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https://www.readbyqxmd.com/read/28633424/three-dimensional-3d-heparg-spheroid-model-with-physiologically-relevant-xenobiotic-metabolism-competence-and-hepatocyte-functionality-for-liver-toxicity-screening
#1
Sreenivasa C Ramaiahgari, Suramya Waidyanatha, Darlene Dixon, Michael J DeVito, Richard S Paules, Stephen S Ferguson
Effective prediction of human responses to chemical and drug exposure is of critical importance in environmental toxicology research and drug development. While significant progress has been made to address this challenge using in vitro liver models, these approaches often fail due to inadequate tissue model functionality. Herein, we describe the development, optimization, and characterization of a novel three-dimensional (3D) spheroid model using differentiated HepaRG cells that achieve and maintain physiologically-relevant levels of xenobiotic metabolism (CYP1A2, CYP2B6, and CYP3A4/5)...
June 15, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28624525/regulation-of-hepatic-abcb4-and-cyp3a65-gene-expression-and-multidrug-multixenobiotic-resistance-mdr-mxr-functional-activity-in-the-model-teleost-danio-rerio-zebrafish
#2
Jeremy S Jackson, Christopher J Kennedy
Multidrug/multixenobiotic resistance (MDR/MXR) confers resistance to a diverse range of potentially toxic pharmaceuticals and environmental contaminants through a cellular response that involves the coordinated induction and activity of the ATP-binding cassette (ABC) transporter P-glycoprotein (P-gp) and the Phase I metabolizing enzyme cytochrome P450 3A (CYP3A). In mammals, ligand-mediated pregnane X receptor (PXR) transcriptional activity regulates the induction of P-gp and CYP3A; however, this mechanism has not been well-characterized in fish...
June 14, 2017: Comparative Biochemistry and Physiology. Toxicology & Pharmacology: CBP
https://www.readbyqxmd.com/read/28623334/novel-complex-of-hat-protein-tip60-and-nuclear-receptor-pxr-promotes-cell-migration-and-adhesion
#3
Karishma Bakshi, B Ranjitha, Shraddha Dubey, Jaisri Jagannadham, Bharti Jaiswal, Ashish Gupta
PXR is a member of nuclear receptor superfamily and a well-characterized mediator of xenobiotic metabolism. The classical mode of PXR activation involves its binding to appropriate ligand and subsequent heterodimerization with its partner RXR. However, various factors such as post-translational modifications and crosstalk with different cellular factors may also regulate the functional dynamics and behavior of PXR. In the present study, we have identified that TIP60, an essential lysine acetyltransferase protein interacts with unliganded PXR and together this complex promotes cell migration & adhesion...
June 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28599754/the-effects-of-sex-protein-receptors-and-sex-steroid-hormone-gene-polymorphisms-on-breast-cancer-risk
#4
REVIEW
Somayeh Jahandoost, Pourandokht Farhanghian, Sakineh Abbasi
Breast cancer is a common disease and a major cause of death among women throughout the world. Various genes are believed to be involved in the initiation and progression of the disease. Some polymorphisms of these genes increase susceptibility to breast cancer in particular ethnicities. This study used electronic literature search to review the effects of different sex steroid hormone gene polymorphisms on breast cancer risk. Our findings indicated that some polymorphisms in estrogen receptor alpha (ER-α), ER-β, progesterone receptor (PGR), pregnane X receptor (PXR), and cytochrome P450 enzymes (CYPs) affected breast cancer susceptibility, especially in African American women...
July 2017: Journal of the National Medical Association
https://www.readbyqxmd.com/read/28594304/role-of-vitamin-d-pathway-gene-polymorphisms-on-rifampicin-plasma-and-intracellular-pharmacokinetics
#5
Sarah Allegra, Giovanna Fatiguso, Andrea Calcagno, Lorena Baietto, Ilaria Motta, Fabio Favata, Jessica Cusato, Stefano Bonora, Giovanni Di Perri, Antonio D'Avolio
AIM: We retrospectively evaluate the pharmacogenetic role of single nucleotide polymorphisms involved in rifampicin transport (SLCO1B1, MDR1 and PXR genes) and vitamin D (VDR, CYP24A1 and CYP27B1 genes) metabolism and activity on drug plasma and intracellular concentrations. PATIENTS & METHODS: Rifampicin Cmax and Ctrough were measured at weeks 2 and 4 using Ultra-Performance Liquid Chromatography-tandem mass spectroscopy methods. Allelic discrimination was performed by real-time polymerase chain reaction...
June 8, 2017: Pharmacogenomics
https://www.readbyqxmd.com/read/28575098/mir-148a-mediated-estrogen-induced-cholestasis-in-intrahepatic-cholestasis-of-pregnancy-role-of-pxr-mrp3
#6
Zhou-Zhou Rao, Xiao-Wen Zhang, Yi-Ling Ding, Meng-Yuan Yang
Intrahepatic cholestasis of pregnancy (ICP) is an idiopathic liver disease while the biochemical characteristic is the elevated level of total bile acid (TBA). The present study investigated whether miR-148a mediates the induced effect of estrogen on the development of ICP and the proper mechanism: PXR/MRP3 signal pathway. mRNA expression was detected by qPCR, protein expression was detected by western blotting, the concentration of estrogen and TBA were detected by reagent kit respectively. In the cinical research, it was found that miR-148a expression was positive related with the concentration of TBA in the serum of ICP patients...
2017: PloS One
https://www.readbyqxmd.com/read/28574832/impact-of-chronic-unpredicted-mild-stress-induced-depression-on-repaglinide-fate-via-glucocorticoid-signaling-pathway
#7
Hongyan Wei, Ting Zhou, Boyu Tan, Lei Zhang, Mingming Li, Zhijun Xiao, Feng Xu
Chronic unpredicted mild stress (CUMS)-induced depression could alter the pharmacokinetics of many drugs in rats, however, the underlying mechanism is not clear. In this work we studied the pharmacokinetics of repaglinide, and explored the role of glucocorticoid and adrenergic signaling pathway in regulating drug metabolizing enzymes (DMEs) in GK rats and BRL 3A cells. The plasma cortisol and epinephrine levels were increased, meanwhile the pharmacokinetics of repaglinide were altered significantly in depression model rats...
May 15, 2017: Oncotarget
https://www.readbyqxmd.com/read/28571685/activation-of-the-aryl-hydrocarbon-receptor-decreases-rifampicin-induced-cyp3a4-expression-in-primary-human-hepatocytes-and-heparg
#8
Martin Krøyer Rasmussen, Martine Daujat-Chavanieu, Sabine Gerbal-Chaloin
The role of the cross-talk between nuclear receptors in the regulation of Cytochrome P450 expression in the liver is well-documented. Most studies have focused on the cross-talk between the pregnane X receptor (PXR) and other receptors, such as the constitutive androstane receptor. However, cross-talk between PXRs and aryl hydrocarbon receptors (AhRs) has also been suggested, but reports regarding this cross-talk are conflicting. In the present study, we treated HepaRG and primary human hepatocytes (PHHs) with both a strong (TCDD) and weak (3-methylindole; 3MI) AhR activator to investigate their impact on PXR-regulated expression of CYP3A4...
May 29, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28546421/statins-attenuate-activation-of-the-nlrp3-inflammasome-by-oxidized-ldl-or-tnf-%C3%AE-in-vascular-endothelial-cells-through-a-pxr-dependent-mechanism
#9
Shaolan Wang, Xinya Xie, Ting Lei, Kang Zhang, Baochang Lai, Zihui Zhang, Youfei Guan, Guangmei Mao, Lei Xiao, Nanping Wang
Excessive activation of the NLRP3 inflammasome is implicated in cardiovascular diseases. Statins exert an anti-inflammatory effect independent of their cholesterol lowering effect. This study investigated the potential role of statins in the activation of the NLRP3 inflammasome in endothelial cells (ECs). Western blotting and qRT-PCR showed that oxidized-LDL (oxLDL) or tumor necrosis factor alpha (TNFα) activated the NLRP3 inflammasome in ECs. Simvastatin or mevastatin significantly suppressed the effects of oxLDL or TNFα...
May 25, 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/28546420/alterations-of-histone-modifications-contribute-to-pregnane-x-receptor-mediated-induction-of-cyp3a4-by-rifampicin
#10
Liang Yan, Yiting Wang, Jingyang Liu, Yali Nie, Xiaobo Zhong, Quancheng Kan, Lirong Zhang
Cytochrome P450 3A4 (CYP3A4) is one of the major drug-metabolizing enzymes in human and is responsible for the metabolism of 60% of the clinically used drugs. Many drugs are able to induce the expression of CYP3A4, which usually causes drug-drug interactions and adverse drug reactions. This study aims to explore the role of histone modifications in rifampicin-induced expression of CYP3A4 in LS174T cells. We found that the induction of CYP3A4 mRNA by rifampicin in LS174T cells was associated with increased levels of histone H3 lysine 4 trimethylation (H3K4me3) and H3 acetylation and a decreased level of histone H3 lysine 27 trimethylation (H3K27me3) in the CYP3A4 promoter...
May 25, 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/28541575/xenobiotic-car-activators-induce-dlk1-dio3-locus-non-coding-rna-expression-in-mouse-liver
#11
Lucie Pouché, Antonio Vitobello, Michael Römer, Milica Glogovac, A Kenneth MacLeod, Heidrun Ellinger-Ziegelbauer, Magdalena Westphal, Valérie Dubost, Daniel Philipp Stiehl, Bérengère Dumotier, Alexander Fekete, Pierre Moulin, Andreas Zell, Michael Schwarz, Rita Moreno, Jeffrey T J Huang, Cliff R Elcombe, Colin J Henderson, C Roland Wolf, Jonathan G Moggs, Rémi Terranova
Derisking xenobiotic-induced non-genotoxic carcinogenesis (NGC) represents a significant challenge during the safety assessment of chemicals and therapeutic drugs. The identification of robust mechanism-based NGC biomarkers has the potential to enhance cancer hazard identification. We previously demonstrated Constitutive Androstane Receptor (CAR) and WNT signaling-dependent up-regulation of the pluripotency associated Dlk1-Dio3 imprinted gene cluster non-coding RNAs (ncRNAs) in the liver of mice treated with tumor-promoting doses of phenobarbital (PB)...
May 25, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28534176/functions-of-pregnane-x-receptor-in-self-detoxification
#12
REVIEW
Liuqin He, Xihong Zhou, Niu Huang, Huan Li, Tiejun Li, Kang Yao, Yanan Tian, Chien-An Andy Hu, Yulong Yin
Pregnane X receptor (PXR, NR1I2), a member of the nuclear receptor superfamily, is a crucial regulator of nutrient metabolism and metabolic detoxification such as metabolic syndrome, xenobiotic metabolism, inflammatory responses, glucose, cholesterol and lipid metabolism, and endocrine homeostasis. Notably, much experimental and clinical evidence show that PXR senses xenobiotics and triggers the detoxification response to prevent diseases such as diabetes, obesity, intestinal inflammatory diseases and liver fibrosis...
May 22, 2017: Amino Acids
https://www.readbyqxmd.com/read/28532222/bromuconazole-induced-hepatotoxicity-is-accompanied-by-upregulation-of-pxr-cyp3a1-and-downregulation-of-car-cyp2b1-gene-expression
#13
Doaa H Abdelhadya, Mohammed Abu El-Magd, Zizy I Elbialy, Ayman A Saleh
Despite widespread use of bromuconazole as a pesticide for food crops and fruits, limited studies have been done to evaluate its toxic effects. Here, we evaluated the hepatotoxic effect of bromuconazole using classical toxicological (biochemical analysis and histopathological examination) and gene-based molecular methods. Male rats were treated either orally or topically with bromuconazole at doses equal to no observed adverse effect level (NOAEL) and 1/10 LD50 for 90 d. Bromuconazole increased activities of liver enzymes (ALT, AST, ALP, and ACP), and levels of bilirubin...
June 8, 2017: Toxicology Mechanisms and Methods
https://www.readbyqxmd.com/read/28496040/induction-of-human-cytochrome-p450-3a-enzymes-in-cultured-placental-cells-by-thalidomide-and-relevance-to-bioactivation-and-toxicity
#14
Norie Murayama, Yasuhiro Kazuki, Daisuke Satoh, Kazuya Arata, Tasuku Harada, Norio Shibata, F Peter Guengerich, Hiroshi Yamazaki
Evidence has been presented for auto-induced human cytochrome P450 3A enzyme involvement in the teratogenicity and clinical outcome of thalidomide due to oxidation to 5-hydroxythalidomide and subsequent metabolic activation in livers. In this study, more relevant human placenta preparations and placental BeWo cells showed low but detectable P450 3A4/5 mRNA expression and drug oxidation activities. Human placental microsomal fractions from three subjects showed detectable midazolam 1´- and 4-hydroxylation and thalidomide 5-hydroxylation activities...
2017: Journal of Toxicological Sciences
https://www.readbyqxmd.com/read/28495613/mode-of-action-and-human-relevance-of-thf-induced-mouse-liver-tumors
#15
Christopher J Choi, Erik K Rushton, Audrey Vardy, Larry Higgins, Andrea Augello, Ralph J Parod
In a National Toxicology Program (NTP) bioassay, inhalation of tetrahydrofuran (THF) induced liver tumors in female B6C3F1 mice but not in male mice or rats of either sex. Since THF is not genotoxic, the NTP concluded this carcinogenic activity was likely mediated via non-genotoxic modes of action (MOA). Based on evidence that THF and phenobarbital share a similar MOA, female Car/Pxr knock-out mice were orally exposed to THF to evaluate the potential role of CAR activation in the MOA for THF-induced liver tumors...
July 5, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28489504/validation-of-the-cell-line-ls180-as-a-model-for-study-of-the-gastrointestinal-toxicity-of-mycophenolic-acid
#16
Svenja Heischmann, Uwe Christians
1. Gastrointestinal (GI) intolerability is a concern for drugs such as mycophenolic acid (MPA) and drug metabolism may play a role. Few in vitro models exist that allow for the preclinical evaluation of a potential role of drug metabolism in intestinal drug toxicity. Thus, we sought to develop an in vitro model based on the human colon adenocarcinoma cell line LS180 to investigate MPA's negative effects on intestinal cells. 2. Stability of expression of key enzymes of MPA metabolism (UGT1A7, UGT1A9, UGT1A10, UGT2B7, CYP3A4 and CYP3A5), transporters (OATP1B1, OATP1B3, OATP2B1, MRP1, MRP2 and MDR1) and the nuclear receptor PXR over 12 passages in combination with guanosine supplementation to counter MPA's antiproliferative effects (determined by western blot analysis and proliferation assays, respectively) was established...
May 30, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/28470937/endothelial-cell-derived-matrix-promotes-the-metabolic-functional-maturation-of-hepatocyte-via-integrin-src-signalling
#17
Xinyue Guo, Weihong Li, Minghui Ma, Xin Lu, Haiyan Zhang
The extracellular matrix (ECM) microenvironment is involved in the regulation of hepatocyte phenotype and function. Recently, the cell-derived extracellular matrix has been proposed to represent the bioactive and biocompatible materials of the native ECM. Here, we show that the endothelial cell-derived matrix (EC matrix) promotes the metabolic maturation of human adipose stem cell-derived hepatocyte-like cells (hASC-HLCs) through the activation of the transcription factor forkhead box protein A2 (FOXA2) and the nuclear receptors hepatocyte nuclear factor 4 alpha (HNF4α) and pregnane X receptor (PXR)...
May 4, 2017: Journal of Cellular and Molecular Medicine
https://www.readbyqxmd.com/read/28468837/crypt-organoid-culture-as-an-in-vitro-model-in-drug-metabolism-and-cytotoxicity-studies
#18
Wenqi Lu, Eva Rettenmeier, Miles Paszek, Mei-Fei Yueh, Robert H Tukey, Jocelyn Trottier, Olivier Barbier, Shujuan Chen
The gastrointestinal tract is enriched with xenobiotic processing proteins that play important roles in xenobiotic bioactivation, metabolism, and detoxification. The application of genetically modified mouse models has been instrumental in characterizing the function of xenobiotic processing genes (XPG) and their proteins in drug metabolism. Here, we report the utilization of three-dimensional crypt organoid cultures from these animal models to study intestinal drug metabolism and toxicity. With the successful culturing of crypt organoids, we profiled the abundance of Phase I and Phase II XPG expression, drug transporter gene expression, and xenobiotic nuclear receptor (XNR) gene expression...
July 2017: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/28442602/molecular-basis-of-metabolism-mediated-conversion-of-pk11195-from-an-antagonist-to-an-agonist-of-the-constitutive-androstane-receptor
#19
Bryan Mackowiak, Linhao Li, Matthew A Welch, Daochuan Li, Jace W Jones, Scott Heyward, Maureen A Kane, Peter W Swaan, Hongbing Wang
The constitutive androstane receptor (CAR) plays an important role in xenobiotic metabolism, energy homeostasis, and cell proliferation. Antagonism of the CAR represents a key strategy for studying its function and may have potential clinical applications. However, specific human CAR (hCAR) antagonists are limited and conflicting data on the activity of these compounds have been reported. 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide (PK11195), a typical peripheral benzodiazepine receptor ligand, has been established as a potent hCAR deactivator in immortalized cells; whether it inhibits hCAR activity under physiologically relevant conditions remains unclear...
July 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/28436464/glucose-dependent-regulation-of-pregnane-x-receptor-is-modulated-by-amp-activated-protein-kinase
#20
Peter O Oladimeji, Wenwei Lin, C Trent Brewer, Taosheng Chen
Pregnane X receptor (PXR) is a xenobiotic receptor that regulates the detoxification and clearance of drugs and foreign compounds from the liver. There has been mounting evidence of crosstalk between the drug metabolism pathway and the energy metabolism pathway, but little is known about this cross-regulation. To further delineate the energy metabolism and drug metabolism crosstalk in this study, we exposed HepG2 cells to varying glucose concentrations. We observed that PXR activity was induced under high-glucose conditions...
April 24, 2017: Scientific Reports
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