Characterization of drug transport mechanism across the placental barrier using cultured trophoblast

摘要

Drug transport mechanism across the placenta is still unknown.The trophoblast that from the placental barrier have an important role in controlling the passage of molecules from mother to fetus.In this study,we investigated that dipeptide and folic acid are actively transported by transporters on the trophoblast.The human choriocarcinoma cell line.BeWo,was cultured on tissue culture plates.When the cells reached confluence,durg uptake experiments were performed.The uptake of [~(14)C]glycylsarcosine ([~(14)C]Gly-Sar)by BeWo cells was saturated at higher concentration.The metabolic inhibitors singnificantly inhibited the uptake of [~(14)C]Gly-Sar.In addition,various di- or tri- peptides inhibited the uptake of [~(14)C]Gly-Sar.The uptake of [~3H]folic acid was saturable at higher concentrations and inhibited by metabolic ilhibitors.Analogs of folic acid,methotrexate and 5-methyltetrahydrofolate,inhibited the uptake of [~3H]folic acid by BeWo cells.Kinetic analysis using Lineweaver-Burk plots revealed that methotrezate competitively inhibited the uptake of [~3H]folic acid and folic acid competitively inhibited the uptake of [~3H]methotrexate.The findings confirm that dipeptide and folic acid are transported by their transporters on BeWo cell monolayers.The dehydroepiandrosteron sulfate (DHEAS)uptake by BeWo cells from basal side of the cells was higher than that from apical side,and the uptake was inhibited by am excess amount of DHEAS.The findings confirm that the carrier of DHEAS exists on the basal membrane of BeWo cells.This work demonstrated the possibility of using a human monolayer-forming cell line.BeWo,to characterize putative trans-trophoblast transport mechanisms and their potential roles in controlling nutrients and drug across the placental barrier.