title: Application of human placental villous tissue explants to study ABC transporter mediated efflux of 2,4-dinitrophenyl-S-glutathione.
abstract: OBJECTIVE
  The purpose of this study was to characterize the human term placental villous tissue explant culture model as a tool to study the formation and efflux of 1-chloro-2,4-dinitrobenzene (CDNB) conjugate 2,4-dinitrophenyl-S-glutathione (DNP-SG) as a model system for phase II metabolism and ATP-binding cassette (ABC) transporter-mediated cellular efflux.
  
  
  METHODS
  Placental tissue samples were obtained after cesarean section following normal pregnancies (n=9). Cultured villous tissue was monitored up to 48 h to study the effect of time in culture on biochemical parameters, formation and efflux of DNP-SG in the absence or presence of ATPase inhibitor sodium orthovanadate and the protein expression of ABC transporters - multidrug resistance associated protein 2 (MRP2), P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and enzyme glutathione-S-transferase isoform P1-1 (GSTP1-1).
  
  
  RESULTS
  Villous tissue structure, tissue viability and expression of BCRP, GSTP1-1 remained unchanged, while expression of MRP2, P-gp and total tissue glutathione decreased with time in culture. Tissue integrity was unchanged up to 24 h but declined at 48 h. However, DNP-SG formation, DNP-SG efflux, and the extent of inhibition of DNP-SG efflux by sodium orthovanadate showed only minor changes through 48 h. Sodium orthovanadate decreased DNP-SG efflux, consistent with inhibition of apical ABC transporters.
  
  
  CONCLUSIONS
  The results support the use of the cultured human term placental villous tissue explants model to study coordinated function of GSTP1-1 and apical ABC transporters in the formation and efflux of the model substrate DNP-SG.
authors.affiliation: Department of Pharmaceutics, Virginia Commonwealth University, MCV Campus, 410 N. 12 Street, PO Box 980533, Richmond, VA 23298-0533, USA.
authors.forename: Soniya S
authors.initials: SS
authors.lastname: Vaidya
authors.forename: Scott W
authors.initials: SW
authors.lastname: Walsh
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Gerk
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D001692:Biological Transport; D002824:Chorionic Villi / Q000378:metabolism*; D004137:Dinitrochlorobenzene / Q000378:metabolism; D005260:Female; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism; D051549:Glutathione S-Transferase pi / Q000378:metabolism; D006801:Humans; D050217:Metabolic Detoxication, Phase II; D011247:Pregnancy; D046509:Tissue Culture Techniques; D014638:Vanadates / Q000494:pharmacology; D055815:Young Adult
chemical_list: D018528:ATP-Binding Cassette Transporters; D004137:Dinitrochlorobenzene; C030190:S-(2,4-dinitrophenyl)glutathione; D014638:Vanadates; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D005978:Glutathione