title: Identification of Candidate Target Cyp Genes for microRNAs Whose Expression Is Altered by PCN and TCPOBOP, Representative Ligands of PXR and CAR.
abstract: MicroRNAs (miRNAs) are small non-coding RNAs that are involved in mRNA post-transcriptional regulation. The deregulation of miRNAs affects the expression of drug-metabolizing enzymes, drug transporters, and nuclear receptors, all of which are important in regulating drug metabolism. miRNA expression can be altered by several endogenous or exogenous agents, such as steroid hormones, carcinogens, and therapeutic drugs. However, it is unclear whether hepatic miRNA expression is regulated by nuclear receptors, such as pregnane X receptor (PXR) and constitutive androstane receptor (CAR), which are indispensable for the expression of the CYPs. Here we investigated the effects of the mouse PXR and CAR ligands pregnenolone-16α-carbonitrile (PCN) and 1,4-bis[(3,5-dichloropyridin-2-yl)oxy]benzene (TCPOBOP) on hepatic miRNA expression in mice. We found that the expression of 9 miRNAs was increased (>2-fold) and of 4 miRNAs was decreased (>50%) in response to PCN, while TCPOBOP treatment led to the up-regulation of 8 miRNAs and down-regulation of 6 miRNAs. Using several miRNA target prediction algorithms, we found that the predicted target genes included several lesser known Cyp genes (Cyp1a1, Cyp1b1, Cyp2b10, Cyp2c38, Cyp2u1, Cyp4a12a/b, Cyp4v3, Cyp17a1, Cyp39a1, and Cyp51). We analyzed the expression of these genes in response to PCN and TCPOBOP and found changes in their mRNA levels, some of which were negatively correlated with the expression of their corresponding miRNAs, suggesting that miRNAs may play a role in regulating Cyp enzyme expression. Further studies will be required to fully elucidate the miRNA regulatory mechanisms that contribute to modulating CYP expression.
authors.affiliation: Department of Biopharmaceutics, Hyogo University of Health Sciences.
authors.forename: Nozomu
authors.initials: N
authors.lastname: Moriya
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kataoka
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Nishikawa
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Kugawa
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000378:metabolism*; D011285:Pregnenolone Carbonitrile / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D035683:MicroRNAs; D011725:Pyridines; D012333:RNA, Messenger; D011285:Pregnenolone Carbonitrile; C028474:1,4-bis(2-(3,5-dichloropyridyloxy))benzene; D003577:Cytochrome P-450 Enzyme System