Activation of nuclear receptor CAR by an environmental pollutant perfluorooctanoic acid.
Perfluorocarboxylic acids (PFCAs) including perfluorooctanoic acid (PFOA) are environmental pollutants showing high accumulation, thermochemical stability and hepatocarcinogenicity. Peroxisome proliferator-activated receptor α is suggested to mediate their toxicities, but the precise mechanism remains unclear. Previous reports also imply a possible role of constitutive androstane receptor (CAR), a key transcription factor for the xenobiotic-induced expression of various genes involved in drug metabolism and disposition as well as hepatocarcinogenesis. Therefore, we have investigated whether PFCAs activate CAR. In wild-type but not Car-null mice, mRNA levels of Cyp2b10, a CAR target gene, were increased by PFOA treatment. PFCA treatment induced the nuclear translocation of CAR in mouse livers. Since CAR activators are divided into two types, ligand-type activators and phenobarbital-like indirect activators, we investigated whether PFCAs are CAR ligands or not using the cell-based reporter gene assay that can detect CAR ligands but not indirect activators. As results, neither PFCAs nor phenobarbital increased reporter activities. Interestingly, in mouse hepatocytes, pretreatment with the protein phosphatase inhibitor okadaic acid prevented an increase in Cyp2b10 mRNA levels induced by phenobarbital as reported, but not that by PFOA. Finally, in human hepatocyte-like HepaRG cells, PFOA treatment increased mRNA levels of CYP2B6, a CAR target gene, as did phenobarbital. Taken together, our present results suggest that PFCAs including PFOA are indirect activators of mouse and human CAR and that the mechanism might be different from that for phenobarbital. The results imply a role of CAR in the hepatotoxicity of PFCAs.
Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan.|Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.|Laboratory of Health Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan.
Taiki
T
Abe
Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
Mirei
M
Takahashi
Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
Makoto
M
Kano
Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
Yuto
Y
Amaike
Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan.
Chizuru
C
Ishii
Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan.
Kazuhiro
K
Maeda
Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan.
Yuki
Y
Kudoh
Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan.
Toru
T
Morishita
Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
Takuomi
T
Hosaka
Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
Takamitsu
T
Sasaki
Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan.
Susumu
S
Kodama
Laboratory of Health Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan.
Atsushi
A
Matsuzawa
Food Safety Group, Hokkaido Institute of Public Health, Kita-19, Nishi-12, Kita-ku, Sapporo, 060-0819, Japan.
Hiroyuki
H
Kojima
Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan. yoshinari@u-shizuoka-ken.ac.jp.|Department of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan. yoshinari@u-shizuoka-ken.ac.jp.
Kouichi
http://orcid.org/0000-0002-2027-2017
K
Yoshinari
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D002210:Caprylates / Q000633:toxicity*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D000090702:Constitutive Androstane Receptor; D000072467:Cytochrome P450 Family 2 / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004785:Environmental Pollutants / Q000633:toxicity*; D005466:Fluorocarbons / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D047493:PPAR alpha / Q000235:genetics / Q000378:metabolism; D061251:Primary Cell Culture; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D013250:Steroid Hydroxylases / Q000378:metabolism*
D002210:Caprylates; D000090702:Constitutive Androstane Receptor; D004785:Environmental Pollutants; D005466:Fluorocarbons; D047493:PPAR alpha; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; C023036:perfluorooctanoic acid; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C101679:Cyp2b10 protein, mouse; D000072467:Cytochrome P450 Family 2
Cytochrome P450; Environmental pollutant; Hepatocarcinogenesis; Liver hypertrophy; Nuclear receptor