Post-VX exposure treatment of rats with engineered phosphotriesterases
| Autor: | Lisa Stigler, Anja Köhler, Marianne Koller, Laura Job, Benjamin Escher, Heidrun Potschka, Horst Thiermann, Arne Skerra, Franz Worek, Timo Wille |
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| Rok vydání: | 2021 |
| Předmět: |
Male
Health Toxicology and Mutagenesis Organothiophosphorus Compounds Stereoisomerism Caulobacteraceae General Medicine Protein Engineering Molecular Toxicology Acetylcholinesterase Catalytic bioscavenger Detoxification Enzyme engineering In vivo Organophosphate PASylation Phosphotriesterase Therapy VX Toxicology Rats ddc Phosphoric Triester Hydrolases Animals Chemical Warfare Agents Cholinesterase Inhibitors Rats Wistar |
| Zdroj: | Archives of Toxicology. 96:571-583 |
| ISSN: | 1432-0738 0340-5761 |
| DOI: | 10.1007/s00204-021-03199-6 |
| Popis: | The biologically stable and highly toxic organophosphorus nerve agent (OP) VX poses a major health threat. Standard medical therapy, consisting of reactivators and competitive muscarinic receptor antagonists, is insufficient. Recently, two engineered mutants of the Brevundimonas diminuta phosphotriesterase (PTE) with enhanced catalytic efficiency (kcat/KM = 21 to 38 × 106 M−1 min−1) towards VX and a preferential hydrolysis of the more toxic P(−) enantiomer were described: PTE-C23(R152E)-PAS(100)-10-2-C3(I106A/C59V/C227V/E71K)-PAS(200) (PTE-2), a single-chain bispecific enzyme with a PAS linker and tag having enlarged substrate spectrum, and 10-2-C3(C59V/C227V)-PAS(200) (PTE-3), a stabilized homodimeric enzyme with a double PASylation tag (PAS-tag) to reduce plasma clearance. To assess in vivo efficacy, these engineered enzymes were tested in an anesthetized rat model post-VX exposure (~ 2LD50) in comparison with the recombinant wild-type PTE (PTE-1), dosed at 1.0 mg kg−1 i.v.: PTE-2 dosed at 1.3 mg kg−1 i.v. (PTE-2.1) and 2.6 mg kg−1 i.v. (PTE-2.2) and PTE-3 at 1.4 mg kg−1 i.v. Injection of the mutants PTE-2.2 and PTE-3, 5 min after s.c. VX exposure, ensured survival and prevented severe signs of a cholinergic crisis. Inhibition of erythrocyte acetylcholinesterase (AChE) could not be prevented. However, medulla oblongata and diaphragm AChE activity was partially preserved. All animals treated with the wild-type enzyme, PTE-1, showed severe cholinergic signs and died during the observation period of 180 min. PTE-2.1 resulted in the survival of all animals, yet accompanied by severe signs of OP poisoning. This study demonstrates for the first time efficient detoxification in vivo achieved with low doses of heterodimeric PTE-2 as well as PTE-3 and indicates the suitability of these engineered enzymes for the development of highly effective catalytic scavengers directed against VX. |
| Databáze: | OpenAIRE |
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