obidoxime, pralidoxime, methoxime, and trimedoxime to reactivate inhibited cholinesterases (ChEs), its toxicity in rats and therapeutic effects of different antidotal approaches. Finally, we utilized molecular dynamics to explain our findings. The results of spontaneous A-234 hydrolysis showed a slow process with a reaction rate displaying a triphasic course during the first 72 h (the residual concentration 86.2%). A-234 was found to be a potent inhibitor of both human ChEs (HssAChE IC50 = 0.101 ± 0.003 µM and HssBChE IC50 = 0.036 ± 0.002 µM), whereas the five marketed oximes have negligible reactivation ability toward A-234-inhibited HssAChE and HssBChE. The acute toxicity of A-234 is comparable to that of VX and in the context of therapy, atropine and diazepam effectively mitigate A-234 lethality. Even though oxime administration may induce minor improvements, selected oximes (HI-6 and methoxime) do not reactivate ChEs in vivo. Molecular dynamics implies that all marketed oximes are weak nucleophiles, which may explain the failure to reactivate the A-234 phosphorus-serine oxygen bond characterized by low partial charge, in particular, HI-6 and trimedoxime oxime oxygen may not be able to effectively approach the A-234 phosphorus, while pralidoxime displayed low interaction energy. This study is the first to provide essential experimental preclinical data on the A-234 compound.
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Affiliation(s)
- Martina Hrabinova
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
| | - Jaroslav Pejchal
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
| | - Vendula Hepnarova
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic.
| | - Lubica Muckova
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
- University Hospital Hradec Kralove, Biomedical Research Centre, Sokolska 581, 500 05, Hradec Králové, Czech Republic
| | - Lucie Junova
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
- University Hospital Hradec Kralove, Biomedical Research Centre, Sokolska 581, 500 05, Hradec Králové, Czech Republic
| | - Jakub Opravil
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
| | - Jana Zdarova Karasova
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
- University Hospital Hradec Kralove, Biomedical Research Centre, Sokolska 581, 500 05, Hradec Králové, Czech Republic
| | - Tomas Rozsypal
- University of Defence, Nuclear, Biological, and Chemical Defence Institute, Vita Nejedleho 1, 68203, Vyskov, Czech Republic
| | - Alzbeta Dlabkova
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
| | - Helena Rehulkova
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
| | - Tomas Kucera
- University of Defence, Military Faculty of Medicine, Department of Military Medical Service Organization and Management, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
| | - Zbyněk Vecera
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic
| | - Filip Caisberger
- University Hospital Hradec Kralove, Department of Neurology, Sokolska 581, 500 05, Hradec Králové, Czech Republic
| | - Monika Schmidt
- University Hospital Hradec Kralove, Biomedical Research Centre, Sokolska 581, 500 05, Hradec Králové, Czech Republic
- University Hradec Kralove, Department of Chemistry, Faculty of Science, Rokitanskeho 62, 50003, Hradec Králové, Czech Republic
| | - Ondrej Soukup
- University Hospital Hradec Kralove, Biomedical Research Centre, Sokolska 581, 500 05, Hradec Králové, Czech Republic
| | - Daniel Jun
- University of Defence, Military Faculty of Medicine, Department of Toxicology and Military Pharmacy, Trebesska 1575, 500 01, Hradec Králové, Czech Republic.
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2
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Choudhir G, Sharma S, Hariprasad P. A combinatorial approach to screen structurally diverse acetylcholinesterase inhibitory plant secondary metabolites targeting Alzheimer's disease. J Biomol Struct Dyn 2022; 40:11705-11718. [PMID: 34351840 DOI: 10.1080/07391102.2021.1962408] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer's disease (AD) is a form of Dementia known to diminish the brain's function by perturbating its structural and functional components. Though cholinesterase inhibitors are widely used to treat AD, they are limited by numbers and side effects. Hence, present study aims to identify structurally diverse Acetylcholinesterase (AChE) inhibitory plant secondary metabolites (PSM) by employing high throughput screening and computational studies. AChE inhibitory activity was performed using 390 crude extracts from 63 plant parts belongs to 58 plants. The lowest IC50 value was recorded by acetone extract of Cyperus rotundus rhizome at 0.5 mg/ml, followed by methanol extract of Terminalia arjuna bark (0.95 mg/ml) and water extract Acacia catechu stem (0.95 mg/ml). A virtual library containing 487 PSM belongs to 18 plants found positive for AChE inhibition (IC50≤5 mg/ml) was prepared. Through ADMET analysis, 78 PSM fulfilling selected drug-likeness parameters were selected for further analysis. Molecular docking studies of selected PSM against AChE recorded a wide range of binding energy from -3.40 to -10.90 Kcal/mol. Further molecular dynamics simulation studies also recorded stabilized interactions of AChE-ligand complexes in the term of RMSD, RMSF, Rg, SASA, and hydrogen bond interaction. MMPBSA analysis revealed the binding energy of selected PSM ranging from -123.757 to -261.697 kJ/mol. Our study demonstrated the potential of 12 PSM (Sugiol, Margolone, 7-Hydroxy-3',4'-(Methylenedioxy) flavan, Beta-cyprone, Ethenone, Isomargolonone, Serpentine, Cryptolepine, Rotundone, Strictamin, Rotundenol and Nootkatone) as AChE inhibitors. Further in vitro and in vivo experimental evaluations with pure PSM could be beneficial for therapeutic uses.
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Affiliation(s)
- Gourav Choudhir
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi, India
| | - Satyawati Sharma
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi, India
| | - P Hariprasad
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi, India
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3
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Dolezal R. Accuracy and precision of binding free energy prediction for a tacrine related lead inhibitor of acetylcholinesterase with an arsenal of supercomputerized molecular modelling methods: a comparative study. J Biomol Struct Dyn 2022; 40:11291-11319. [PMID: 34323654 DOI: 10.1080/07391102.2021.1957716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Nowadays, advanced computational chemistry methods offer various strategies for revealing prospective hit structures in drug development essentially through accurate binding free energy predictions. After the era of molecular docking and quantitative structure-activity relationships, much interest has been lately oriented to perturbed molecular dynamic approaches like replica exchange with solute tempering and free energy perturbation (REST/FEP) and the potential of the mean force with adaptive biasing and accelerated weight histograms (PMF/AWH). Both of these receptor-based techniques can exploit exascale CPU&GPU supercomputers to achieve high throughput performance. In this fundamental study, we have compared the predictive power of a panel of supercomputerized molecular modelling methods to distinguish the major binding modes and the corresponding binding free energies of a promising tacrine related potential antialzheimerics in human acetylcholinesterase. The binding free energies were estimated using flexible molecular docking, molecular mechanics/generalized Born surface area/Poisson-Boltzmann surface area (MM/GBSA/PBSA), transmutation REST/FEP with 12 x 5 ns/λ windows, annihilation FEP with 20 x 5 ns/λ steps, PMF with weight histogram analysis method (WHAM) and 40 x 5 ns samples, and PMF/AWH with 10 x 100 ns replicas. Confrontation of the classical approaches such as canonical molecular dynamics and molecular docking with alchemical calculations and steered molecular dynamics enabled us to show how large errors in ΔG predictions can be expected if these in silico methods are employed in the elucidation of a common case of enzyme inhibition.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Rafael Dolezal
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic.,Biomedical Research Center, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
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4
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Gerlits O, Fajer M, Cheng X, Blumenthal DK, Radić Z, Kovalevsky A. Structural and dynamic effects of paraoxon binding to human acetylcholinesterase by X-ray crystallography and inelastic neutron scattering. Structure 2022; 30:1538-1549.e3. [PMID: 36265484 PMCID: PMC9637784 DOI: 10.1016/j.str.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/07/2022] [Accepted: 09/25/2022] [Indexed: 11/06/2022]
Abstract
Organophosphorus (OP) compounds, including nerve agents and some pesticides, covalently bind to the catalytic serine of human acetylcholinesterase (hAChE), thereby inhibiting acetylcholine hydrolysis necessary for efficient neurotransmission. Oxime antidotes can reactivate the OP-conjugated hAChE, but reactivation efficiency can be low for pesticides, such as paraoxon (POX). Understanding structural and dynamic determinants of OP inhibition and reactivation can provide insights to design improved reactivators. Here, X-ray structures of hAChE with unaged POX, with POX and oximes MMB4 and RS170B, and with MMB4 are reported. A significant conformational distortion of the acyl loop was observed upon POX binding, being partially restored to the native conformation by oximes. Neutron vibrational spectroscopy combined with molecular dynamics simulations showed that picosecond vibrational dynamics of the acyl loop soften in the ∼20-50 cm-1 frequency range. The acyl loop structural perturbations may be correlated with its picosecond vibrational dynamics to yield more comprehensive template for structure-based reactivator design.
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Affiliation(s)
- Oksana Gerlits
- Department of Natural Sciences, Tennessee Wesleyan University, Athens, TN 37303, USA
| | - Mikolai Fajer
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Xiaolin Cheng
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA
| | - Zoran Radić
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093-0657, USA.
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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5
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Lindgren C, Forsgren N, Hoster N, Akfur C, Artursson E, Edvinsson L, Svensson R, Worek F, Ekström F, Linusson A. Broad‐Spectrum Antidote Discovery by Untangling the Reactivation Mechanism of Nerve‐Agent‐Inhibited Acetylcholinesterase. Chemistry 2022; 28:e202200678. [PMID: 35420233 PMCID: PMC9400889 DOI: 10.1002/chem.202200678] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Indexed: 11/13/2022]
Abstract
Reactivators are vital for the treatment of organophosphorus nerve agent (OPNA) intoxication but new alternatives are needed due to their limited clinical applicability. The toxicity of OPNAs stems from covalent inhibition of the essential enzyme acetylcholinesterase (AChE), which reactivators relieve via a chemical reaction with the inactivated enzyme. Here, we present new strategies and tools for developing reactivators. We discover suitable inhibitor scaffolds by using an activity‐independent competition assay to study non‐covalent interactions with OPNA‐AChEs and transform these inhibitors into broad‐spectrum reactivators. Moreover, we identify determinants of reactivation efficiency by analysing reactivation and pre‐reactivation kinetics together with structural data. Our results show that new OPNA reactivators can be discovered rationally by exploiting detailed knowledge of the reactivation mechanism of OPNA‐inhibited AChE.
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Affiliation(s)
| | - Nina Forsgren
- CBRN Defense and Security Swedish Defense Research Agency 906 21 Umeå Sweden
| | - Norman Hoster
- Department of Chemistry Umeå University 901 87 Umeå Sweden
| | - Christine Akfur
- CBRN Defense and Security Swedish Defense Research Agency 906 21 Umeå Sweden
| | - Elisabet Artursson
- CBRN Defense and Security Swedish Defense Research Agency 906 21 Umeå Sweden
| | | | - Richard Svensson
- Biomedicinskt Centrum BMC Uppsala University 752 37 Uppsala Sweden
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology 80937 Munich Germany
| | - Fredrik Ekström
- CBRN Defense and Security Swedish Defense Research Agency 906 21 Umeå Sweden
| | - Anna Linusson
- Department of Chemistry Umeå University 901 87 Umeå Sweden
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6
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Gerlits O, Blakeley MP, Keen DA, Radić Z, Kovalevsky A. Room temperature crystallography of human acetylcholinesterase bound to a substrate analogue 4K-TMA: Towards a neutron structure. Curr Res Struct Biol 2021; 3:206-215. [PMID: 34541552 PMCID: PMC8435639 DOI: 10.1016/j.crstbi.2021.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/18/2021] [Accepted: 08/29/2021] [Indexed: 11/19/2022] Open
Abstract
Acetylcholinesterase (AChE) catalyzes hydrolysis of acetylcholine thereby terminating cholinergic nerve impulses for efficient neurotransmission. Human AChE (hAChE) is a target of nerve agent and pesticide organophosphorus compounds that covalently attach to the catalytic Ser203 residue. Reactivation of inhibited hAChE can be achieved with nucleophilic antidotes, such as oximes. Understanding structural and electrostatic (i.e. protonation states) determinants of the catalytic and reactivation processes is crucial to improve design of oxime reactivators. Here we report X-ray structures of hAChE conjugated with a reversible covalent inhibitor 4K-TMA (4K-TMA:hAChE) at 2.8 Å resolution and of 4K-TMA:hAChE conjugate with oxime reactivator methoxime, MMB4 (4K-TMA:hAChE:MMB4) at 2.6 Å resolution, both at physiologically relevant room temperature, as well as cryo-crystallographic structure of 4K-TMA:hAChE at 2.4 Å resolution. 4K-TMA acts as a substrate analogue reacting with the hydroxyl of Ser203 and generating a reversible tetrahedral hemiketal intermediate that closely resembles the first tetrahedral intermediate state during hAChE-catalyzed acetylcholine hydrolysis. Structural comparisons of room temperature with cryo-crystallographic structures of 4K-TMA:hAChE and published mAChE complexes with 4K-TMA, as well as the effect of MMB4 binding to the peripheral anionic site (PAS) of the 4K-TMA:hAChE complex, revealed only discrete, minor differences. The active center geometry of AChE, already highly evolved for the efficient catalysis, was thus indicative of only minor conformational adjustments to accommodate the tetrahedral intermediate in the hydrolysis of the neurotransmitter acetylcholine (ACh). To map protonation states in the hAChE active site gorge we collected 3.5 Å neutron diffraction data paving the way for obtaining higher resolution datasets that will be needed to determine locations of individual hydrogen atoms.
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Affiliation(s)
- Oksana Gerlits
- Department of Natural Sciences, Tennessee Wesleyan University, Athens, TN, 37303, USA
| | - Matthew P. Blakeley
- Large Scale Structures Group, Institut Laue–Langevin, 38000, Grenoble, France
| | - David A. Keen
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, UK
| | - Zoran Radić
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, 92093-0751, USA
- Corresponding author.
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Corresponding author.
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7
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Blumenthal DK, Cheng X, Fajer M, Ho KY, Rohrer J, Gerlits O, Taylor P, Juneja P, Kovalevsky A, Radić Z. Covalent inhibition of hAChE by organophosphates causes homodimer dissociation through long-range allosteric effects. J Biol Chem 2021; 297:101007. [PMID: 34324828 PMCID: PMC8384907 DOI: 10.1016/j.jbc.2021.101007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/20/2021] [Accepted: 07/23/2021] [Indexed: 11/26/2022] Open
Abstract
Acetylcholinesterase (EC 3.1.1.7), a key acetylcholine-hydrolyzing enzyme in cholinergic neurotransmission, is present in a variety of states in situ, including monomers, C-terminally disulfide-linked homodimers, homotetramers, and up to three tetramers covalently attached to structural subunits. Could oligomerization that ensures high local concentrations of catalytic sites necessary for efficient neurotransmission be affected by environmental factors? Using small-angle X-ray scattering (SAXS) and cryo-EM, we demonstrate that homodimerization of recombinant monomeric human acetylcholinesterase (hAChE) in solution occurs through a C-terminal four-helix bundle at micromolar concentrations. We show that diethylphosphorylation of the active serine in the catalytic gorge or isopropylmethylphosphonylation by the RP enantiomer of sarin promotes a 10-fold increase in homodimer dissociation. We also demonstrate the dissociation of organophosphate (OP)-conjugated dimers is reversed by structurally diverse oximes 2PAM, HI6, or RS194B, as demonstrated by SAXS of diethylphosphoryl-hAChE. However, binding of oximes to the native ligand-free hAChE, binding of high-affinity reversible ligands, or formation of an SP-sarin-hAChE conjugate had no effect on homodimerization. Dissociation monitored by time-resolved SAXS occurs in milliseconds, consistent with rates of hAChE covalent inhibition. OP-induced dissociation was not observed in the SAXS profiles of the double-mutant Y337A/F338A, where the active center gorge volume is larger than in wildtype hAChE. These observations suggest a key role of the tightly packed acyl pocket in allosterically triggered OP-induced dimer dissociation, with the potential for local reduction of acetylcholine-hydrolytic power in situ. Computational models predict allosteric correlated motions extending from the acyl pocket toward the four-helix bundle dimerization interface 25 Å away.
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Affiliation(s)
- Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA
| | - Xiaolin Cheng
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Mikolai Fajer
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Kwok-Yiu Ho
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, California, USA
| | - Jacqueline Rohrer
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, California, USA
| | - Oksana Gerlits
- Department of Natural Sciences, Tennessee Wesleyan University, Athens, Tennessee, USA
| | - Palmer Taylor
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, California, USA
| | - Puneet Juneja
- Cryo-EM Facility, Iowa State University, Ames, Iowa, USA
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Zoran Radić
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, California, USA.
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8
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Figueroa-Villar JD, Petronilho EC, Kuca K, Franca TCC. Review about Structure and Evaluation of Reactivators of Acetylcholinesterase Inhibited with Neurotoxic Organophosphorus Compounds. Curr Med Chem 2021; 28:1422-1442. [PMID: 32334495 DOI: 10.2174/0929867327666200425213215] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/08/2020] [Accepted: 04/01/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Neurotoxic chemical warfare agents can be classified as some of the most dangerous chemicals for humanity. The most effective of those agents are the Organophosphates (OPs) capable of restricting the enzyme Acetylcholinesterase (AChE), which in turn, controls the nerve impulse transmission. When AChE is inhibited by OPs, its reactivation can be usually performed through cationic oximes. However, until today, it has not been developed one universal defense agent, with complete effective reactivation activity for AChE inhibited by any of the many types of existing neurotoxic OPs. For this reason, before treating people intoxicated by an OP, it is necessary to determine the neurotoxic compound that was used for contamination, in order to select the most effective oxime. Unfortunately, this task usually requires a relatively long time, raising the possibility of death. Cationic oximes also display a limited capacity of permeating the Blood-Brain Barrier (BBB). This fact compromises their capacity to reactivating AChE inside the nervous system. METHODS We performed a comprehensive search on the data about OPs available on the scientific literature today in order to cover all the main drawbacks still faced in the research for the development of effective antidotes against those compounds. RESULTS Therefore, this review about neurotoxic OPs and the reactivation of AChE, provides insights for the new agents' development. The most expected defense agent is a molecule without toxicity and effective to reactivate AChE inhibited by all neurotoxic OPs. CONCLUSION To develop these new agents, the application of diverse scientific areas of research, especially theoretical procedures as computational science (computer simulation, docking and dynamics), organic synthesis, spectroscopic methodologies, biology, biochemical and biophysical information, medicinal chemistry, pharmacology and toxicology, is necessary.
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Affiliation(s)
- José Daniel Figueroa-Villar
- Medicinal Chemistry Group, Department of Chemical Engineering, Military Institute of Engineering, 22270- 090, Rio de Janeiro, Brazil
| | - Elaine C Petronilho
- Medicinal Chemistry Group, Department of Chemical Engineering, Military Institute of Engineering, 22270- 090, Rio de Janeiro, Brazil
| | - Kamil Kuca
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Králové 50003, Czech Republic
| | - Tanos C C Franca
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Králové 50003, Czech Republic
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9
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Molecular Modeling Studies on the Multistep Reactivation Process of Organophosphate-Inhibited Acetylcholinesterase and Butyrylcholinesterase. Biomolecules 2021; 11:biom11020169. [PMID: 33513955 PMCID: PMC7912477 DOI: 10.3390/biom11020169] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 12/17/2022] Open
Abstract
Poisoning with organophosphorus compounds used as pesticides or misused as chemical weapons remains a serious threat to human health and life. Their toxic effects result from irreversible blockade of the enzymes acetylcholinesterase and butyrylcholinesterase, which causes overstimulation of the cholinergic system and often leads to serious injury or death. Treatment of organophosphorus poisoning involves, among other strategies, the administration of oxime compounds. Oximes reactivate cholinesterases by breaking the covalent bond between the serine residue from the enzyme active site and the phosphorus atom of the organophosphorus compound. Although the general mechanism of reactivation has been known for years, the exact molecular aspects determining the efficiency and selectivity of individual oximes are still not clear. This hinders the development of new active compounds. In our research, using relatively simple and widely available molecular docking methods, we investigated the reactivation of acetyl- and butyrylcholinesterase blocked by sarin and tabun. For the selected oximes, their binding modes at each step of the reactivation process were identified. Amino acids essential for effective reactivation and those responsible for the selectivity of individual oximes against inhibited acetyl- and butyrylcholinesterase were identified. This research broadens the knowledge about cholinesterase reactivation and demonstrates the usefulness of molecular docking in the study of this process. The presented observations and methods can be used in the future to support the search for new effective reactivators.
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10
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Kneller DW, Galanie S, Phillips G, O'Neill HM, Coates L, Kovalevsky A. Malleability of the SARS-CoV-2 3CL M pro Active-Site Cavity Facilitates Binding of Clinical Antivirals. Structure 2020; 28:1313-1320.e3. [PMID: 33152262 PMCID: PMC7584437 DOI: 10.1016/j.str.2020.10.007] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/12/2020] [Accepted: 10/19/2020] [Indexed: 12/12/2022]
Abstract
The COVID-19 pandemic caused by SARS-CoV-2 requires rapid development of specific therapeutics and vaccines. The main protease of SARS-CoV-2, 3CL Mpro, is an established drug target for the design of inhibitors to stop the virus replication. Repurposing existing clinical drugs can offer a faster route to treatments. Here, we report on the binding mode and inhibition properties of several inhibitors using room temperature X-ray crystallography and in vitro enzyme kinetics. The enzyme active-site cavity reveals a high degree of malleability, allowing aldehyde leupeptin and hepatitis C clinical protease inhibitors (telaprevir, narlaprevir, and boceprevir) to bind and inhibit SARS-CoV-2 3CL Mpro. Narlaprevir, boceprevir, and telaprevir are low-micromolar inhibitors, whereas the binding affinity of leupeptin is substantially weaker. Repurposing hepatitis C clinical drugs as COVID-19 treatments may be a useful option to pursue. The observed malleability of the enzyme active-site cavity should be considered for the successful design of specific protease inhibitors.
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Affiliation(s)
- Daniel W Kneller
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA; National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
| | - Stephanie Galanie
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA; Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA
| | - Gwyndalyn Phillips
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA; National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
| | - Hugh M O'Neill
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA; National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
| | - Leighton Coates
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA; Second Target Station, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA.
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA; National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA.
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11
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Gorecki L, Gerlits O, Kong X, Cheng X, Blumenthal DK, Taylor P, Ballatore C, Kovalevsky A, Radić Z. Rational design, synthesis, and evaluation of uncharged, "smart" bis-oxime antidotes of organophosphate-inhibited human acetylcholinesterase. J Biol Chem 2020; 295:4079-4092. [PMID: 32019865 PMCID: PMC7105318 DOI: 10.1074/jbc.ra119.012400] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/03/2020] [Indexed: 01/05/2023] Open
Abstract
Organophosphate (OP) intoxications from nerve agent and OP pesticide exposures are managed with pyridinium aldoxime-based therapies whose success rates are currently limited. The pyridinium cation hampers uptake of OPs into the central nervous system (CNS). Furthermore, it frequently binds to aromatic residues of OP-inhibited acetylcholinesterase (AChE) in orientations that are nonproductive for AChE reactivation, and the structural diversity of OPs impedes efficient reactivation. Improvements of OP antidotes need to include much better access of AChE reactivators to the CNS and optimized orientation of the antidotes' nucleophile within the AChE active-center gorge. On the basis of X-ray structures of a CNS-penetrating reactivator, monoxime RS194B, reversibly bound to native and venomous agent X (VX)-inhibited human AChE, here we created seven uncharged acetamido bis-oximes as candidate antidotes. Both oxime groups in these bis-oximes were attached to the same central, saturated heterocyclic core. Diverse protonation of the heterocyclic amines and oxime groups of the bis-oximes resulted in equilibration among up to 16 distinct ionization forms, including uncharged forms capable of diffusing into the CNS and multiple zwitterionic forms optimal for reactivation reactions. Conformationally diverse zwitterions that could act as structural antidote variants significantly improved in vitro reactivation of diverse OP-human AChE conjugates. Oxime group reorientation of one of the bis-oximes, forcing it to point into the active center for reactivation, was confirmed by X-ray structural analysis. Our findings provide detailed structure-activity properties of several CNS-directed, uncharged aliphatic bis-oximes holding promise for use as protonation-dependent, conformationally adaptive, "smart" accelerated antidotes against OP toxicity.
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Affiliation(s)
- Lukas Gorecki
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0751
| | - Oksana Gerlits
- Bredesen Center, University of Tennessee, Knoxville, Tennessee 37996
| | - Xiaotian Kong
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Ohio State University, Columbus, Ohio 43210
| | - Xiaolin Cheng
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Ohio State University, Columbus, Ohio 43210
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112
| | - Palmer Taylor
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0751
| | - Carlo Ballatore
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0751
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Zoran Radić
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0751.
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12
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Semenov VE, Zueva IV, Lushchekina SV, Lenina OA, Gubaidullina LM, Saifina LF, Shulaeva MM, Kayumova RM, Saifina AF, Gubaidullin AT, Kondrashova SA, Latypov SK, Masson P, Petrov KA. 6-Methyluracil derivatives as peripheral site ligand-hydroxamic acid conjugates: Reactivation for paraoxon-inhibited acetylcholinesterase. Eur J Med Chem 2019; 185:111787. [PMID: 31675511 DOI: 10.1016/j.ejmech.2019.111787] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 10/07/2019] [Accepted: 10/11/2019] [Indexed: 12/19/2022]
Abstract
New uncharged conjugates of 6-methyluracil derivatives with imidazole-2-aldoxime and 1,2,4-triazole-3-hydroxamic acid units were synthesized and studied as reactivators of organophosphate-inhibited cholinesterase. Using paraoxon (POX) as a model organophosphate, it was shown that 6-methyluracil derivatives linked with hydroxamic acid are able to reactivate POX-inhibited human acetylcholinesterase (AChE) in vitro. The reactivating efficacy of one compound (5b) is lower than that of pyridinium-2-aldoxime (2-PAM). Meanwhile, unlike 2-PAM, in vivo study showed that the lead compound 5b is able: (1) to reactivate POX-inhibited AChE in the brain; (2) to decrease death of neurons and, (3) to prevent memory impairment in rat model of POX-induced neurodegeneration.
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Affiliation(s)
- Vyacheslav E Semenov
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation.
| | - Irina V Zueva
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Sofya V Lushchekina
- N.M. Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, Kosygina str., 4, Moscow, 119334, Russian Federation
| | - Oksana A Lenina
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Lilya M Gubaidullina
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Lilya F Saifina
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Marina M Shulaeva
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Ramilya M Kayumova
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Alina F Saifina
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Aidar T Gubaidullin
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Svetlana A Kondrashova
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Shamil K Latypov
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
| | - Patrick Masson
- Kazan Federal University, Kremlyovskaya str., 18, Kazan, 420008, Russian Federation
| | - Konstantin A Petrov
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, 420088, Russian Federation
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