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https://www.readbyqxmd.com/read/29046637/meclizine-prevents-ovariectomy-induced-bone-loss-and-inhibits-osteoclastogenesis-partially-by-upregulating-pxr
#1
Jiachao Guo, Weijin Li, Yingxing Wu, Xingzhi Jing, Junming Huang, Jiaming Zhang, Wei Xiang, Ranyue Ren, Zhengtao Lv, Jun Xiao, Fengjing Guo
Pregnane X receptor (PXR) which belongs to the nuclear hormone receptor superfamily plays vital roles in several biological functions, especially in the inflammatory procedure. Besides that, PXR is revealed by recent studies to have essential effects on bone tissue. As an agonist of PXR, meclizine is a piperazine-derived histamine H1 antagonist, and has been frequently used for prevention and treatment of vomiting and nausea. Because osteoclastogenesis is characterized by the activation of inflammation-related signaling pathways, we speculated that meclizine may affect formation and function of osteoclast...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29030272/impact-of-fasting-followed-by-short-term-exposure-to-interleukin-6-on-cytochrome-p450-mrna-in-mice
#2
Martin Krøyer Rasmussen, Lærke Bertholdt, Anders Gudiksen, Henriette Pilegaard, Jakob G Knudsen
mRNA expression of the cytochrome P450 (CYP) enzyme family is regulated by numerous factors. Fasting has been shown to induce increased hepatic CYP mRNA in both humans and animals. However, the coordinated regulation of CYP, CYP-regulating transcription factors, and transcriptional co-factors in the liver linking energy metabolism to detoxification has never been investigated. Interleukin-6 (IL-6) has been suggested to be released during fasting and has been shown to regulate CYP expression. The present study investigated the mRNA content of selected CYP, AhR, CAR, PXR and PPARα in mice fasted for 18hours and subsequently exposed to IL-6...
October 10, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/29027256/integrated-in-silico-and-in-vivo-approaches-to-investigate-effects-of-bde-99-mediated-by-the-nuclear-receptors-on-developing-zebrafish
#3
Li Zhang, Yaru Jin, Zhihua Han, Hongling Liu, Laihao Shi, Xiaoxue Hua, Jon A Doering, Song Tang, John P Giesy, Hongxia Yu
BDE-99 is one of the most abundant PBDEs, which due to its potential persistence and bioaccumulation occurs in aquatic wildlife. Previous studies in mammals have shown that BDE-99 affected development and disrupted certain endocrine functions through signaling pathways mediated by nuclear receptors (NRs). However, fewer studies have investigated the potential of BDE-99 to interact with NRs in aquatic vertebrates, such as fish. In the present study, interactions between BDE-99 and NRs were investigated by use of in silico and in vivo approaches...
October 12, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/29016144/alismanin-a-a-triterpenoid-with-a-c34-skeleton-from-alisma-orientale-as-a-natural-agonist-of-human-pregnane-x-receptor
#4
Chao Wang, Xiao-Kui Huo, Zhi-Lin Luan, Fei Cao, Xiang-Ge Tian, Xin-Yu Zhao, Cheng-Peng Sun, Lei Feng, Jing Ning, Bao-Jing Zhang, Xiao-Chi Ma
Alismanin A (1), a novel aromatic triterpenoid with a C34 skeleton, was isolated from Alisma orientale together with a rearranged nor-triterpenoid (2) and a 13,17-seco triterpenoid (3). Their structures were determined by a combination of HRESIMS, 2D NMR spectra, electronic circular dichroism (ECD), theoretical calculations, and X-ray diffraction analysis. Compounds 1 and 2 displayed significant activation effects on pregnane X receptor (PXR) at 10 nM. A plausible biosynthetic pathway for 1-3 is also discussed...
October 10, 2017: Organic Letters
https://www.readbyqxmd.com/read/28970358/xenobiotic-nuclear-receptors-pxr-and-car-regulate-antiretroviral-drug-efflux-transporters-at-the-blood-testis-barrier
#5
Sana-Kay Whyte-Allman, Md Tozammel Hoque, Mohammad-Ali Jenabian, Jean-Pierre Routy, Reina Bendayan
Poor antiretroviral drug (ARV) penetration in the testes could, in part, be due to the presence of ATP-binding cassette membrane-associated drug efflux transporters such as P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated proteins (MRPs) expressed at the blood-testis barrier (BTB). The functional expression of these transporters is known to be regulated by ligand-activated nuclear receptors, pregnane X receptor (PXR) and constitutive androstane receptor (CAR), in various tissues...
September 28, 2017: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/28968576/rna-sequencing-indicates-that-atrazine-induces-multiple-detoxification-genes-in-daphnia-magna-and-this-is-a-potential-source-of-its-mixture-interactions-with-other-chemicals
#6
Allison M Schmidt, Namrata Sengupta, Christopher A Saski, Rooksana E Noorai, William S Baldwin
Atrazine is an herbicide with several known toxicologically relevant effects, including interactions with other chemicals. Atrazine increases the toxicity of several organophosphates and has been shown to reduce the toxicity of triclosan to D. magna in a concentration dependent manner. Atrazine is a potent activator in vitro of the xenobiotic-sensing nuclear receptor, HR96, related to vertebrate constitutive androstane receptor (CAR) and pregnane X-receptor (PXR). RNA sequencing (RNAseq) was performed to determine if atrazine is inducing phase I-III detoxification enzymes in vivo, and estimate its potential for mixture interactions...
September 25, 2017: Chemosphere
https://www.readbyqxmd.com/read/28968417/effects-of-meal-composition-and-meal-timing-on-the-expression-of-genes-involved-in-hepatic-drug-metabolism-in-rats
#7
E M de Vries, J E Oosterman, H M Eggink, P de Goede, S Sen, E Foppen, O Boudzovitch-Surovtseva, A Boelen, J A Romijn, S E laFleur, A Kalsbeek
INTRODUCTION: With chronotherapy, drug administration is synchronized with daily rhythms in drug clearance and pharmacokinetics. Daily rhythms in gene expression are centrally mastered by the suprachiasmatic nucleus of the hypothalamus as well as by tissue clocks containing similar molecular mechanisms in peripheral organs. The central timing system is sensitive to changes in the external environment such as those of the light-dark cycle, meal timing and meal composition. We investigated how changes in diet composition and meal timing would affect the daily hepatic expression rhythms of the nuclear receptors PXR and CAR and of enzymes involved in P450 mediated drug metabolism, as such changes could have consequences for the practice of chronotherapy...
2017: PloS One
https://www.readbyqxmd.com/read/28949776/beneficial-effects-of-bile-acid-receptor-agonists-in-pulmonary-disease-models
#8
Paolo Comeglio, Annamaria Morelli, Luciano Adorini, Mario Maggi, Linda Vignozzi
Bile acids act as steroid hormones, controlling lipid, glucose and energy metabolism, as well as inflammation and fibrosis. Their actions are implemented through activation of nuclear (FXR, VDR, PXR) and membrane G protein-coupled (TGR5, S1PR2) receptors. Areas covered: This review discusses the potential of FXR and TGR5 as therapeutic targets in the treatment of pulmonary disorders linked to metabolism and/or inflammation. Obeticholic acid (OCA) is the most clinically advanced bile acid-derived agonist for FXR-mediated anti-inflammatory and anti-fibrotic effects...
November 2017: Expert Opinion on Investigational Drugs
https://www.readbyqxmd.com/read/28945086/oleanolic-acid-mediated-inhibition-of-pregnane-x-receptor-and-constitutive-androstane-receptor-attenuates-rifampin-isoniazid-cytotoxicity
#9
Yen-Ning Lin, Chao-Jung Chen, Hsiao-Yun Chang, Wai-Kok Cheng, Ying-Ray Lee, Jih-Jung Chen, Yun-Ping Lim
Interactions between transcriptional inducers of cytochrome P450 (CYP450) and pharmacological agents might decrease drug efficacy and induce side effects. Such interactions could be prevented using an antagonist of the pregnane X receptor (PXR) and constitutive androstane receptor (CAR). Here, we aimed to determine the antagonistic effect of oleanolic acid (OA) on PXR and CAR. OA attenuated the promoter activities, expressions, and enzyme catalytic activities of CYP3A4 and CYP2B6 mediated by rifampin (RIF) and CITCO...
September 25, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28942083/intracellular-localization-of-pregnane-x-receptor-in-hepg2-cells-cultured-by-the-hanging-drop-method
#10
Kosuke Yokobori, Kaoru Kobayashi, Ikuko Azuma, Hidetaka Akita, Kan Chiba
Pregnane X receptor (PXR) is localized in the cytoplasm of liver cells, whereas it is localized in the nucleus of monolayer-cultured HepG2 cells. Since cultured cells are affected by the microenvironment in which they are grown, we studied the effect of three-dimensional (3D) culture on the localization of PXR in HepG2 cells using the hanging drop method. The results showed that PXR was retained in the cytoplasm of HepG2 cells and other human hepatocarcinoma cell lines (FLC5, FLC7 and Huh7) when they were cultured by the hanging drop method...
August 26, 2017: Drug Metabolism and Pharmacokinetics
https://www.readbyqxmd.com/read/28941036/association-of-donor-sumo4-rs237025-genetic-variant-with-tacrolimus-elimination-in-the-early-period-after-liver-transplantation
#11
Tao Zhang, Yuan Liu, Rong Zeng, Qi Ling, Peihao Wen, Junwei Fan, Zhihai Peng
BACKGROUNDS & AIMS: Individualized tacrolimus treatment can improve drug safety and efficacy. In this study, we aimed to investigate the association of donor and recipient small ubiquitin-like modifier 4 (SUMO4) rs237025 polymorphisms with tacrolimus elimination and the potential mechanism. METHODS: A total of 297 liver transplant patients were enrolled in the study. CYP3A5 rs776746 and SUMO4 rs237025 were genotyped using TaqMan SNPs assays. The activity of nuclear factor-kB (NF-kB) was evaluated by luciferase assay...
September 21, 2017: Liver International: Official Journal of the International Association for the Study of the Liver
https://www.readbyqxmd.com/read/28939253/heterodimerization-of-retinoid-x-receptor-with-xenobiotic-receptor-partners-occurs-in-the-cytoplasmic-compartment-mechanistic-insights-of-events-in-living-cells
#12
Amit K Dash, Ashutosh S Yende, Bharti Jaiswal, Rakesh K Tyagi
Retinoid X Receptor (RXR) serves as the heterodimeric partner of two major xenobiotic nuclear receptors, Pregnane and Xenobiotic Receptor (PXR) and Constitutive Androstane Receptor (CAR). These receptors are primarily involved in the metabolism and clearance of endobiotics and xenobiotics (including clinical drugs) from the body. Here, we report for the first time that intermolecular interactions between RXR-PXR and RXR-CAR occurs in the cytoplasmic compartment of the cell in a ligand-independent manner. These interactions lead to nuclear import of the heterodimeric complex thereby making them competent for chromatin binding and transactivation of target genes...
September 20, 2017: Experimental Cell Research
https://www.readbyqxmd.com/read/28927887/epidermal-overexpression-of-xenobiotic-receptor-pxr-impairs-the-epidermal-barrier-and-triggers-th2-immune-response
#13
Andreas Elentner, Matthias Schmuth, Nikolaos Yannoutsos, Thomas O Eichmann, Robert Gruber, Franz Pw Radner, Martin Hermann, Barbara Del Frari, Sandrine Dubrac
The skin is in daily contact with environmental pollutants, but the long-term effects of such exposure remain under-investigated. Many of these toxins bind and activate the pregnane x receptor (PXR), a ligand-activated transcription factor that regulates genes central to xenobiotic metabolism. The objective of this work was to investigate the effect of constitutive activation of PXR in the basal layer of the skin to mimic repeated skin exposure to noxious molecules. We designed a transgenic mouse model which overexpresses the human PXR gene linked to the herpes simplex VP16 domain under the control of the keratin 14 promoter...
September 16, 2017: Journal of Investigative Dermatology
https://www.readbyqxmd.com/read/28920616/vitamin-c-protects-piglet-liver-against-zearalenone-induced-oxidative-stress-by-modulating-expression-of-nuclear-receptors-pxr-and-car-and-their-target-genes
#14
Baoming Shi, Yang Su, Siying Chang, Yuchen Sun, Xiangyu Meng, Anshan Shan
Zearalenone (ZEN), one of the most common mycotoxins found in human food and animal feed, has been shown to be effectively detoxified by vitamin C (Vc). The aim of this study was to investigate how vitamin C protects the piglet liver against oxidative stress induced by ZEN. A total of thirty-two healthy female crossbred weaning piglets (Duroc × Landrace × Large white) with an initial weight of 12.27 ± 0.30 kg were randomly divided into four treatment groups of eight piglets per group. The dietary treatments included two zearalenone levels (0 mg kg(-1) and 1...
September 18, 2017: Food & Function
https://www.readbyqxmd.com/read/28916285/profiling-of-bisphenol-s-towards-nuclear-receptors-activities-in-human-reporter-cell-lines
#15
Ondrej Zenata, Zdenek Dvorak, Radim Vrzal
Bisphenol S (BPS) is heat-stable structural analog of bisphenol A (BPA), a known endocrine disruptor. Due to the effort to replace BPA with BPS, it is essential to know if BPS is suitable non-toxic replacement without reported deleterious effects of BPA. Since most of the BPA effects are ascribed to its ability to activate nuclear receptors, we screened some prominent members of this family in order to confirm or refute some recent findings. We found that BPS insignificantly activated aryl hydrocarbon receptor (AhR) in reporter gene assay and no induction of AhR target gene CYP1A1 was observed in human hepatocytes (HH)...
September 12, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28911860/glucose-elicits-serine-threonine-kinase-vrk1-to-phosphorylate-nuclear-pregnane-x-receptor-as-a-novel-hepatic-gluconeogenic-signal
#16
Saki Gotoh, Yuu Miyauchi, Rick Moore, Masahiko Negishi
Low glucose stimulated phosphorylation of pregnane X receptor (PXR) at Ser(350) in correlation with an increased gluconeogenesis in human hepatoma-derived HepG2 cells. Only glucose, but neither insulin nor glucagon, stimulated this phosphorylation. Here, serine/threonine kinase, vaccinia related kinase 1 (VRK1)-mediated phosphorylation of PXR is now defined as this glucose-elicited novel signal. In low glucose conditions, VRK1 directly phosphorylates PXR at Ser(350), enabling PO3-PXR to scaffold protein phosphatase PP2Cα...
September 12, 2017: Cellular Signalling
https://www.readbyqxmd.com/read/28888833/iron-depletion-induces-hepatic-secretion-of-biliary-lipids-and-glutathione-in-rats
#17
Alena Prasnicka, Jolana Cermanova, Milos Hroch, Eva Dolezelova, Lucie Rozkydalova, Tomas Smutny, Alejandro Carazo, Jaroslav Chladek, Martin Lenicek, Petr Nachtigal, Libor Vitek, Petr Pavek, Stanislav Micuda
Iron depletion (ID) has been shown to induce the liver expression of Cyp7a1, the rate-limiting enzyme initiating conversion of cholesterol to bile acids (BA), although the effect on bile acids metabolism and bile production is unknown. Therefore, we investigated changes in bile secretion and BA synthesis during diet-induced iron depletion (ID) in rats. ID increased bile flow along with augmented biliary excretion of bile acids, glutathione, cholesterol and phospholipids. Accordingly, we found transcriptional upregulation of the Cyp7a1, Cyp8b1, and Cyp27a1 BA synthetic enzymes, as well as induction of the Abcg5/8 cholesterol transporters in ID rat livers...
December 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28887089/steviol-an-aglycone-of-steviol-glycoside-sweeteners-interacts-with-the-pregnane-x-pxr-and-aryl-hydrocarbon-ahr-receptors-in-detoxification-regulation
#18
Jan Dusek, Alejandro Carazo, Frantisek Trejtnar, Lucie Hyrsova, Ondřej Holas, Tomas Smutny, Stanislav Micuda, Petr Pavek
Stevia rebaudiana Bertoni is a herb known for the high content of natural sweeteners in its leaves. Its main secondary metabolite stevioside is used as non-caloric sweetener. No information, however, is available on whether stevioside or steviol interact with drug-metabolizing enzymes and pose the potential risk of food-drug interactions. Similarly, data are lacking on the interactions of steviol and stevioside with key nuclear receptors controlling the expression of the main drug metabolizing enzymes. We studied the interactions of steviol and stevioside with the pregnane X (PXR), vitamin D (VDR), constitutive androstane (CAR), farnesoid X (FXR), glucocorticoid (GR) and aryl hydrocarbon (AHR) receptors, which control expression of genes of xenobiotic metabolism...
September 5, 2017: Food and Chemical Toxicology
https://www.readbyqxmd.com/read/28830343/divergence-of-functional-effects-among-bacterial-srna-paralogs
#19
I-Chen Kimberly Chen, Gregory J Velicer, Yuen-Tsu Nicco Yu
BACKGROUND: Non-coding small RNAs (sRNAs) regulate a variety of important biological processes across all life domains, including bacteria. However, little is known about the functional evolution of sRNAs in bacteria, which might occur via changes in sRNA structure and/or stability or changes in interactions between sRNAs and their associated regulatory networks, including target mRNAs. The sRNA Pxr functions as a developmental gatekeeper in the model cooperative bacterium Myxococcus xanthus...
August 22, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28825834/combining-genomics-to-identify-the-pathways-of-post-transcriptional-nongenotoxic-signaling-and-energy-homeostasis-in-livers-of-rats-treated-with-the-pregnane-x-receptor-agonist-pregnenolone-carbonitrile
#20
Hirohisa Nagahori, Kenji Nakamura, Kayo Sumida, Shingo Ito, Sumio Ohtsuki
Transcriptomic, proteomic, phosphoproteomic, and metabolomic analyses were combined to determine the role of pregnane X receptor (PXR) in nongenotoxic signaling and energy homeostasis in liver after rats were repeatedly orally dosed with the PXR agonist pregnenolone carbonitrile (PCN) for 7 days. Analyses of mRNAs and proteins in the supernatant, membrane, and cytosolic fractions of enlarged liver homogenates showed diverse expression profiles. Gene set enrichment analysis showed that the synchronous increase in mRNAs and proteins involved in chemical carcinogenesis and the response to drug was possibly mediated by the PXR pathway and proteasome core complex assembly was possibly mediated by the Nrf2 pathway...
September 6, 2017: Journal of Proteome Research
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