Detection of Dichlorvos Adducts in a Hepatocyte Cell Line
ARMY CENTER FOR ENVIRONMENTAL HEALTH RESEARCH FORT DETRICK MD
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The toxicity of dichlorvos DDVP, an organophosphate OP pesticide, classically results from modification of the serine in the active sites of cholinesterases. However, DDVP also forms adducts on unrelated targets such as transferrin and albumin, suggesting that DDVP could cause perturbations in cellular processes by modifying noncholinesterase targets. Here we identify novel DDVP-modified targets in lysed human hepatocytelike cells HepaRG using a direct liquid chromatography mass spectrometry LC MS assay of cell lysates incubated with DDVP or using a competitive pull-down experiments with a biotin-linked organophosphorus compound 10-fluoroethoxyphosphinyl-N-biotinamidopentyldecanamide FP-biotin, which competes with DDVP for similar binding sites. We show that DDVP forms adducts to several proteins important for the cellular metabolic pathways and differentiation, including glyceraldehyde-3-phosphate dehydrogenase GAPDH and actin. We validated the results using purified proteins and enzymatic assays. The study not only identified novel DDVP-modified targets but also suggested that the modification directly inhibits the enzymes. The current approach provides information for future hypothesis-based studies to understand the underlying mechanism of toxicity of DDVP in non-neuronal tissues. The MS data have been deposited to the ProteomeXchange with identifier PXD001107.