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Estévez J, Pizarro L, Marsillach J, Furlong C, Sogorb MA, Richter R, Vilanova E. Inhibition with simultaneous spontaneous reactivation and aging of acetylcholinesterase by organophosphorus compounds: Demeton-S-methyl as a model. Chem Biol Interact 2024; 387:110789. [PMID: 37931869 DOI: 10.1016/j.cbi.2023.110789] [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: 08/08/2023] [Revised: 10/23/2023] [Accepted: 10/31/2023] [Indexed: 11/08/2023]
Abstract
The kinetic analysis of esterase inhibition by acylating compounds (organophosphorus, carbamates and sulfonylfluorides) sometimes cannot yield consistent results by fitting simple inhibition kinetic models to experimental data of complex systems. In this work kinetic data were obtained for demeton-S-methyl (DSM) with human acetylcholinesterase in two kinds of experiments: (a) time progressive inhibition with a range of concentrations, (b) progressive spontaneous reactivation starting with pre-inhibited enzyme. DSM is an organophosphorus compound used as pesticide and considered a model for studying the dermal exposure of nerve agents such as VX gas. A kinetic model equation was deduced with four different molecular phenomena occurring simultaneously: (1) inhibition; (2) spontaneous reactivation; (3) aging; and (4) ongoing inhibition (inhibition during the substrate reaction). A 3D fit of the model was applied to analyze the inhibition experimental data. The best-fitting model is compatible with a sensitive enzymatic entity. The second-order rate constant of inhibition (ki = 0.0422 μM-1 min-1), the spontaneous reactivation constant (ks = 0.0202 min-1) and the aging constant (kg = 0.0043 min-1) were simultaneously estimated. As an example for testing the model and approach, it was tested also in the presence of 5 % ethanol (conditions as previously used in the literature), the best fitting model is compatible with two apparent sensitive enzymatic entities (17 % and 83 %) and only one spontaneously reactivates and ages. The corresponding second-order rate constants of inhibition (ki = 0.0354 and 0.0119 μM-1 min-1) and the spontaneous reactivation and aging constants for the less sensitive component (kr = 0.0203 min-1 and kg = 0.0088 min-1) were estimated. The results were also consistent with a significant ongoing inhibition. These parameters were similar to those deduced in spontaneous reactivation experiments of the pre-inhibited samples with DSM in the absence or presence of ethanol. The two apparent components fit was interpreted by an equilibrium between ethanol-free and ethanol-bound enzyme. The consistency of results in inhibition and in spontaneous reactivation experiments was considered an internal validation of the methodology and the conclusions.
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Affiliation(s)
- Jorge Estévez
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, 03202, Elche, Alicante, Spain; Department of Medicine (Division of Medical Genetics) and Genome Sciences, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.
| | - Luis Pizarro
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, 03202, Elche, Alicante, Spain
| | - Judit Marsillach
- Department Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way NE, Suite 100, Seattle, WA, 98105, USA
| | - Clement Furlong
- Department of Medicine (Division of Medical Genetics) and Genome Sciences, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Miguel A Sogorb
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, 03202, Elche, Alicante, Spain
| | - Rebecca Richter
- Department of Medicine (Division of Medical Genetics) and Genome Sciences, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Eugenio Vilanova
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, 03202, Elche, Alicante, Spain
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Faria M, Fuertes I, Prats E, Abad JL, Padrós F, Gomez-Canela C, Casas J, Estevez J, Vilanova E, Piña B, Raldúa D. Analysis of the neurotoxic effects of neuropathic organophosphorus compounds in adult zebrafish. Sci Rep 2018; 8:4844. [PMID: 29555973 PMCID: PMC5859099 DOI: 10.1038/s41598-018-22977-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/05/2018] [Indexed: 12/13/2022] Open
Abstract
Inhibition and aging of neuropathy target esterase (NTE) by exposure to neuropathic organophosphorus compounds (OPs) can result in OP-induced delayed neuropathy (OPIDN). In the present study we aimed to build a model of OPIDN in adult zebrafish. First, inhibition and aging of zebrafish NTE activity were characterized in the brain by using the prototypic neuropathic compounds cresyl saligenin phosphate (CBDP) and diisopropylphosphorofluoridate (DFP). Our results show that, as in other animal models, zebrafish NTE is inhibited and aged by both neuropathic OPs. Then, a neuropathic concentration inhibiting NTE activity by at least 70% for at least 24 h was selected for each compound to analyze changes in phosphatidylcholines (PCs), lysophosphatidylcholines (LPCs) and glycerolphosphocholine (GPC) profiles. In spite to the strong inhibition of the NTE activity found for both compounds, only a mild increase in the LPCs level was found after 48 h of the exposure to DFP, and no effect were observed by CBDP. Moreover, histopathological evaluation and motor function outcome analyses failed to find any neurological abnormalities in the exposed fish. Thus, our results strongly suggest that zebrafish is not a suitable species for the development of an experimental model of human OPIDN.
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Affiliation(s)
- Melissa Faria
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, E-08034, Barcelona, Spain
| | - Inmaculada Fuertes
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, E-08034, Barcelona, Spain
| | - Eva Prats
- CID-CSIC, Jordi Girona 18, E-08034, Barcelona, Spain
| | - Jose Luis Abad
- Department of Biomedicinal Chemistry, Institute for Advanced Chemistry of Catalonia, (IQAC-CSIC), Jordi Girona 18, E-08034, Barcelona, Spain
| | - Francesc Padrós
- Fish Diseases Diagnostic Service, Facultat de Veterinaria Universitat Autònoma de Barcelona, 08190, Bellaterra (Cerdanyola del Vallès), Spain
| | - Cristian Gomez-Canela
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, E-08034, Barcelona, Spain
| | - Josefina Casas
- Department of Biomedicinal Chemistry, Institute for Advanced Chemistry of Catalonia, (IQAC-CSIC), Jordi Girona 18, E-08034, Barcelona, Spain
| | - Jorge Estevez
- Institute of Bioengineering, University "Miguel Hernandez" of Elche, Alicante, Spain
| | - Eugenio Vilanova
- Institute of Bioengineering, University "Miguel Hernandez" of Elche, Alicante, Spain
| | - Benjamin Piña
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, E-08034, Barcelona, Spain
| | - Demetrio Raldúa
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, E-08034, Barcelona, Spain.
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New mechanistic insights on the metabolic-disruptor role of chlorpyrifos in apoE mice: a focus on insulin- and leptin-signalling pathways. Arch Toxicol 2018; 92:1717-1728. [DOI: 10.1007/s00204-018-2174-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/31/2018] [Indexed: 01/08/2023]
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Esterases hydrolyze phenyl valerate activity as targets of organophosphorus compounds. Chem Biol Interact 2016; 259:358-367. [DOI: 10.1016/j.cbi.2016.04.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 03/30/2016] [Accepted: 04/12/2016] [Indexed: 12/24/2022]
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Ross MK, Pluta K, Bittles V, Borazjani A, Allen Crow J. Interaction of the serine hydrolase KIAA1363 with organophosphorus agents: Evaluation of potency and kinetics. Arch Biochem Biophys 2015; 590:72-81. [PMID: 26617293 DOI: 10.1016/j.abb.2015.11.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 11/03/2015] [Accepted: 11/20/2015] [Indexed: 11/19/2022]
Abstract
Oxons are bioactive metabolites of organophosphorus insecticides (OPs) that covalently inactivate serine hydrolases. KIAA1363 is one of the most abundant serine hydrolases in mouse brain. Although the physiological consequences related to the inhibition of KIAA1363 due to environmental exposures to OPs are poorly understood, the enzyme was previously shown to have a role in the detoxification of oxons. Here, we overexpressed human KIAA1363 and CES1 in COS7 cells and compared the potency of inhibition (IC50s, 15 min) of KIAA1363 and CES1 by chlorpyrifos oxon (CPO), paraoxon (PO), and methyl paraoxon (MPO). The order of potency was CPO > PO >> MPO for both enzymes. We also determined the bimolecular rate constants (kinact/Ki) for reactions of CPO and PO with KIAA1363 and CES1. KIAA1363 and CES1 were inactivated by CPO at comparable rates (4.4 × 10(6) s(-1) M(-1) and 6.7 × 10(6) s(-1) M(-1), respectively), whereas PO inactivated both enzymes at slower rates (0.4 × 10(6) s(-1) M(-1) and 1.5 × 10(6) s(-1) M(-1), respectively). Finally, the reactivation rate of KIAA1363 following inhibition by CPO was evaluated. Together, the results define the kinetics of inhibition of KIAA1363 by active metabolites of agrochemicals and indicate that KIAA1363 is highly sensitive to inhibition by these compounds.
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Affiliation(s)
- Matthew K Ross
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States; Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Kim Pluta
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States
| | - Victoria Bittles
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States
| | - Abdolsamad Borazjani
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States; Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States
| | - J Allen Crow
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States; Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States.
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Benabent M, Vilanova E, Mangas I, Sogorb MÁ, Estévez J. Interaction between substrates suggests a relationship between organophosphorus-sensitive phenylvalerate- and acetylcholine-hydrolyzing activities in chicken brain. Toxicol Lett 2014; 230:132-8. [PMID: 24576786 DOI: 10.1016/j.toxlet.2014.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 02/13/2014] [Accepted: 02/17/2014] [Indexed: 10/25/2022]
Abstract
Organophosphorus compounds (OPs) induce neurotoxic disorders through interactions with well-known target esterases, such as acetylcholinesterase and neuropathy target esterase (NTE). However, OPs interact with other esterases of unknown biological function. In soluble chicken brain fractions, three components of enzymatic phenylvalerate esterase activity (PVase) called Eα, Eβ and Eγ, have been kinetically discriminated. These components are studied in this work for the relationship with acetylcholine-hydrolyzing activity. When Eα PVase activity (resistant PVase activity to 1500 μM PMSF for 30 min) was tested with different acetylthiocholine concentrations, inhibition was observed. The best-fitting model to the data was the non-competitive inhibition model (Km=0.12, 0.22 mM, Ki=6.6, 7.6 mM). Resistant acetylthiocholine-hydrolyzing activity to 1500 μM PMSF was inhibited by phenylvalerate showing competitive inhibition (Km=0.09, 0.11 mM; Ki=1.7, 2.2 mM). Eβ PVase activity (resistant PVase activity to 25 μM mipafox for 30 min) was not affected by the presence of acetylthiocholine, while resistant acetylthiocholine-hydrolyzing activity to 25 μM mipafox showed competitive inhibition in the presence of phenylvalerate (Km=0.05, 0.06 mM; Ki=0.44, 0.58 mM). The interactions observed between the substrates of AChE and PVase suggest that part of PVase activity might be a protein with acetylthiocholine-hydrolyzing activity.
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Affiliation(s)
- Mónica Benabent
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain
| | - Eugenio Vilanova
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain
| | - Iris Mangas
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain
| | - Miguel Ángel Sogorb
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain
| | - Jorge Estévez
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain.
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Mangas I, Vilanova E, Benabent M, Estévez J. Separating esterase targets of organophosphorus compounds in the brain by preparative chromatography. Toxicol Lett 2014; 225:167-76. [DOI: 10.1016/j.toxlet.2013.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 12/03/2013] [Accepted: 12/06/2013] [Indexed: 10/25/2022]
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Genomic and phenotypic alterations of the neuronal-like cells derived from human embryonal carcinoma stem cells (NT2) caused by exposure to organophosphorus compounds paraoxon and mipafox. Int J Mol Sci 2014; 15:905-26. [PMID: 24413757 PMCID: PMC3907846 DOI: 10.3390/ijms15010905] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/08/2013] [Accepted: 12/17/2013] [Indexed: 12/31/2022] Open
Abstract
Historically, only few chemicals have been identified as neurodevelopmental toxicants, however, concern remains, and has recently increased, based upon the association between chemical exposures and increased developmental disorders. Diminution in motor speed and latency has been reported in preschool children from agricultural communities. Organophosphorus compounds (OPs) are pesticides due to their acute insecticidal effects mediated by the inhibition of acetylcholinesterase, although other esterases as neuropathy target esterase (NTE) can also be inhibited. Other neurological and neurodevelopmental toxic effects with unknown targets have been reported after chronic exposure to OPs in vivo. We studied the initial stages of retinoic acid acid-triggered differentiation of pluripotent cells towards neural progenitors derived from human embryonal carcinoma stem cells to determine if neuropathic OP, mipafox, and non-neuropathic OP, paraoxon, are able to alter differentiation of neural precursor cells in vitro. Exposure to 1 μM paraoxon (non-cytotoxic concentrations) altered the expression of different genes involved in signaling pathways related to chromatin assembly and nucleosome integrity. Conversely, exposure to 5 μM mipafox, a known inhibitor of NTE activity, showed no significant changes on gene expression. We conclude that 1 μM paraoxon could affect the initial stage of in vitro neurodifferentiation possibly due to a teratogenic effect, while the absence of transcriptional alterations by mipafox exposure did not allow us to conclude a possible effect on neurodifferentiation pathways at the tested concentration.
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Kinetic interactions of a neuropathy potentiator (phenylmethylsulfonyl fluoride) with the neuropathy target esterase and other membrane bound esterases. Arch Toxicol 2013; 88:355-66. [DOI: 10.1007/s00204-013-1135-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 09/12/2013] [Indexed: 10/26/2022]
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