title: Characterizing drug-metabolizing enzymes and transporters that arebona fideCAR-target genes in mouse intestine.
abstract: Intestine is responsible for the biotransformation of many orally-exposed chemicals. The constitutive androstane receptor (CAR/Nr1i3) is known to up-regulate many genes encoding drug-metabolizing enzymes and transporters (drug-processing genes/DPGs) in liver, but less is known regarding its effect in intestine. Sixty-day-old wild-type andCar-/-mice were administered the CAR-ligand TCPOBOP or vehicle once daily for 4 days. In wild-type mice,CarmRNA was down-regulated by TCPOBOP in liver and duodenum.Car-/-mice had altered basal intestinal expression of many DPGs in a section-specific manner. Consistent with the liver data (Aleksunes and Klaassen, 2012), TCPOBOP up-regulated many DPGs (Cyp2b10, Cyp3a11, Aldh1a1, Aldh1a7, Gsta1, Gsta4, Gstm1-m4, Gstt1, Ugt1a1, Ugt2b34, Ugt2b36, andMrp2-4) in specific sections of small intestine in a CAR-dependent manner. However, the mRNAs ofNqo1andPapss2were previously known to be up-regulated by TCPOBOP in liver but were not altered in intestine. Interestingly, many known CAR-target genes were highest expressed in colon where CAR is minimally expressed, suggesting that additional regulators are involved in regulating their expression. In conclusion, CAR regulates the basal expression of many DPGs in intestine, and although many hepatic CAR-targeted DPGs werebona fideCAR-targets in intestine, pharmacological activation of CAR in liver and intestine are not identical.
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.
authors.forename: Shinhee
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.
authors.forename: Sunny Lihua
authors.initials: SL
authors.lastname: Cheng
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.
authors.forename: Julia Yue
authors.initials: JY
authors.lastname: Cui
keywords: Aldh, aldehyde dehydrogenase; Asbt, solute carrier family 10, member 2 (apical sodium/bile acid cotransporter); CAR; CAR, constitutive androstane receptor; CITCO, 6-(4-chlorophenyl)imidazo [2,1-b](1,3)thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime; Cq, quantification cycle; Cyp, cytochrome P450; DPGs, drug-processing genes (genes that encodes drug metabolizing enzymes or transporters); Drug-metabolizing enzymes; Drug-processing genes; Gst, glutathione S-trasnferase; H3, Histone 3; HRP, horseradish peroxidase; Intestine; Mice; Mrp, multi-drug resistance-associated protein (ABC transporter family C member); Nqo1, NAD(P)H dehydrogenase quinone 1; Nrf2, nuclear factor erythroid 2-related factor 2; Oatp, organic anion transporting polypeptide (solute carrier organic anion transporter family member); PBS, phosphate-buffered saline; PBST, phosphate-buffered saline with 0.05% tween 20; PPARα, peroxisome proliferator activated receptor alpha; PVDF, polyvinylidene difluoride; Papss2, 3ʹ-phosphoadenosine 5ʹ-phosphosulfate synthase 2; ST buffer, sucrose Tris buffer; Sult, sulfotransferase; TCPOBOP, 3,3ʹ,5,5ʹ-tetrachloro-1,4-bis(pyridyloxy)benzene; Transporters; Ugt, UDP glucuronosyltransferase; WT, wild-type; cDNA, complementary DNA; ddCq, delta delta Cq; hCAR, human constitutive androstane receptor; qPCR, quantitative polymerase chain reaction