title: B-esterase determination and organophosphate insecticide inhibitory effects in JEG-3 trophoblasts.
abstract: The placenta and trophoblasts express several B-esterases. This family includes acethylcholinesterase (AChE), carboxylesterase (CES) and butyrylcholinesterase (BChE), which are important targets of organophosphate insecticide (OP) toxicity. To better understand OP effects on trophoblasts, B-esterase basal activity and kinetic behavior were studied in JEG-3 choriocarcinoma cell cultures. Effects of the OP azinphos-methyl (Am) and chlorpyrifos (Cp) on cellular enzyme activity were also evaluated. JEG-3 cells showed measurable activity levels of AChE and CES, while BChE was undetected. Recorded Km for AChE and CES were 0.33 and 0.26 mM respectively. Native gel electrophoresis and RT-PCR analysis demonstrated CES1 and CES2 isoform expression. Cells exposed for 4 and 24 h to the OP Am or Cp, showed a differential CES and AChE inhibition profiles. Am inhibited CES and AChE at 4 h treatment while Cp showed the highest inhibition profile at 24 h. Interestingly, both insecticides differentially affected CES1 and CES2 activities. Results demonstrated that JEG-3 trophoblasts express AChE, CES1 and CES2. B-esterase enzymes were inhibited by in vitro OP exposure, indicating that JEG-3 cells metabolization capabilities include phase I enzymes, able to bioactivate OP. In addition, since CES enzymes are important for medicinal drug activation/deactivation, OP exposure may interfere with trophoblast CES metabolization, probably being relevant in a co-exposure scenario during pregnancy.
authors.affiliation: Departamento de Ciencias del Ambiente, Facultad de Ciencias del Ambiente y la Salud, Universidad Nacional del Comahue, Neuquén, Argentina.
authors.forename: Marlon
authors.initials: M
authors.lastname: Espinoza
authors.affiliation: Facultad de Medicina, Universidad Nacional del Comahue, Río Negro, Argentina.
authors.forename: Valeria
authors.initials: V
authors.lastname: Rivero Osimani
authors.affiliation: LIBIQUIMA, Facultad de Ingeniería, Universidad Nacional del Comahue, Neuquén, Argentina.
authors.forename: Victoria
authors.initials: V
authors.lastname: Sánchez
authors.affiliation: LIBIQUIMA, Facultad de Ingeniería, Universidad Nacional del Comahue, Neuquén, Argentina.
authors.forename: Enrique
authors.initials: E
authors.lastname: Rosenbaum
authors.affiliation: Departamento de Ciencias del Ambiente, Facultad de Ciencias del Ambiente y la Salud, Universidad Nacional del Comahue, Neuquén, Argentina; LIBIQUIMA, Facultad de Ingeniería, Universidad Nacional del Comahue, Neuquén, Argentina. Electronic address: natanien@hotmail.com.
authors.forename: Natalia
authors.initials: N
authors.lastname: Guiñazú
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D001387:Azinphosmethyl / Q000633:toxicity*; D002091:Butyrylcholinesterase / Q000378:metabolism; D043182:Carboxylesterase / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D004390:Chlorpyrifos / Q000633:toxicity*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D006801:Humans; D007306:Insecticides / Q000633:toxicity*; D012333:RNA, Messenger / Q000378:metabolism; D014327:Trophoblasts / Q000187:drug effects* / Q000201:enzymology
chemical_list: D002800:Cholinesterase Inhibitors; D007306:Insecticides; D012333:RNA, Messenger; D001387:Azinphosmethyl; D043182:Carboxylesterase; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase; D004390:Chlorpyrifos
keywords: Acetylcholinesterase; Azinphos-methyl; Carboxylesterase; Chlorpyrifos; Organophosphate pesticides