title: Expression of human cytochromes P450 in chimeric mice with humanized liver.
abstract: Recently, a chimeric mouse line in which the liver could be replaced by more than 80% with human hepatocytes was established in Japan. Because the chimeric mouse produces human albumin (hAlb), replacement by human hepatocytes could be estimated by the hAlb concentration in the blood of chimeric mice. In this study, we investigated human major cytochrome P450 (P450) in the livers of chimeric mice by mRNA, protein, and enzyme activity using real-time polymerase chain reaction, Western blot analysis, and high-performance liquid chromatography, respectively. Chimeric mice with humanized liver generated using hepatocytes from a Japanese and white donor were used. Human P450 mRNAs were expressed in the liver of chimeric mice, and major human P450 proteins such as CYP1A2, CYP2C9, and CYP3A4 were detected. The expression of P450 mRNA and protein was correlated with the hAlb concentration in the blood. The enzyme activities such as diclofenac 4'-hydroxylase activity, dexamethasone 6-hydroxylase activity, and coumarin 7-hydroxylase activity, activities that are specific to human P450 but not to murine P450, were increased in a hAlb concentration-dependent manner. The chimeric mice with nearly 90% replacement by human hepatocytes demonstrated almost the same protein contents of human P450s and drug-metabolizing enzyme activity as those of the donor. It was confirmed that genomic DNA from the livers of the chimeric mice and that from the liver of the donor exhibited the same genotype. In conclusion, the chimeric mice exhibited a similarly efficient capacity of drug metabolism as humans, suggesting that they could be a useful animal model for drug development.
authors.affiliation: Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Katoh
authors.forename: Tomohito
authors.initials: T
authors.lastname: Matsui
authors.forename: Miki
authors.initials: M
authors.lastname: Nakajima
authors.forename: Chise
authors.initials: C
authors.lastname: Tateno
authors.forename: Miho
authors.initials: M
authors.lastname: Kataoka
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Soeno
authors.forename: Toru
authors.initials: T
authors.lastname: Horie
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Iwasaki
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Yoshizato
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yokoi
mesh_terms: D000483:Alleles; D000818:Animals; D017690:Cell Transplantation; D002648:Child; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005838:Genotype; D022781:Hepatocytes / Q000502:physiology; D006801:Humans; D015151:Immunoblotting; D007223:Infant; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D012709:Serum Albumin / Q000096:biosynthesis / Q000235:genetics
chemical_list: D007527:Isoenzymes; D012709:Serum Albumin; D012313:RNA; D003577:Cytochrome P-450 Enzyme System