Genome-wide analysis of human constitutive androstane receptor (CAR) transcriptome in wild-type and CAR-knockout HepaRG cells.
The constitutive androstane receptor (CAR) modulates the transcription of numerous genes involving drug metabolism, energy homeostasis, and cell proliferation. Most functions of CAR however were defined from animal studies. Given the known species difference of CAR and the significant cross-talk between CAR and the pregnane X receptor (PXR), it is extremely difficult to decipher the exact role of human CAR (hCAR) in gene regulation, relying predominantly on pharmacological manipulations. Here, utilizing a newly generated hCAR-knockout (KO) HepaRG cell line, we carried out RNA-seq analysis of the global transcriptomes in wild-type (WT) and hCAR-KO HepaRG cells treated with CITCO, a selective hCAR agonist, phenobarbital (PB), a dual activator of hCAR and hPXR, or vehicle control. Real-time PCR assays in separate experiments were used to validate RNA-seq findings. Our results indicate that genes encoding drug-metabolizing enzymes are among the main clusters altered by both CITCO and PB. Specifically, CITCO significantly changed the expression of 135 genes in an hCAR-dependent manner, while PB altered the expression of 227 genes in WT cells of which 94 were simultaneously modulated in both cell lines reflecting dual effects of PB on hCAR/PXR. Notably, we found that many genes promoting cell proliferation and tumorigenesis were up-regulated in hCAR-KO cells, suggesting that hCAR may play an important role in cell growth that differs from mouse CAR. Together, our results reveal both novel and known targets of hCAR and support the role of hCAR in maintaining the homeostasis of metabolism and cell proliferation in the liver.
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, United States.
Daochuan
D
Li
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, United States.
Bryan
B
Mackowiak
Sigma Life Sciences, 2909 Laclede Ave, St. Louis, MO 63103, United States.
Timothy G
TG
Brayman
Sigma Life Sciences, 2909 Laclede Ave, St. Louis, MO 63103, United States.
Michael
M
Mitchell
Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20901, United States.
Lei
L
Zhang
Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20901, United States.
Shiew-Mei
SM
Huang
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, United States. Electronic address: hwang@rx.umaryland.edu.
Hongbing
H
Wang
D000090702:Constitutive Androstane Receptor; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D017353:Gene Deletion; D005786:Gene Expression Regulation / Q000502:physiology; D055106:Genome-Wide Association Study; D006801:Humans; D010091:Oximes / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D013844:Thiazoles / Q000494:pharmacology; D059467:Transcriptome
D000090702:Constitutive Androstane Receptor; D018691:Excitatory Amino Acid Antagonists; D010091:Oximes; D018160:Receptors, Cytoplasmic and Nuclear; D013844:Thiazoles; C475093:6-(4-chlorophenyl)imidazo(2,1-b)(1,3)thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime; D010634:Phenobarbital
CAR; CITCO; Gene knockout; HepaRG; Phenobarbital; RNA-seq