RRC ID 38472
著者 Inoue S, Yoshinari K, Sugawara M, Yamazoe Y.
タイトル Activated sterol regulatory element-binding protein-2 suppresses hepatocyte nuclear factor-4-mediated Cyp3a11 expression in mouse liver.
ジャーナル Mol Pharmacol
Abstract Sterol regulatory element-binding protein-2 (SREBP-2) is a key transcription factor for the cholesterol homeostasis. Recent studies have suggested the association of CYP3A enzymes, major drug-metabolizing enzymes, with cholesterol metabolism. In the present study, we have investigated a possible involvement of SREBP-2 in hepatic Cyp3a11 expression. Feeding a low-cholesterol diet (LCD) to mice activated hepatic SREBP-2 whereas it attenuated hepatic Cyp3a11 expression. These phenomena were reversed by cholesterol supplementation to LCD. In reporter assays, the overexpression of constitutively active SREBP-2 reduced Cyp3a11 reporter activity through the region from -1581 to -1570 of Cyp3a11. This region contained a putative hepatocyte nuclear factor-4α (HNF-4α) binding motif, and HNF-4α, but not SREBP-2, bound to the motif in in vitro binding assays. With the mutation or deletion of this motif, the SREBP-2-dependent suppression of Cyp3a11 expression disappeared in reporter assays. In pull-down assays and coimmunoprecipitation assays, SREBP-2 bound to peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a major coactivator for HNF-4α, via its transactivation domain and inhibited the interaction between HNF-4α and PGC-1α in vitro. A mutant SREBP-2 lacking the transactivation domain consistently failed to reduce Cyp3a11 reporter activity. Furthermore, PGC-1α overexpression relieved the SREBP-2-mediated reduction of Cyp3a11 reporter activity. Finally, chromatin immunoprecipitation assays demonstrated that the extent of PGC-1α binding to the Cyp3a11 promoter was reduced by LCD-feeding in mouse livers. In conclusion, activated SREBP-2 interacts with PGC-1α in mouse livers at reduced cholesterol intake. This results in the reduced PGC-1α recruitment to HNF-4α on the Cyp3a11 promoter and the subsequent down-regulation of Cyp3a11 expression.
巻・号 79(1)
ページ 148-56
公開日 2011-1-1
DOI 10.1124/mol.110.068577
PII mol.110.068577
PMID 20926756
MeSH Animals Cholesterol, Dietary / administration & dosage Cytochrome P-450 CYP3A / biosynthesis Cytochrome P-450 CYP3A Inhibitors* Gene Expression Regulation, Enzymologic* Hep G2 Cells Hepatocyte Nuclear Factor 4 / antagonists & inhibitors* Hepatocyte Nuclear Factor 4 / physiology Humans Liver / drug effects Liver / metabolism* Male Membrane Proteins / antagonists & inhibitors* Membrane Proteins / biosynthesis Mice Mice, Inbred C57BL Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha Salmon Sterol Regulatory Element Binding Protein 2 / metabolism* Trans-Activators / metabolism* Transcription Factors
IF 3.664
引用数 20
WOS 分野 PHARMACOLOGY & PHARMACY
リソース情報
ヒト・動物細胞