title: Basal efflux of bile acids contributes to drug-induced bile acid-dependent hepatocyte toxicity in rat sandwich-cultured hepatocytes.
abstract: The bile salt export pump (BSEP or Bsep) functions as an apical transporter to eliminate bile acids (BAs) from hepatocytes into the bile. BSEP or Bsep inhibitors engender BA retention, suggested as an underlying mechanism of cholestatic drug-induced liver injury. We previously reported a method to evaluate BSEP-mediated BA-dependent hepatocyte toxicity by using sandwich-cultured hepatocytes (SCHs). However, basal efflux transporters, including multidrug resistance-associated proteins (MRP or Mrp) 3 and 4, also participate in BA efflux. This study examined the contribution of basal efflux transporters to BA-dependent hepatocyte toxicity in rat SCHs. The apical efflux of [(3)H]taurocholic acid (TC) was potently inhibited by 10 μM cyclosporine A (CsA), with later inhibition of basal [(3)H]TC efflux, while MK571 simultaneously inhibited both apical and basal [(3)H]TC efflux. CsA-induced BA-dependent hepatocyte toxicity was 30% at most at 10 μM CsA and ∼60% at 50 μM, while MK571 exacerbated hepatocyte toxicity at concentrations of ≥50 μM. Quinidine inhibited only basal [(3)H]TC efflux and showed BA-dependent hepatocyte toxicity in rat SCHs. Hence, inhibition of basal efflux transporters as well as Bsep may precipitate BA-dependent hepatocyte toxicity in rat SCHs.
authors.affiliation: The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Susukida
authors.affiliation: The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Sekine
authors.affiliation: The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Ogimura
authors.affiliation: The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
authors.affiliation: The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Oizumi
authors.affiliation: Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Tokyo, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Horie
authors.affiliation: The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan. Electronic address: itokousei@chiba-u.jp.
authors.forename: Kousei
authors.initials: K
authors.lastname: Ito
mesh_terms: D000074020:ATP Binding Cassette Transporter, Subfamily B, Member 11; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism*; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D002779:Cholestasis; D016572:Cyclosporine / Q000494:pharmacology; D057809:HEK293 Cells; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D011422:Propionates / Q000494:pharmacology; D011802:Quinidine / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D017207:Rats, Sprague-Dawley
chemical_list: D000074020:ATP Binding Cassette Transporter, Subfamily B, Member 11; D018528:ATP-Binding Cassette Transporters; D001647:Bile Acids and Salts; D016572:Cyclosporine; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011422:Propionates; D011802:Quinidine; D011804:Quinolines; C490548:Abcb11 protein, rat; C489542:Abcc4 protein, rat; C114462:multidrug resistance-associated protein 3; C059141:verlukast
keywords: Bile acid; Bile salt export pump; Drug-induced liver injury; Multidrug resistance-associated protein; Sandwich-cultured hepatocyte