STUDY OF PHASE I AND II ENZYMES IN HTR-8/SVNEO AND BEWO TROPHOBLASTS AFTER EXPOSURE TO PESTICIDES

BURGOS CAROLINA; RODRIGUEZ PIUQUE; VERA BERTA; ONDARZA PAOLA; GUIÑAZÚ NATALIA

Mar del Plata

Congreso; Reunión anual de sociedades de biociencias; 2023

Sociedad Argentina de Investigación Clínica

Chemical contaminants can be detoxified by cellular mechanisms, mainly by phase I and phase II enzyme metabolism. Carboxylesterases (CES) are phase I enzymes that detoxify carboxylic esters and 3 isoforms exists, CES1, CES2 and CES3. Glutathione S-transferases (GST) are phase II enzymes that ligates reduced glutathione (GSH) to the toxic compound, to increase solubility and facilitate its excretion. Several isoforms of GST have been reported. Both CES and GST have demonstrated beneficial impacts during pesticide intoxication. The objective of this work was to evaluate phase I and II enzymes in HTR-8/SVneo and BeWo, first and third trimester trophoblasts, after exposure to the organophosphate pesticide chlorpyrifos (CP).HTR-8/SVneo and BeWo cells were incubated for 24 h at different concentrations (0.1-100 uM) of CP 99.9% pure. DMSO 0.04% was the control condition (C). Basal expression of the CES1, CES2, CES3 and GST-P and GST-M isoforms were evaluated by conventional RT-PCR. CES activity was determined by fluorometric technique with 4-MUBA substrate. The GST activity was determined by Habig’s method. GSH content was determined by Ellman’s method. Preliminary results indicate that BeWo cells mainly expressed CES1 while HTR-8/SVneo mainly CES2 isoform. Both GST-P and GST-M were expressed by BeWo and HTR-8/SVneo cells. CES and GST activities showed non-significant changes, in both cell lines. GSH content was significantly increased in CP 100 µM (44.3±14.2) vs C (17.15±8.9) (mean±SD) ƞmol/mg prot (p=0.0481, Dunnett) only in HTR-8/SVneo cells. These results suggest that CES isoforms are differentially expressed in first-and third trimester cells. CES 1 and 2 have shown different sensibility to OP inhibition, however incubation with CP did not alter the activity of CES. Similarly, CP did not modify GST activity in both cell lines. The significant increase in GSH suggests the possible induction of other enzymes important for the GSH levels, such as glutathione reductase.