Nuclear pregnane x receptor and constitutive androstane receptor regulate overlapping but distinct sets of genes involved in xenobiotic detoxification.
The nuclear pregnane X receptor (PXR) and constitutive androstane receptor (CAR) play central roles in protecting the body against environmental chemicals (xenobiotics). PXR and CAR are activated by a wide range of xenobiotics and regulate cytochrome P450 and other genes whose products are involved in the detoxification of these chemicals. In this report, we have used receptor-selective agonists together with receptor-null mice to identify PXR and CAR target genes in the liver and small intestine. Our results demonstrate that PXR and CAR regulate overlapping but distinct sets of genes involved in all phases of xenobiotic metabolism, including oxidative metabolism, conjugation, and transport. Among the murine genes regulated by PXR were those encoding PXR and CAR. We provide evidence that PXR regulates a similar program of genes involved in xenobiotic metabolism in human liver. Among the genes regulated by PXR in primary human hepatocytes were the aryl hydrocarbon receptor and its target genes CYP1A1 and CYP1A2. These findings underscore the importance of these two nuclear receptors in defending the body against a broad array of potentially harmful xenobiotics.
Maglich
Jodi M
JM
Nuclear Receptor Discovery Research, GlaxoSmithKline, Research Triangle Park, North Carolina, USA.
Stoltz
Catherine M
CM
Goodwin
Bryan
B
Hawkins-Brown
Diane
D
Moore
John T
JT
Kliewer
Steven A
SA
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D002478:Cells, Cultured; D000090702:Constitutive Androstane Receptor; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D008658:Inactivation, Metabolic / Q000502:physiology; D007421:Intestine, Small / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D051379:Mice; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D000077297:Pregnane X Receptor; D018160:Receptors, Cytoplasmic and Nuclear / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D011987:Receptors, Steroid / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013250:Steroid Hydroxylases / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D015262:Xenobiotics / Q000378:metabolism*
D001189:Aryl Hydrocarbon Hydroxylases; D000090702:Constitutive Androstane Receptor; D003577:Cytochrome P-450 Enzyme System; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D000077297:Pregnane X Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D013250:Steroid Hydroxylases; D014157:Transcription Factors; D015262:Xenobiotics; C114462:multidrug resistance-associated protein 3; C050356:steroid 15-alpha-hydroxylase