Generation of Mice Transgenic for Human<i>CYP2C18</i>and<i>CYP2C19</i>: Characterization of the Sexually Dimorphic Gene and Enzyme Expression

Löfgren, Susanne; Baldwin, Margaret; Hiratsuka, Masahiro; LINDQVIST, A; Carlberg, Anne; Sim, Sarah C.; Schülke, Meint; Snait, Michael; Edenro, Anne; Fransson-Steen, Ronny; Terelius, Ylva; Ingelman‐Sundberg, Magnus

doi:10.1124/dmd.107.019349

Cited by 45 publications

(41 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Thus, the human CYP3A4 gene contains all of the DNA sequence elements required to respond to the endogenous mouse hormonal environment, leading to a pattern of postnatal developmental regulation, adult sexual dimorphism, and plasma GH-responsiveness very similar to that of the endogenous female-specific, GH-regulated mouse Cyp3a genes. Sex-specificity and GH regulation have also been observed for CYP2C18 and CYP2C19 in a transgenic mouse liver model, where introduction of these tandem human genes together with flanking regulatory sequences results in hepatic expression that is male-specific and suppressed by continuous GH treatment (Löfgren et al, 2008). Further investigation will be required to ascertain the relevance of these findings in transgenic mice to the expression of these P450 genes in humans, which differ from mice in terms of their plasma GH profiles and other physiological factors.…”

Section: Gonadal and Pituitary Hormonal Determinants Of Hepatic Sex Dmentioning

confidence: 94%

Sex Differences in the Expression of Hepatic Drug Metabolizing Enzymes

Waxman

Holloway²

2009

Molecular Pharmacology

634

584

View full text Add to dashboard Cite

Sex differences in pharmacokinetics and pharmacodynamics characterize many drugs and contribute to individual differences in drug efficacy and toxicity. Sex-based differences in drug metabolism are the primary cause of sex-dependent pharmacokinetics and reflect underlying sex differences in the expression of hepatic enzymes active in the metabolism of drugs, steroids, fatty acids and environmental chemicals, including cytochromes P450 (P450s), sulfotransferases, glutathione transferases, and UDP-glucuronosyltransferases. Studies in the rat and mouse liver models have identified more than 1000 genes whose expression is sex-dependent; together, these genes impart substantial sexual dimorphism to liver metabolic function and pathophysiology. Sex differences in drug metabolism and pharmacokinetics also occur in humans and are due in part to the female-predominant expression of CYP3A4, the most important P450 catalyst of drug metabolism in human liver. The sexually dimorphic expression of P450s and other liver-expressed genes is regulated by the temporal pattern of plasma growth hormone (GH) release by the pituitary gland, which shows significant sex differences. These differences are most pronounced in rats and mice, where plasma GH profiles are highly pulsatile (intermittent) in male animals versus more frequent (nearly continuous) in female animals. This review discusses key features of the cell signaling and molecular regulatory mechanisms by which these sex-dependent plasma GH patterns impart sex specificity to the liver. Moreover, the essential role proposed for the GH-activated transcription factor signal transducer and activator of transcription (STAT) 5b, and for hepatic nuclear factor (HNF) 4␣, as mediators of the sexdependent effects of GH on the liver, is evaluated. Together, these studies of the cellular, molecular, and gene regulatory mechanisms that underlie sex-based differences in liver gene expression have provided novel insights into the physiological regulation of both xenobiotic and endobiotic metabolism.

show abstract

Section: Gonadal and Pituitary Hormonal Determinants Of Hepatic Sex Dmentioning

confidence: 94%

Sex Differences in the Expression of Hepatic Drug Metabolizing Enzymes

Waxman

Holloway²

2009

Molecular Pharmacology

634

584

View full text Add to dashboard Cite

show abstract

“…Alternatively, the P450 proteins, or at least peptide antigens derived therefrom, may be more resistant to degradation during the postmortem delay compared with mRNA. Significantly, both CYP2C18 and CYP2C19 were expressed in the brain at the mRNA level in mice transgenic for these two genes (Löfgren et al, 2008). Moreover, in the liver, P450 protein expression correlates with mRNA transcript levels for only some P450s (Ohtsuki et al, 2012).…”

Section: Downloaded Frommentioning

confidence: 95%

Differential Expression of Cytochrome P450 Enzymes from the CYP2C Subfamily in the Human Brain

et al. 2014

View full text Add to dashboard Cite

Cytochrome P450 enzymes from the CYP2C subfamily play a prominent role in the metabolic clearance of many drugs. CYP2C enzymes have also been implicated in the metabolism of arachidonic acid to vasoactive epoxyeicosatrienoic acids. CYP2C8, CYP2C9, and CYP2C19 are expressed in the adult liver at significant levels; however, the expression of CYP2C enzymes in extrahepatic tissues such as the brain is less well characterized. Form-specific antibodies to CYP2C9 and CYP2C19 were prepared by affinity purification of antibodies raised to unique peptides. CYP2C9 and CYP2C19 were located in microsomal fractions of all five human brain regions examined, namely the frontal cortex, hippocampus, basal ganglia, amygdala, and cerebellum. Both CYP2C9 and CYP2C19 were detected predominantly within the neuronal soma but with expression extending down axons and dendrites in certain regions. Finally, a comparison of cortex samples from alcoholics and age-matched controls suggested that CYP2C9 expression was increased in alcoholics. IntroductionCytochrome P450 (P450) enzymes play a dominant role in the metabolic clearance of drugs and other environmental chemicals. However, it is increasingly apparent that P450s are expressed differentially in extrahepatic tissues in a region-specific fashion that may influence the tissue-specific clearance of drugs. In particular, P450s are expressed in the brain in a highly cell-specific fashion. Localized metabolism of drugs in the brain may have significant implications for the efficacy and side-effect profile of neuroactive medicines. Given the role of CYP2C forms in the metabolism of a number of drugs affecting the central nervous system (Guengerich, 2005), it is of significant interest to characterize their expression in the brain. Moreover, CYP2C enzymes in animals have been proposed to contribute to the regulation of cerebral blood flow via generation of epoxyeicosatrienoic acid metabolites from arachidonic acid (Alkayed et al., 1996;Iliff et al., 2007). Although a few studies have been undertaken to detect CYP2C transcript expression in the human brain (McFayden et al., 1998;Klose et al., 1999;Dauchy et al., 2008;Dutheil et al., 2009), the detection of CYP2C proteins has been limited by the paucity of human brain tissue and form-specific antibodies. This study aimed to characterize the expression of CYP2C9 and CYP2C19 proteins in discrete regions of the human brain. Materials and MethodsPolyvinylidene fluoride and BioTrace NT nitrocellulose membranes were obtained from Pall Corporation (East Hills, NY). Alexa Fluor 680-and Alexa Fluor 488-labeled goat anti-rabbit IgG antibodies were purchased from Invitrogen (Carlsbad, CA) and IRDye 800-labeled donkey anti-mouse IgG antibody was obtained from Rockland Immunochemicals (Gilbertsville, PA). Mouse antihuman-a-tubulin monoclonal primary antibody was purchased from Sigma (St. Louis, MO). Fluorescence mounting medium (DAKO, Glostrup, Denmark) was used to maintain fluorophore stability.All work described here was done under protocols appro...

show abstract

“…CYP2C18/CYP2C19 hemizygous transgenic mice (Löfgren et al, 2008) and wild-type C57BL/6OlaHsd littermates were housed at the Karolinska Institute in Stockholm and were treated according to research protocols approved by the Swedish Ethical Application Committee. The mice were housed on wood shavings in plastic cages, with water and commercial mouse diet supplied ad libitum.…”

Section: Methodsmentioning

confidence: 99%

“…Microsomes from 3-and 9-week-old, wild-type and transgenic mice were prepared from individual male and female mouse livers as described previously (Löfgren et al, 2008) but were ultimately pooled by volume because of the limited amount of microsomal proteins obtained. Metabolism of S-mephenytoin to its major CYP2C19-dependent metabolite 4Ј-hydroxymephenytoin was measured as described previously (Löfgren et al, 2008) with the exception that a final S-mephenytoin solvent concentration of 1% methanol was used in each microsomal incubation. Michaelis-Menten kinetics was assumed, and apparent K m and V max values were estimated for all the groups using Lineweaver-Burke plots.…”

Section: Methodsmentioning

confidence: 99%

“…These environmental factors can be controlled in animals maintained under defined dietary and environmental conditions, suggesting that animal models, including transgenic mice, may be useful for investigation of the gender-specific expression and hormonal regulation of human P450 enzymes. Thus, recently we found strong gender differences in human P450 gene and enzyme expression in a humanized CYP2C18/ CYP2C19 transgenic mouse line, where adult male mice expressed much higher CYP2C18 and CYP2C19 mRNA levels in liver and kidney compared with that in female mice (Löfgren et al, 2008).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Regulation of Human CYP2C18 and CYP2C19 in Transgenic Mice: Influence of Castration, Testosterone, and Growth Hormone

et al. 2009

Self Cite

View full text Add to dashboard Cite

ABSTRACT:The hormonal regulation of human CYP2C18 and CYP2C19, which are expressed in a male-specific manner in liver and kidney in a mouse transgenic model, was examined. The influence of prepubertal castration in male mice and testosterone treatment of female mice was investigated, as was the effect of continuous administration of growth hormone (GH) to transgenic males. Prepubertal castration of transgenic male mice suppressed the expression of CYP2C18 and CYP2C19 in liver and kidney to female levels, whereas expression was increased for the endogenous female-specific mouse hepatic genes Cyp2c37, Cyp2c38, Cyp2c39, and Cyp2c40. Testosterone treatment of female mice increased CYP2C18 and CYP2C19 expression in kidney, and to a lesser extent in liver, but was without effect in brain or small intestine, where gene expression was not gender-dependent. Continuous GH treatment of transgenic males for 7 days suppressed hepatic expression of CYP2C19 (>90% decrease) and CYP2C18 (ϳ50% decrease) but had minimal effect on the expression of these genes in kidney, brain, or small intestine. Under these conditions, continuous GH induced all four female-specific mouse liver Cyp2c genes in males to normal female levels. These studies indicate that the human CYP2C18 and CYP2C19 genes contain regulatory elements that respond to the endogenous mouse hormonal profiles, with androgen being the primary regulator of male-specific expression in kidney, whereas the androgen-dependent pituitary GH secretory pattern is the primary regulator of male-specific expression in liver in a manner that is similar to the regulation of the endogenous gender-specific hepatic genes.

show abstract

Generation of Mice Transgenic for HumanCYP2C18andCYP2C19: Characterization of the Sexually Dimorphic Gene and Enzyme Expression

Cited by 45 publications

References 35 publications

Sex Differences in the Expression of Hepatic Drug Metabolizing Enzymes

Sex Differences in the Expression of Hepatic Drug Metabolizing Enzymes

Differential Expression of Cytochrome P450 Enzymes from the CYP2C Subfamily in the Human Brain

Regulation of Human CYP2C18 and CYP2C19 in Transgenic Mice: Influence of Castration, Testosterone, and Growth Hormone

Contact Info

Product

Resources

About