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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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Prchalova E, Kohoutova Z, Knittelova K, Malinak D, Musilek K. Strategies for enhanced bioavailability of oxime reactivators in the central nervous system. Arch Toxicol 2023; 97:2839-2860. [PMID: 37642747 DOI: 10.1007/s00204-023-03587-0] [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: 03/10/2023] [Accepted: 08/10/2023] [Indexed: 08/31/2023]
Abstract
Oxime reactivators of acetylcholinesterase are commonly used to treat highly toxic organophosphate poisoning. They are effective nucleophiles that can restore the catalytic activity of acetylcholinesterase; however, their main limitation is the difficulty in crossing the blood-brain barrier (BBB) because of their strongly hydrophilic nature. Various approaches to overcome this limitation and enhance the bioavailability of oxime reactivators in the CNS have been evaluated; these include structural modifications, conjugation with molecules that have transporters in the BBB, bypassing the BBB through intranasal delivery, and inhibition of BBB efflux transporters. A promising approach is the use of nanoparticles (NPs) as the delivery systems. Studies using mesoporous silica nanomaterials, poly (L-lysine)-graft-poly(ethylene oxide) NPs, metallic organic frameworks, poly(lactic-co-glycolic acid) NPs, human serum albumin NPs, liposomes, solid lipid NPs, and cucurbiturils, have shown promising results. Some NPs are considered as nanoreactors for organophosphate detoxification; these combine bioscavengers with encapsulated oximes. This study provides an overview and critical discussion of the strategies used to enhance the bioavailability of oxime reactivators in the central nervous system.
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Affiliation(s)
- Eliska Prchalova
- Faculty of Science, Department of Chemistry, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic
| | - Zuzana Kohoutova
- Faculty of Science, Department of Chemistry, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic
| | - Karolina Knittelova
- Faculty of Science, Department of Chemistry, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic
| | - David Malinak
- Faculty of Science, Department of Chemistry, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic.
- Biomedical Research Centre, University Hospital in Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.
| | - Kamil Musilek
- Faculty of Science, Department of Chemistry, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic.
- Biomedical Research Centre, University Hospital in Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.
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Solé M, Figueres E, Mañanós E, Rojo-Solís C, García-Párraga D. Characterisation of plasmatic B-esterases in bottlenose dolphins (Tursiops truncatus) and their potential as biomarkers of xenobiotic chemical exposures. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 313:120149. [PMID: 36115493 DOI: 10.1016/j.envpol.2022.120149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/23/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
A total of 164 blood samples from 16 clinically healthy bottlenose dolphins (Tursiops truncatus), were obtained from an aquarium in Spain between 2019 and 2020, as part of their preventive medicine protocol. In addition to conventional haematological and biochemical analyses, plasmatic B-esterase activities were characterised to determine the potential application of such analyses in wild counterparts. The hydrolysis rates for the substrates of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and carboxylesterase (CE) activity in plasma were measured, the last using two commercial substrates, p-nitrophenyl acetate (pNPA) and p-nitrophenyl butyrate (pNPB). Activity rates (mean ± SEM in nmol/min/mL plasma) were (in descending order): AChE (125.6 ± 3.8), pNPB-CE (65.0 ± 2.2), pNPA-CE (49.7 ± 1.1) and BuChE (12.8 ± 1.3). These values for dolphins are reported in here for the first time in this species. Additionally, the in vitro sensitivity of two B-esterases (AChE and pNPB-CE) to chemicals of environmental concern was determined, and the protective role of plasmatic albumin assessed. Out of the B-esterases measured in plasma of dolphin, AChE activity was more responsive in vitro to pesticides, while CEs had a low response to plastic additives, likely due to the protective presence of albumin. However, the clear in vitro interaction of these environmental chemicals with purified AChE from electric eels and recombinant human hCEs (hCE1 and hCE2) and albumin, predicts their impact in other tissues that require in vivo validation. A relationship between esterase-like activities and health parameters in terrestrial mammals has already been established. Thus, B-esterase measures could be easily included in marine mammal health assessment protocols for dolphins as well, once the relationship between these measures and the animal's fitness has been established.
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Affiliation(s)
- M Solé
- Institut de Ciències del Mar, CSIC, Psg. Marítim de La Barceloneta 37-49, 08003, Barcelona, Spain.
| | - E Figueres
- Institut de Ciències del Mar, CSIC, Psg. Marítim de La Barceloneta 37-49, 08003, Barcelona, Spain
| | - E Mañanós
- Institute of Aquaculture Torre La Sal (IATS),-CSIC, 12595, Cabanes, Castellón, Spain
| | - C Rojo-Solís
- Veterinary Services, Oceanogràfic, Ciudad de Las Artes y Las Ciencias, C/Eduardo Primo Yúfera (Científic) 1B, 46013, València, Spain
| | - D García-Párraga
- Veterinary Services, Oceanogràfic, Ciudad de Las Artes y Las Ciencias, C/Eduardo Primo Yúfera (Científic) 1B, 46013, València, Spain
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Talley TT, Chao CK, Berkman CE, Richardson RJ, Thompson CM. Inhibition of Acetylcholinesterases by Stereoisomeric Organophosphorus Compounds Containing Both Thioester and p-Nitrophenyl Leaving Groups. Chem Res Toxicol 2020; 33:2455-2466. [PMID: 32833441 DOI: 10.1021/acs.chemrestox.0c00236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Studies with acetylcholinesterase (AChE) inhibited by organophosphorus (OP) compounds with two chiral centers can serve as models or surrogates for understanding the rate, orientation, and postinhibitory mechanisms by the nerve agent soman that possesses dual phosphorus and carbon chiral centers. In the current approach, stereoisomers of O-methyl, [S-(succinic acid, diethyl ester), O-(4-nitrophenyl) phosphorothiolate (MSNPs) were synthesized, and the inhibition, reactivation, and aging mechanisms were studied with electric eel AChE (eeAChE) and recombinant mouse brain AChE (rmAChE). The MSNP RPRC isomer was the strongest inhibitor of both eeAChE and rmAChE at 8- and 24-fold greater potency, respectively, than the weakest SPSC isomer. eeAChE inhibited by the RPRC- or RPSC-MSNP isomer underwent spontaneous reactivation ∼10- to 20-fold faster than the enzyme inhibited by SPRC- and SPSC-MSNP, and only 4% spontaneous reactivation was observed from the SPRC-eeAChE adduct. Using 2-pyridine aldoxime methiodide (2-PAM) or trimedoxime (TMB-4), eeAChE inhibited by RPRC- or SPRC-MSNP reactivated up to 90% and 3- to 4-fold faster than eeAChE inhibited by the RPSC- or SPSC-MSNP isomer. Spontaneous reactivation rates for rmAChE were 1.5- to 10-fold higher following inhibition by RPSC- and SPSC-MSNPs than inhibition by either RC isomer, a trend opposite to that found for eeAChE. Oxime reactivation of rmAChE following inhibition by RPRC- and SPRC-MSNPs was 2.5- to 5-fold faster than inhibition by RPSC- or SPSC-MSNPs. Due to structural similarities, MSNPs that phosphylate AChE with the loss of the p-nitrophenoxy (PNP) group form identical, nonreactivatable adducts to those formed from SP-isomalathion; however, all the MSNP isomers inhibited AChE to form adducts that reactivated. Thus, MSNPs inactivate AChE via the ejection of either PNP or thiosuccinyl groups to form a combination of reactivatable and nonreactivatable adducts, and this differs from the mechanism of AChE inhibition by isomalathion.
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Affiliation(s)
- Todd T Talley
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, Montana 59812, United States
| | - Chih-Kai Chao
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, Montana 59812, United States
| | - Clifford E Berkman
- Department of Chemistry and Biochemistry, Washington State University, Pullman, Washington 99164, United States
| | - Rudy J Richardson
- Departments of Environmental Health Sciences and Neurology, University of Michigan, Ann Arbor, Michigan 48109, United States.,Center of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Charles M Thompson
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, Montana 59812, United States
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Estévez J, Benabent M, Selva V, Mangas I, Sogorb MÁ, Del Rio E, Vilanova E. Cholinesterase and phenyl valerate-esterase activities sensitive to organophosphorus compounds in membranes of chicken brain. Toxicology 2018; 410:73-82. [PMID: 30176330 DOI: 10.1016/j.tox.2018.08.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/31/2018] [Accepted: 08/29/2018] [Indexed: 11/26/2022]
Abstract
Some effects of organophosphorus compounds (OPs) esters cannot be explained by action on currently recognized targets acetylcholinesterase or neuropathy target esterase (NTE). In previous studies, in membrane chicken brain fractions, four components (EPα, EPβ, EPγ and EPδ) of phenyl valerate esterase activity (PVase) had been kinetically discriminated combining data of several inhibitors (paraoxon, mipafox, PMSF). EPγ is belonging to NTE. The relationship of PVase components and acetylcholine-hydrolyzing activity (cholinesterase activity) is studied herein. Only EPα PVase activity showed inhibition in the presence of acetylthiocholine, similarly to a non-competitive model. EPα is highly sensitive to mipafox and paraoxon, but is resistant to PMSF, and is spontaneously reactivated when inhibited with paraoxon. In this papers we shows that cholinesterase activities showed inhibition kinetic by PV, which does not fit with a competitive inhibition model when tested for the same experimental conditions used to discriminate the PVase components. Four enzymatic components (CP1, CP2, CP3 and CP4) were discriminated in cholinesterase activity in the membrane fraction according to their sensitivity to irreversible inhibitors mipafox, paraoxon, PMSF and iso-OMPA. Components CP1 and CP2 could be related to EPα as they showed interactions between substrates and similar inhibitory kinetic properties to the tested inhibitors.
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Affiliation(s)
- Jorge Estévez
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain
| | - Mónica Benabent
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain
| | - Verónica Selva
- 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
| | - Eva Del Rio
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain
| | - Eugenio Vilanova
- University "Miguel Hernandez", Institute of Bioengineering, Unit of Toxicology, Elche, Spain.
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6
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Sanchez-Hernandez JC, Ríos JM, Attademo AM. Response of digestive enzymes and esterases of ecotoxicological concern in earthworms exposed to chlorpyrifos-treated soils. ECOTOXICOLOGY (LONDON, ENGLAND) 2018; 27:890-899. [PMID: 29497918 DOI: 10.1007/s10646-018-1914-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/09/2018] [Indexed: 06/08/2023]
Abstract
Assessment of organophosphorus (OP) pesticide exposure in non-target organisms rarely involves non-neural molecular targets. Here we performed a 30-d microcosm experiment with Lumbricus terrestris to determine whether the activity of digestive enzymes (phosphatase, β-glucosidase, carboxylesterase and lipase) was sensitive to chlorpyrifos (5 mg kg-1 wet soil). Likewise, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were measured in the wall muscle and gastrointestinal tissues as indicators of OP exposure. Chlorpyrifos inhibited the acid phosphatase (34% of controls), carboxylesterase (25.6%) and lipase activities (31%) in the gastrointestinal content. However, in the gastrointestinal tissue, only the carboxylesterase and lipase activities were significantly depressed (42-67% carboxylesterase inhibition in the foregut and crop/gizzard, and 15% lipase inhibition in the foregut). Chlorpyrifos inhibited the activity of both cholinesterases in the gastrointestinal tissues, whereas the AChE activity was affected in the wall muscle. These results suggested chlorpyrifos was widely distributed throughout the earthworm body after 30 d of incubation. Interestingly, we found muscle carboxylesterase activity strongly inhibited (92% of control) compared with that detected in the gastrointestinal tissues of the same OP-exposed individuals. This finding was explained by the occurrence of pesticide-resistant esterases in the gastrointestinal tissues, which were evidenced by zymography. Our results suggest that digestive processes of L. terrestris may be altered by chlorpyrifos, as a consequence of the inhibitory action of the insecticide on some digestive enzymes.
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Affiliation(s)
- Juan C Sanchez-Hernandez
- Laboratory of Ecotoxicology, Faculty of Environmental Science and Biochemistry, University of Castilla-La Mancha, 45071, Toledo, Spain.
| | - Juan Manuel Ríos
- Laboratorio de Química Ambiental, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (IANIGLA)-CONICET, P.O. Box 131, ZC5500, Mendoza, Argentina
| | - Andrés M Attademo
- Laboratorio de Ecotoxicología, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (FBCB-UNL-CONICET), Paraje El Pozo s/n, 3000, Santa Fe, Argentina
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7
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Catalytic bioscavengers as countermeasures against organophosphate nerve agents. Chem Biol Interact 2018; 292:50-64. [DOI: 10.1016/j.cbi.2018.07.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 07/04/2018] [Accepted: 07/06/2018] [Indexed: 12/30/2022]
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8
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Hydrolyzing activities of phenyl valerate sensitive to organophosphorus compounds paraoxon and mipafox in human neuroblastoma SH-SY5Y cells. Toxicology 2018; 406-407:123-128. [PMID: 30118792 DOI: 10.1016/j.tox.2018.07.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 07/21/2018] [Accepted: 07/24/2018] [Indexed: 11/22/2022]
Abstract
The molecular targets of best known neurotoxic effects associated to acute exposure to organophosphorus compounds (OPs) are serine esterases located in the nervous system, although there are other less known neurotoxic adverse effects associated with chronic exposure to OPs whose toxicity targets are still not identified. In this work we studied sensitivity to the non-neuropathic OP paraoxon and to the neuropathic OP mipafox of phenyl valerate esterases (PVases) in intact and lysed human neuroblastoma SH-SY5Y cells. The main objective was to discriminate different unknown pools of esterases that might be potential targets of chronic effects from those esterases already known and recognized as targets to these acute neurotoxicity effects. Two components of PVases of different sensitivities were discriminated for paraoxon in both intact and lysed cells; while the two components inhibitable by mipafox were found only for intact cells. A completely resistant component to paraoxon of around 30% was found in both intact and lysed cells; while a component of slightly lower amplitude (around 20%) completely resistant to mipafox was also found for both preparations (intact and lysed cells). The comparison of the results between the intact cells and the lysed cells suggests that the plasma membrane could act as a barrier that reduced the bioavailability of mipafox to PVases. This would imply that the discrimination of the different esterases should be made in lysed cells. However, those studies which aim to determine the physiological role of these esterases should be necessarily conducted in intact cultured cells.
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9
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He HL, Lee YE, Chang MT, Shiue YL, Chang SL, Chen TJ, Chiu CT. AMACR overexpression acts as a negative prognostic factor in oral squamous cell carcinoma. Int J Med Sci 2018; 15:638-644. [PMID: 29725255 PMCID: PMC5930466 DOI: 10.7150/ijms.23291] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 03/02/2018] [Indexed: 12/28/2022] Open
Abstract
Background: Alpha-methylacyl-CoA racemase (AMACR) is a key enzyme responsible for the metabolism of branched-chain fatty acids. It has been found to be an important prognostic factor in numerous types of cancers. This study was aimed to investigate the expression of AMACR and its prognostic significance in patients with oral squamous cell carcinoma (SCC). Methods: Analysis of publicly available microarray data of oral SCC revealed that AMACR was significantly upregulated in tumor tissue compared with normal mucosa. We further assessed the protein expression of AMACR in 164 patients with oral SCC by immunohistochemistry. The prognostic impact of AMACR expression and its association with various clinicopathological parameters were statistically analyzed. Results: AMACR overexpression was significantly associated with advanced tumor status (P=0.001), advanced nodal status (P=0.036), increased vascular invasion (P=0.026) and increased perineural invasion (P=0.004). Patients with high expression level of AMACR had significantly worse disease-specific survival (DSS), distant metastasis-free survival (DMFS) and local recurrence-free survival (LRFS) (all P<0.0001). In multivariate analysis, AMACR overexpression was also an independent negative prognostic factor for DSS (hazard ratio [HR]: 4.410, 95% confidence interval [CI]: 2.285-8.511, P<0.001), DMFS (HR: 5.157, 95% CI: 2.756-9.651, P<0.001) and LRFS (HR: 4.462, 95% CI: 2.429-8.198, P<0.001). Conclusions: High expression of AMACR was not only a key adverse prognostic factor but also a potential therapeutic target in oral SCC.
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Affiliation(s)
- Hong-Lin He
- Department of Pathology, Chi Mei Medical Center, Tainan, Taiwan.,Department of Pathology, E-DA Hospital, I-Shou University, Kaohsiung, Taiwan
| | - Ying-En Lee
- Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.,Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Min-Te Chang
- Department of Oral and Maxillofacial Surgery, Chi Mei Medical Center, Tainan, Taiwan
| | - Yow-Ling Shiue
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Shih-Lun Chang
- Department of Otolaryngology, Chi Mei Medical Center, Yongkang District, Tainan City, Taiwan.,Department of Optometry, Chung Hwa University of Medical Technology, Tainan, Taiwan
| | - Tzu-Ju Chen
- Department of Pathology, Chi Mei Medical Center, Tainan, Taiwan.,Department of Optometry, Chung Hwa University of Medical Technology, Tainan, Taiwan
| | - Chang-Ta Chiu
- Department of Oral & Maxillofacial Surgery, An Nan Hospital, China Medical University, Tainan, Taiwan
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10
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In Vitro Evaluation of Serine Hydrolase Inhibitors. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2018. [DOI: 10.1007/7653_2018_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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11
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New insights on molecular interactions of organophosphorus pesticides with esterases. Toxicology 2017; 376:30-43. [DOI: 10.1016/j.tox.2016.06.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 05/25/2016] [Accepted: 06/10/2016] [Indexed: 01/01/2023]
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12
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Use of V agents and V-analogue compounds to probe the active site of atypical butyrylcholinesterase from Oryzias latipes. Chem Biol Interact 2016; 259:182-186. [PMID: 27000540 DOI: 10.1016/j.cbi.2016.03.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/03/2016] [Accepted: 03/15/2016] [Indexed: 11/22/2022]
Abstract
The atypical butyrylcholinesterase (aBuChE) from Oryzias latipes shares approximately 65% sequence similarity to both acetylcholinesterase and butyrylcholinesterase and was studied for its capacity to spontaneously reactivate following inhibition by organophosphorus nerve agents. Like other cholinesterases, aBuChE was inhibited by all G- and V-type nerve agents. Interestingly, aBuChE was able to undergo spontaneous reactivation after inhibition with VR (t1/2 = 5.5 ± 0.2 h). Mass spectrometry of aBuChE after VR inhibition confirmed the presence of a covalently bound adduct of the size expected for non-aged VR on the peptide containing the active site serine. To understand the effect of substrate volume on rates of reactivation, the capacity of aBuChE to bind and spontaneously reactivate after inhibition with five V-agent analogues was examined. No appreciable reactivation was detected for enzyme inhibited by V2 (VX with O-isopropyl on retained group), V4 (VX with N-diethyl leaving group termination), or V5 (VX with N-dimethyl leaving group termination). Minimal reactivation was detected with V1 (VX with O-propyl on retained group). Conversely, spontaneous reactivation was observed when aBuChE was inhibited by V3 (VX with O-isobutyl on retained group; t1/2 = 6.3 ± 0.4 h). The data suggest that the ability of aBuChE to spontaneously reactivate after inhibition by V-agent analogues is related to the structure of the retained group. These results provide structural information that may shed light on the design of improved small molecule reactivators of nerve agent-inhibited acetylcholinesterase or butyrylcholinesterase, and further suggest that re-engineering the active site of a cholinesterase could result in enzymes with clinically relevant rates of nerve agent hydrolysis.
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13
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Makhaeva GF, Rudakova EV, Serebryakova OG, Aksinenko AY, Lushchekina SV, Bachurin SO, Richardson RJ. Esterase profiles of organophosphorus compounds in vitro predict their behavior in vivo. Chem Biol Interact 2016; 259:332-342. [DOI: 10.1016/j.cbi.2016.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 04/26/2016] [Accepted: 05/02/2016] [Indexed: 10/21/2022]
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14
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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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15
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Acetylcholine-hydrolyzing activities in soluble brain fraction: Characterization with reversible and irreversible inhibitors. Chem Biol Interact 2016; 259:374-381. [PMID: 27507601 DOI: 10.1016/j.cbi.2016.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/05/2016] [Accepted: 08/05/2016] [Indexed: 11/22/2022]
Abstract
Some effects of organophosphorus compounds (OPs) esters cannot be explained through actions on currently recognized targets acetylcholinesterase or neuropathy target esterase (NTE). In soluble chicken brain fraction, three components (Eα, Eβ and Eγ) of pheny lvalerate esterase activity (PVase) were kinetically discriminated and their relationship with acetylcholine-hydrolyzing activity (cholinesterase activity) were studied in previous works. In this work, four enzymatic components (CS1, CS2, CS3 and CS4) of cholinesterase activity have been discriminated in soluble fraction, according to their sensitivity to irreversible inhibitors mipafox, paraoxon, PMSF and iso-OMPA and to reversible inhibitors ethopropazine and BW284C51. Cholinesterase component CS1 can be related to the Eα component of PVase activity and identified as butyrylcholinesterase (BuChE). No association and similarities can be stablished among the other PVase component (Eβ and Eγ) with the other cholinesterase components (CS2, CS3, CS4). The kinetic analysis has allowed us to stablish a method for discriminating the enzymatic component based on a simple test with two inhibitors. It can be used as biomarker in toxicological studies and for monitoring these cholinesterase components during isolation and molecular identification processes, which will allow OP toxicity to be understood by a multi-target approach.
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Ülker S, Placidi C, Point V, Gadenne B, Serveau-Avesque C, Canaan S, Carrière F, Cavalier JF. New lipase assay using Pomegranate oil coating in microtiter plates. Biochimie 2016; 120:110-8. [DOI: 10.1016/j.biochi.2015.09.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 09/01/2015] [Indexed: 10/23/2022]
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Sanchez-Hernandez JC, Notario del Pino J, Domínguez J. Earthworm-induced carboxylesterase activity in soil: Assessing the potential for detoxification and monitoring organophosphorus pesticides. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 122:303-312. [PMID: 26300118 DOI: 10.1016/j.ecoenv.2015.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 08/11/2015] [Accepted: 08/12/2015] [Indexed: 06/04/2023]
Abstract
Soil enzyme activities are attracting widespread interest due to its potential use in contaminant breakdown, and as indicators of soil deterioration. However, given the multiple environmental and methodological factors affecting their activity levels, assessment of soil pollution using these biochemical endpoints is still complex. Taking advantage of the well-known stimulatory effect of earthworms on soil microbes, and their associated enzyme activities, we explored some toxicological features of carboxylesterases (CbEs) in soils inoculated with Lumbricus terrestris. A microplate-scale spectrophotometric assay using soil-water suspensions was first optimized, in which kinetic assay parameters (Km, Vmax, dilution of soil homogenate, and duration of soil homogenization) were established for further CbE determinations. Optimal conditions included a soil-to-water ratio of 1:50 (w/v), 30-min of shaking, and 2.5mM of substrate concentration. As expected, CbE activity increased significantly in soils treated with L. terrestris. This bioturbed soil was used for exploring the role of CbE activity as a bioscavenger for organophosphorus (OP) pesticides. Soil treated with two formulations of chlorpyrifos revealed that CbE activity was a significant molecular sink for this pesticide, reducing its impact on soil microbial activity as shown by the unchanged dehydrogenase activity. Dose-dependent curves were adjusted to an exponential kinetic model, and the median ecological dose (ED50) for both pesticide formulations was calculated. ED50 values decreased as the time of pesticide exposure increased (14 d-ED50s=20.4-26.7 mg kg(-1), and 28 d-ED50s=1.8-2.3 mg kg(-1)), which suggested that chlorpyrifos was progressively transformed into its highly toxic metabolite chlorpyrifos-oxon, but simultaneously was inactivated by CbEs. These results were confirmed by in vitro assays that showed chlorpyrifos-oxon was a more potent CbE inhibitor (IC50=35.5-4.67 nM) than chlorpyrifos (0.41-0.84 μM). The results showed that earthworm-induced CbE activity is an efficient bioscavengers for OP pesticides, acting as a soil safeguarding system. Moreover, the simple dose-response curves against OP exposure suggest that this enzyme--combined with other enzyme activities (e.g., dehydrogenase)--may be a suitable biomarker of pesticide exposure.
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Affiliation(s)
- Juan C Sanchez-Hernandez
- Ecotoxicology Lab, Fac. Environmental Science and Biochemistry, University of Castilla-La Mancha, Toledo, Spain.
| | - J Notario del Pino
- Department of Animal Biology, Soil Science and Geology, University of La Laguna, Canary Islands, Spain
| | - Jorge Domínguez
- Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, 36310 Vigo, Spain
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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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Reiter G, Müller S, Koller M, Thiermann H, Worek F. In vitro toxicokinetic studies of cyclosarin: Molecular mechanisms of elimination. Toxicol Lett 2014; 227:1-11. [DOI: 10.1016/j.toxlet.2014.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 11/17/2022]
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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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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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Lloyd MD, Yevglevskis M, Lee GL, Wood PJ, Threadgill MD, Woodman TJ. α-Methylacyl-CoA racemase (AMACR): Metabolic enzyme, drug metabolizer and cancer marker P504S. Prog Lipid Res 2013; 52:220-30. [DOI: 10.1016/j.plipres.2013.01.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 10/27/2022]
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Makhaeva GF, Radchenko EV, Palyulin VA, Rudakova EV, Aksinenko AY, Sokolov VB, Zefirov NS, Richardson RJ. Organophosphorus compound esterase profiles as predictors of therapeutic and toxic effects. Chem Biol Interact 2013; 203:231-7. [DOI: 10.1016/j.cbi.2012.10.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/07/2012] [Accepted: 10/09/2012] [Indexed: 11/29/2022]
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Liyasova MS, Schopfer LM, Kodani S, Lantz SR, Casida JE, Lockridge O. Newly Observed Spontaneous Activation of Ethephon as a Butyrylcholinesterase Inhibitor. Chem Res Toxicol 2013; 26:422-31. [DOI: 10.1021/tx300501n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mariya S. Liyasova
- Department of Environmental, Agricultural & Occupational Health and Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, United States
| | - Lawrence M. Schopfer
- Department of Environmental, Agricultural & Occupational Health and Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, United States
| | - Sean Kodani
- Environmental Chemistry and
Toxicology Laboratory, Department of Environmental Science, Policy
and Management, University of California, Berkeley, California 94720-3112, United States
| | - Stephen R. Lantz
- Environmental Chemistry and
Toxicology Laboratory, Department of Environmental Science, Policy
and Management, University of California, Berkeley, California 94720-3112, United States
| | - John E. Casida
- Environmental Chemistry and
Toxicology Laboratory, Department of Environmental Science, Policy
and Management, University of California, Berkeley, California 94720-3112, United States
| | - Oksana Lockridge
- Department of Environmental, Agricultural & Occupational Health and Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, United States
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Estévez J, Mangas I, Sogorb MÁ, Vilanova E. Interactions of neuropathy inducers and potentiators/promoters with soluble esterases. Chem Biol Interact 2012. [PMID: 23200747 DOI: 10.1016/j.cbi.2012.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Organophosphorus compounds (OPs) cause neurotoxic disorders through interactions with well-known target esterases, such as acetylcholinesterase and neuropathy target esterase (NTE). However, the OPs can potentially interact with other esterases of unknown significance. Therefore, identifying, characterizing and elucidating the nature and functional significance of the OP-sensitive pool of esterases in the central and peripheral nervous systems need to be investigated. Kinetic models have been developed and applied by considering multi-enzymatic systems, inhibition, spontaneous reactivation, the chemical hydrolysis of the inhibitor and "ongoing inhibition" (inhibition during the substrate reaction time). These models have been applied to discriminate enzymatic components among the esterases in nerve tissues of adult chicken, this being the experimental model for delayed neuropathy and to identify different modes of interactions between OPs and soluble brain esterases. The covalent interaction with the substrate catalytic site has been demonstrated by time-progressive inhibition during ongoing inhibition. The interaction of sequential exposure to an esterase inhibitor has been tested in brain soluble fraction where exposure to one inhibitor at a non inhibitory concentration has been seen to modify sensitivity to further exposure to others. The effect has been suggested to be caused by interaction with sites other than the inhibition site at the substrate catalytic site. This kind of interaction among esterase inhibitors should be considered to study the potentiation/promotion phenomenon, which is observed when some esterase inhibitors enhance the severity of the OP induced neuropathy if they are dosed after a non neuropathic low dose of a neuropathy inducer.
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Affiliation(s)
- Jorge Estévez
- University Miguel Hernandez of Elche, Institute of Bioengineering, Unit of Toxicology and Chemical Safety, Alicante, Spain
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Mangas I, Vilanova E, Estévez J. Phenylmethylsulfonyl Fluoride, a Potentiator of Neuropathy, Alters the Interaction of Organophosphorus Compounds with Soluble Brain Esterases. Chem Res Toxicol 2012; 25:2393-401. [DOI: 10.1021/tx300257p] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Iris Mangas
- Unit of Toxicology and Chemical Safety, Institute of
Bioengineering, University “Miguel Hernández” Elche, Alicante, Spain
| | - Eugenio Vilanova
- Unit of Toxicology and Chemical Safety, Institute of
Bioengineering, University “Miguel Hernández” Elche, Alicante, Spain
| | - Jorge Estévez
- Unit of Toxicology and Chemical Safety, Institute of
Bioengineering, University “Miguel Hernández” Elche, Alicante, Spain
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Mangas I, Vilanova E, Estévez J. NTE and non-NTE esterases in brain membrane: kinetic characterization with organophosphates. Toxicology 2012; 297:17-25. [PMID: 22503708 DOI: 10.1016/j.tox.2012.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 03/27/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
Abstract
Some effects of organophosphorus compounds (OPs) esters cannot be explained by action on currently recognized targets. In this work, we evaluate and characterize the interaction (inhibition, reactivation and "ongoing inhibition") of two model compounds: paraoxon (non-neuropathy-inducer) and mipafox (neuropathy-inducer), with esterases of chicken brain membranes, an animal model, tissue and fractions, where neuropathy target esterase (NTE) was first described and isolated. Four enzymatic components were discriminated. The relative sensitivity of time-progressive inhibition differed for paraoxon and mipafox. The most sensitive component for paraoxon was also the most sensitive component for mipafox (EPα: 4.4-8.3% of activity), with I(50) (30 min) of 15-43 nM with paraoxon and 29 nM with mipafox, and it spontaneously reactivated after inhibition with paraoxon. The second most sensitive component to paraoxon (EPβ: 38.3% of activity) had I(50) (30 min) of 1540 nM, and was practically resistant to mipafox. The third component (EPγ: 38.6-47.6% of activity) was paraoxon-resistant and sensitive to micromolar concentrations of mipafox; this component meets the operational criteria of being NTE (target of organophosphorus-induced delayed neuropathy). It had I(50) (30 min) of 5.3-6.6 μM with mipafox. The fourth component (EPδ: 9.8-10.7% of activity) was practically resistant to both inhibitors. Two paraoxon-resistant and mipafox-sensitive esterases were found using the sequential assay removing paraoxon, but only one was paraoxon-resistant and mipafox-sensitive according to the assay without removing paraoxon. We demonstrate that this apparent discrepancy, interpreted as reversible NTE inhibition with paraoxon, is the result of spontaneous reactivation after paraoxon inhibition of a non-NTE component. Some of these esterases' sensitivity to OPs suggests that they may play a role in toxicity in low-level exposure to organophosphate compounds or have a protective effect related with spontaneous reactivation. The kinetic characterization of these components will facilitate further studies for isolation and molecular characterization.
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Affiliation(s)
- Iris Mangas
- Unidad de Toxicología, Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Avda. Universidad s.n. ES-03202, Elche, Alicante, Spain.
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Estévez J, Barril J, Vilanova E. Kinetics of inhibition of soluble peripheral nerve esterases by PMSF: a non-stable compound that potentiates the organophosphorus-induced delayed neurotoxicity. Arch Toxicol 2012; 86:767-77. [DOI: 10.1007/s00204-012-0817-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Accepted: 02/07/2012] [Indexed: 11/28/2022]
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Carletti E, Schopfer LM, Colletier JP, Froment MT, Nachon F, Weik M, Lockridge O, Masson P. Reaction of cresyl saligenin phosphate, the organophosphorus agent implicated in aerotoxic syndrome, with human cholinesterases: mechanistic studies employing kinetics, mass spectrometry, and X-ray structure analysis. Chem Res Toxicol 2011; 24:797-808. [PMID: 21438623 PMCID: PMC3118852 DOI: 10.1021/tx100447k] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aerotoxic syndrome is assumed to be caused by exposure to tricresyl phosphate (TCP), an antiwear additive in jet engine lubricants and hydraulic fluid. CBDP (2-(ortho-cresyl)-4H-1,2,3-benzodioxaphosphoran-2-one) is the toxic metabolite of triortho-cresylphosphate, a component of TCP. Human butyrylcholinesterase (BChE; EC 3.1.1.8) and human acetylcholinesterase (AChE; EC 3.1.1.7) are irreversibly inhibited by CBDP. The bimolecular rate constants of inhibition (k(i)), determined under pseudo-first-order conditions, displayed a biphasic time course of inhibition with k(i) of 1.6 × 10(8) M(-1) min(-1) and 2.7 × 10(7) M(-1) min(-1) for E and E' forms of BChE. The inhibition constants for AChE were 1 to 2 orders of magnitude slower than those for BChE. CBDP-phosphorylated cholinesterases are nonreactivatable due to ultra fast aging. Mass spectrometry analysis showed an initial BChE adduct with an added mass of 170 Da from cresylphosphate, followed by dealkylation to a structure with an added mass of 80 Da. Mass spectrometry in (18)O-water showed that (18)O was incorporated only during the final aging step to form phospho-serine as the final aged BChE adduct. The crystal structure of CBDP-inhibited BChE confirmed that the phosphate adduct is the ultimate aging product. CBDP is the first organophosphorus agent that leads to a fully dealkylated phospho-serine BChE adduct.
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Affiliation(s)
- Eugénie Carletti
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, 41 rue Jules Horowitz, 38027 Grenoble, France
| | - Lawrence M. Schopfer
- Eppley Institute and Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, USA
| | - Jacques-Philippe Colletier
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, 41 rue Jules Horowitz, 38027 Grenoble, France
| | - Marie-Thérése Froment
- Département de Toxicologie, Institut de Recherche Biomédicale des Armées (IRBA)-Centre de Recherches du Service de Santé des Armées (CRSSA), 24 av des Marquis du Grésivaudan, 38702 La Tronche, France
| | - Florian Nachon
- Département de Toxicologie, Institut de Recherche Biomédicale des Armées (IRBA)-Centre de Recherches du Service de Santé des Armées (CRSSA), 24 av des Marquis du Grésivaudan, 38702 La Tronche, France
| | - Martin Weik
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, 41 rue Jules Horowitz, 38027 Grenoble, France
| | - Oksana Lockridge
- Eppley Institute and Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, USA
| | - Patrick Masson
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, 41 rue Jules Horowitz, 38027 Grenoble, France
- Eppley Institute and Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, USA
- Département de Toxicologie, Institut de Recherche Biomédicale des Armées (IRBA)-Centre de Recherches du Service de Santé des Armées (CRSSA), 24 av des Marquis du Grésivaudan, 38702 La Tronche, France
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Mangas I, Vilanova E, Estévez J. Kinetics of the inhibitory interaction of organophosphorus neuropathy inducers and non-inducers in soluble esterases in the avian nervous system. Toxicol Appl Pharmacol 2011; 256:360-8. [PMID: 21600909 DOI: 10.1016/j.taap.2011.05.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 05/03/2011] [Accepted: 05/04/2011] [Indexed: 10/18/2022]
Abstract
Some published studies suggest that low level exposure to organophosphorus esters (OPs) may cause neurological and neurobehavioral effects at long term exposure. These effects cannot be explained by action on known targets. In this work, the interactions (inhibition, spontaneous reactivation and "ongoing inhibition") of two model OPs (paraoxon, non neuropathy-inducer, and mipafox, neuropathy-inducer) with the chicken brain soluble esterases were evaluated. The best-fitting kinetic model with both inhibitors was compatible with three enzymatic components. The amplitudes (proportions) of the components detected with mipafox were similar to those obtained with paraoxon. These observations confirm the consistency of the results and the model applied and may be considered an external validation. The most sensitive component (Eα) for paraoxon (11-23% of activity, I(50) (30 min)=9-11 nM) is also the most sensitive for mipafox (I(50) (30 min)=4 nM). This component is spontaneously reactivated after inhibition with paraoxon. The second sensitive component to paraoxon (Eβ, 71-84% of activity; I(50) (30 min)=1216 nM) is practically resistant to mipafox. The third component (Eγ, 5-8% of activity) is paraoxon resistant and has I(50) (30 min) of 3.4 μM with mipafox, similar to NTE (neuropathy target esterase). The role of these esterases remains unknown. Their high sensitivity suggests that they may either play a role in toxicity in low-level long-term exposure of organophosphate compounds or have a protective effect related with the spontaneous reactivation. They will have to be considered in further metabolic and toxicological studies.
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Affiliation(s)
- Iris Mangas
- Unidad de Toxicología, Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Avda. Universidad s.n. ES-03202, Elche (Alicante), Spain
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Bazire A, Gillon E, Lockridge O, Vallet V, Nachon F. The kinetic study of the inhibition of human cholinesterases by demeton-S-methyl shows that cholinesterase-based titration methods are not suitable for this organophosphate. Toxicol In Vitro 2011; 25:754-9. [DOI: 10.1016/j.tiv.2011.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 12/20/2010] [Accepted: 01/09/2011] [Indexed: 11/26/2022]
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Estévez J, García-Pérez A, Barril J, Vilanova E. Inhibition with Spontaneous Reactivation of Carboxyl Esterases by Organophosphorus Compounds: Paraoxon as a Model. Chem Res Toxicol 2010; 24:135-43. [DOI: 10.1021/tx100346c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jorge Estévez
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, Elche (Alicante), Spain
| | - Adolfo García-Pérez
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, Elche (Alicante), Spain
| | - José Barril
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, Elche (Alicante), Spain
| | - Eugenio Vilanova
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, Elche (Alicante), Spain
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Makhaeva G, Aksinenko A, Sokolov V, Baskin I, Palyulin V, Zefirov N, Hein N, Kampf J, Wijeyesakere S, Richardson R. Kinetics and mechanism of inhibition of serine esterases by fluorinated aminophosphonates. Chem Biol Interact 2010; 187:177-84. [PMID: 20035729 PMCID: PMC4820331 DOI: 10.1016/j.cbi.2009.12.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 12/13/2009] [Accepted: 12/14/2009] [Indexed: 11/25/2022]
Abstract
This paper reviews previously published data and presents new results to address the hypothesis that fluorinated aminophosphonates (FAPs), (RO)(2)P(O)C(CF(3))(2)NHS(O)(2)C(6)H(5), R=alkyl, inhibit serine esterases by scission of the P-C bond. Kinetics studies demonstrated that FAPs are progressive irreversible inhibitors of acetylcholinesterase (AChE, EC 3.1.1.7.), butyrylcholinesterase (BChE, EC 3.1.1.8.), carboxylesterase (CaE, EC 3.1.1.1.), and neuropathy target esterase (NTE, EC 3.1.1.5.), consistent with P-C bond breakage. Chemical reactivity experiments showed that diMe-FAP and diEt-FAP react with water to yield the corresponding dialkylphosphates and (CF(3))(2)CHNHS(O)(2)C(6)H(5), indicating lability of the P-C bond. X-ray crystallography of diEt-FAP revealed an elongated (and therefore weaker) P-C bond (1.8797 (13)A) compared to P-C bonds in dialkylphosphonates lacking alpha-CF(3) groups (1.805-1.822A). Semi-empirical and non-empirical molecular modeling of diEt-FAP and (EtO)(2)P(O)C(CH(3))(2)NHS(O)(2)C(6)H(5) (diEt-AP), which lacks CF(3) groups, indicated lengthening and destabilization of the P-C bond in diEt-FAP compared to diEt-AP. Active site peptide adducts formed by reacting diEt-FAP with BChE and diBu-FAP with NTE catalytic domain (NEST) were identified using peptide mass mapping with mass spectrometry (MS). Mass shifts (mean+/-SE, average mass) for peaks corresponding to active site peptides with diethylphosphoryl and monoethylphosphoryl adducts on BChE were 136.1+/-0.1 and 108.0+/-0.1Da, respectively. Corresponding mass shifts for dibutylphosphoryl and monobutylphosphoryl adducts on NEST were 191.8+/-0.2 and 135.5+/-0.1Da, respectively. Each of these values was statistically identical to the theoretical mass shift for each dialkylphosphoryl and monoalkylphosphoryl species. The MS results demonstrate that inhibition of BChE and NEST by FAPs yields dialkylphosphoryl and monoalkylphosphoryl adducts, consistent with phosphorylation via P-C bond cleavage and aging by net dealkylation. Taken together, predictions from enzyme kinetics, chemical reactivity, X-ray crystallography, and molecular modeling were confirmed by MS and support the hypothesis that FAPs inhibit serine esterases via scission of the P-C bond.
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Affiliation(s)
- G.F. Makhaeva
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432 Russia
| | - A.Y. Aksinenko
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432 Russia
| | - V.B. Sokolov
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432 Russia
| | - I.I. Baskin
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow, 119991 Russia
| | - V.A. Palyulin
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow, 119991 Russia
| | - N.S. Zefirov
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow, 119991 Russia
| | - N.D. Hein
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - J.W. Kampf
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - S.J. Wijeyesakere
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - R.J. Richardson
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
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Estévez J, Barril J, Vilanova E. Inhibition with spontaneous reactivation and the “ongoing inhibition” effect of esterases by biotinylated organophosphorus compounds: S9B as a model. Chem Biol Interact 2010; 187:397-402. [DOI: 10.1016/j.cbi.2010.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 05/11/2010] [Accepted: 05/12/2010] [Indexed: 11/15/2022]
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Pamies D, Reig JA, Vilanova E, Sogorb MA. Expression of Neuropathy Target Esterase in mouse embryonic stem cells during differentiation. Arch Toxicol 2010; 84:481-91. [DOI: 10.1007/s00204-010-0518-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Accepted: 01/14/2010] [Indexed: 11/29/2022]
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Sogorb MA, González-González I, Pamies D, Vilanova E. An alternative in vitro method for detecting neuropathic compounds based on acetylcholinesterase inhibition and on inhibition and aging of neuropathy target esterase (NTE). Toxicol In Vitro 2010; 24:942-52. [PMID: 20097283 DOI: 10.1016/j.tiv.2010.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 01/15/2010] [Accepted: 01/18/2010] [Indexed: 11/18/2022]
Abstract
Organophosphorus-induced delayed polyneuropathy (OPIDP) is a syndrome induced by certain organophosphorus compounds (OPs) through a mechanism based on the inhibition and further modification (aging) of neuropathy target esterase (NTE). OECD guidelines for testing the capability of OPs to trigger OPIDP include two in vivo tests with hens. Activities of acetylcholinesterase and NTE found in SH-SY5Y human neuroblastoma cells were inhibited by 10 different OPs with kinetics similar to those found with chicken brain enzymes (model system for in vivo and in vitro-ex vivo assays). NTE in SH-SY5Y cells inhibited by these OPs aged and reactivated similarly to that described for hen brain NTE ex vivo. In short, we have developed an alternative methodology for predicting the capability of OPs to induce OPIDP based on the inhibition kinetics of acetylcholinesterase and NTE and on the capability of OPs to age the inhibited NTE from SH-SY5Y cell line. The results obtained always agreed with the previously reported ex vivo results with hen brain. The developed methodology correctly predicted the neuropathic potential of the tested OPs in eight cases. The in vivo-in vitro discrepancies with two of the tested compounds can be explained on the basis of differences between in vivo and in vitro biotransformation.
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Affiliation(s)
- Miguel A Sogorb
- Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, 03202 Elche, Spain.
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