Project description:To identify the CAR-, PXR- and PPARα-specific genome-wide expression changes, hepatocyte cultures from six individual donors were treated with the prototypical ligands for CAR (CITCO), PXR (rifampicin) and PPARα (WY14,643) as well as DMSO (vehicle control). Afterwards, the mRNA expression in these samples was determined utilizing Affymetrix® microarrays. Primary human hepatocytes (PHH) from 6 donors were treated for 24 h with 10µM of rifampicin, 50µM of WY14,643, 1µM of CITCO and 0.1% of DMSO (vehicle).
Project description:To identify the CAR-, PXR- and PPARα-specific genome-wide expression changes, hepatocyte cultures from six individual donors were treated with the prototypical ligands for CAR (CITCO), PXR (rifampicin) and PPARα (WY14,643) as well as DMSO (vehicle control). Afterwards, the mRNA expression in these samples was determined utilizing Affymetrix® microarrays.
Project description:In primary human hepatocytes (PHH) the involvement of the Pregnane X Receptor (PXR) in genes regulations by Phenobarbital (PB) has never been evaluated at the transcriptomic level. Here we investigated the impact of PXR depletion and epidermal growth factor on PXR dependent gene modulation by PB in PHH. The potential crosstalk with CAR was investigated using Phenobarbital and the direct CAR activator (CITCO) in presence or in absence of EGF.
Project description:The nuclear receptors CAR (constitutive androstane receptor) and PXR (pregnane X receptor) mediate the effects of phenobarbital (PB) on gene transcription. To investigate the relative role of CAR and PXR in the induction response, cDNA arrays were generated containing 120 genes which are known to be regulated with these or related nuclear receptors (genes involved in drug metabolism, cholesterol biosynthesis, sterol synthesis/transport, heme synthesis). Samples from livers of wild type and CAR-/-, PXR-/- or CAR/PXR-/- knockout mice were tested after treatment with PB for gene expression within the European Framework V program “Steroltalk” (www.steroltalk.net). Results from these experiments unexpectedly revealed that if CAR and PXR are deleted, PB increases the expression of several other nuclear receptors and genes involved in drug metabolism and cholesterol biosynthesis. Animals were injected i.p. 100mg/kg phenobarbital or vehicle (5% DMSO in corn oil). After 12h they were sacrificed and total RNA was isolated from the livers. Pools of untreated samples were mixed in each genetic variant group (wild type and CAR-/-, PXR-/- or CAR/PXR-/-) with the phenobarbital treated ones and hybridized to Sterolgene V1 arrays.
Project description:Purpose: The goal of this study was to investigate how PBDEs regulate both PCGs and lncRNAs in a PXR/CAR ligand-dependent and independent manner Methods: HepaRG cells, which are human-derived hepatic cells that accurately represent gene expression profiles of human liver tissue, were exposed to BDE-47 and BDE-99 at a dose of 25 μM for 24 hours. Differentially expressed lncRNA-PCG pairs were identified through DESeq2 and HOMER; significant canonical pathways were determined through Ingenuity Pathway Analysis (IPA). LncTar was used to predict the binding of 19 lncRNA-PCG pairs with known roles in drug-processing pathways. Results: Genome annotation revealed that the majority of the differentially expressed lncRNAs map to PCG introns. PBDEs regulated overlapping pathways with PXR and CAR such as protein ubiqutination pathway and peroxisome proliferator-activated receptor alpha-retinoid X receptor alpha (PPARα-RXRα) activation but also regulate distinctive pathways involved in intermediary metabolism. PBDEs uniquely down-regulated GDP-L-fucose biosynthesis, suggesting its role in modifying important pathways involved in intermediary metabolism such as carbohydrate and lipid metabolism. Conclusion: There is strong evidence that PBDEs regulate both PCGs and lncRNAs in a PXR/CAR ligand-dependent and independent manner
Project description:The nuclear receptor PXR (Pregnane X rreceptor) mediates the effects of pregnenolone-16alpha-carbonitrile (PCN) on gene transcription. The relative role of PXR and also CAR to the induction response by PCN was studied on cDNA arrays containing 320 (Steroltalk V2) genes (genes involved in cyrcadian rhythm, drug metabolism, cholesterol biosynthesis, sterol synthesis/transport, heme synthesis). Samples from livers of wild type and CAR-/-, PXR-/- or CAR/PXR-/- knockout mice were tested after treatment with PCN for gene expression within the European Framework V program âSteroltalkâ (www.steroltalk.net). Results from these experiments show the complex role of PXR receptor in the expression of genes involved in cyrcadian rhythm, drug metabolism and cholesterol biosynthesis. Animals were injected i.p. 40mg/kg PCN or vehicle (5% DMSO in corn oil). After 12h they were sacrificed and total RNA was isolated from the livers. Pools of untreated samples were mixed in each genetic variant group (wild type and CAR-/-, PXR-/- or CAR/PXR-/-) with the PCN treated ones and hybridized to Steroltalk V2 arrays.
Project description:The nuclear receptor CAR (constitutive androstane receptor) mediates the effects of 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) on gene transcription. To investigate the relative role of CAR and also PXR in the induction response, cDNA arrays were generated containing 120 (Sterolgene V1) genes which are known to be regulated with these or related nuclear receptors (genes involved in drug metabolism, cholesterol biosynthesis, sterol synthesis/transport, heme synthesis). Samples from livers of wild type and CAR-/-, PXR-/- or CAR/PXR-/- knockout mice were tested after treatment with TCPOBOP for gene expression within the European Framework V program “Steroltalk” (www.steroltalk.net). Results from these experiments show the complex role of CAR receptor in the expression of genes involved in drug metabolism and cholesterol biosynthesis. Animals were injected i.p. 10mg/kg TCPOBOP or vehicle (5% DMSO in corn oil). After 12h they were sacrificed and total RNA was isolated from the livers. Pools of untreated samples were mixed in each genetic variant group (wild type and CAR-/-, PXR-/- or CAR/PXR-/-) with the TCPOBOP treated ones and hybridized to Sterolgene V1 arrays.
Project description:Viruses lack the basic machinery needed to replicate and therefore must hijack host metabolism to propagate. Virus-induced metabolic alterations have yet to be systematically studied in the context of the host transcriptional regulation, offering insight into host-pathogen metabolic interplay. In this work we identified Hepatitis C Virus (HCV)-responsive regulators by coupling system-wide metabolic flux analysis with targeted perturbation of nuclear receptors in primary human hepatocytes. We find HCV-induced up-regulation of glycolysis, ketogenesis and drug metabolism, controlled by activation of HNF4α, PPARα, FXR and PXR, respectively. Pharmaceutical inhibition of HNF4α reversed HCV-induced glycolysis, blocking viral replication while increasing apoptosis in infected cells showing a viral-induced dependence on glycolysis. In contrast, pharmaceutical inhibition of PPARα or FXR reversed HCV-induced ketogenesis, but increased viral replication demonstrating a unique host anti-viral response. Our results show that viral-induced changes to host metabolism can be detrimental to its lifecycle demonstrating a distinct biological complexity. In this dataset, we include the expression data obtained from primary human hepatocyte oxygenated co-cultures infected or not infected by HCV and human sanp frozen liver biopsys from HCV patients at earley stages.
Project description:The constitutive androstane receptor (CAR) and the pregnane X receptor (PXR) are closely related nuclear receptors involved in drug metabolism and play important roles in the mechanism of phenobarbital (PB)-induced rodent nongenotoxic hepatocarcino- genesis. Here, we have used a humanized CAR/PXR mouse model to examine potential species differences in receptor-dependent mechanisms underlying liver tissue molecular responses to PB. Early and late transcriptomic responses to sustained PB exposure were investigated in liver tissue from double knock-out CAR and PXR (CARKO -PXRKO ), double humanized CAR and PXR (CARh - PXRh), and wild-type C57BL/6 mice. Wild-type and CARh-PXRh mouse livers exhibited temporally and quantitatively similar tran- scriptional responses during 91 days of PB exposure including the sustained induction of the xenobiotic response gene Cyp2b10, the Wnt signaling inhibitor Wisp1, and noncoding RNA biomarkers from the Dlk1-Dio3 locus. Transient induction of DNA replication (Hells, Mcm6, and Esco2) and mitotic genes (Ccnb2, Cdc20, and Cdk1) and the proliferation-related nuclear antigen Mki67 were ob- served with peak expression occurring between 1 and 7 days PB ex- posure. All these transcriptional responses were absent in CARKO- PXRKO mouse livers and largely reversible in wild-type and CARh - PXRh mouse livers following 91 days of PB exposure and a subse- quent 4-week recovery period. Furthermore, PB-mediated upregu- lation of the noncoding RNA Meg3, which has recently been associ- ated with cellular pluripotency, exhibited a similar dose response and perivenous hepatocyte-specific localization in both wild-type and CARh-PXRh mice. Thus, mouse livers coexpressing human CAR and PXR support both the xenobiotic metabolizing and the proliferative transcriptional responses following exposure to PB. 13-week oral (drinking water) investigative phenobarbital study in male C57BL/6 wild type, CAR/PXR knockout and humanized CAR/PXR mice with a 4 week recovery period
Project description:The constitutive androstane receptor (CAR) and the pregnane X receptor (PXR) are closely related nuclear receptors involved in drug metabolism and play important roles in the mechanism of phenobarbital (PB)-induced rodent nongenotoxic hepatocarcino- genesis. Here, we have used a humanized CAR/PXR mouse model to examine potential species differences in receptor-dependent mechanisms underlying liver tissue molecular responses to PB. Early and late transcriptomic responses to sustained PB exposure were investigated in liver tissue from double knock-out CAR and PXR (CARKO -PXRKO ), double humanized CAR and PXR (CARh - PXRh), and wild-type C57BL/6 mice. Wild-type and CARh-PXRh mouse livers exhibited temporally and quantitatively similar tran- scriptional responses during 91 days of PB exposure including the sustained induction of the xenobiotic response gene Cyp2b10, the Wnt signaling inhibitor Wisp1, and noncoding RNA biomarkers from the Dlk1-Dio3 locus. Transient induction of DNA replication (Hells, Mcm6, and Esco2) and mitotic genes (Ccnb2, Cdc20, and Cdk1) and the proliferation-related nuclear antigen Mki67 were ob- served with peak expression occurring between 1 and 7 days PB ex- posure. All these transcriptional responses were absent in CARKO- PXRKO mouse livers and largely reversible in wild-type and CARh - PXRh mouse livers following 91 days of PB exposure and a subse- quent 4-week recovery period. Furthermore, PB-mediated upregu- lation of the noncoding RNA Meg3, which has recently been associ- ated with cellular pluripotency, exhibited a similar dose response and perivenous hepatocyte-specific localization in both wild-type and CARh-PXRh mice. Thus, mouse livers coexpressing human CAR and PXR support both the xenobiotic metabolizing and the proliferative transcriptional responses following exposure to PB. 13-week oral (drinking water) investigative phenobarbital study in male C57BL/6 wild type, CAR/PXR knockout and humanized CAR/PXR mice with a 4 week recovery period