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https://www.readbyqxmd.com/read/28446029/sugar-free-pregnane-type-steroids-from-the-roots-of-cynanchum-stauntonii
#1
An-Jun Deng, Dan Zhang, Qian Li, Zhi-Hui Zhang, Zhi-Hong Li, Hai-Lin Qin
Two new sugar-free 14,15-secopregnane-type steroids, 14-O-methyl-3-epi-hirundigenin (1) and 2-deoxyamplexicogenin A (2), along with two known sugar-free pregnane-type steroids, were isolated from the 95% ethanol extract of the roots of Cynanchum stauntonii. The structures of the new compounds were characterized on the basis of extensive spectroscopic analyses, mainly 1D and 2D NMR methods, albeit the MS experiments did not display the molecular ion peaks. Compound 2 was the aglycones of stauntosides J and K, etc...
April 27, 2017: Journal of Asian Natural Products Research
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
#2
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 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. 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...
April 25, 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/28436464/glucose-dependent-regulation-of-pregnane-x-receptor-is-modulated-by-amp-activated-protein-kinase
#3
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
https://www.readbyqxmd.com/read/28432535/exploring-the-carbamazepine-interaction-with-human-pregnane-x-receptor-and-effect-on-abcc2-using-in-vitro-and-in-silico-approach
#4
Gurpreet K Grewal, Khuraijam D Singh, Neha Kanojia, Chitra Rawat, Samiksha Kukal, Ajay Jajodia, Anshika Singhal, Richa Misra, Selvaraman Nagamani, Karthikeyan Muthusamy, Ritushree Kukreti
PURPOSE: Over expression of ATP-binding cassette transporters is considered one of the major reasons for non-responsiveness to antiepileptic drugs. Carbamazepine (CBZ), one of first line antiepileptic drug is known to influence ABCC2 expression but its exact molecular mechanism is unknown. METHODS: We investigated the effect of CBZ on expression of ABCC2 and pregnane X receptor (PXR) in HepG2 cell line and compared with hyperforin (agonist of PXR) and ketoconazole (antagonist of PXR) through realtime PCR and western blot assay...
April 21, 2017: Pharmaceutical Research
https://www.readbyqxmd.com/read/28430654/alpha-ketoglutarate-suppresses-the-nf-%C3%AE%C2%BAb-mediated-inflammatory-pathway-and-enhances-the-pxr-regulated-detoxification-pathway
#5
Liuqin He, Huan Li, Niu Huang, Xihong Zhou, Junquan Tian, Tiejun Li, Jing Wu, Yanan Tian, Yulong Yin, Kang Yao
Alpha-ketoglutarate (AKG) is a critical nutritional factor in the maintenance of intestinal homeostasis. However, the relative mechanism of AKG has not been well understood. It was recently shown that the interaction between nuclear factor kappa B (NF-κB)-mediated inflammatory pathway and pregnane X receptor (PXR)-regulated detoxification pathway is a check and balance mechanism for keeping the homeostatic state of the intestine, preventing the onset of intestinal inflammation which may lead to cancer. In the current study we used lipopolysaccharide (LPS)-challenged piglet and intestinal porcine epithelial cells-J2 models to investigate the effects of dietary AKG supplementation on the intestinal immune system and PXR regulated target expression...
April 6, 2017: Oncotarget
https://www.readbyqxmd.com/read/28428226/rapid-throughput-analysis-of-gabaa-receptor-subtype-modulators-and-blockers-using-disbac1-3-membrane-potential-red-dye
#6
Atefeh Mousavi Nik, Brandon Pressly, Vikrant Singh, Shane Antrobus, Susan Hulsizer, Michael A Rogawski, Heike Wulff, Isaac N Pessah
Fluorometric Imaging Plate Reader (FLIPR®) membrane potential dye (FMP-Red-Dye) is a proprietary tool for basic discovery and high throughput drug screening for G-protein coupled receptors and ion channels. We optimized and validated this potentiometric probe to assay functional modulators of heterologous expressed GABAA receptor (GABAAR) isoforms (synaptic α1β3γ2, extrasynaptic α4β3δ, and β3 homopentomers). High-resolution mass spectrometry identified FMP-Red-dye as DisSBAC1(3). GABAAR expressing cells equilibrated with FMP-Red-Dye exhibited depolarized equilibrium membrane (Em) potentials compared to GABAAR-null cells...
April 20, 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/28428138/pregnane-x-receptor-regulates-the-ahr-cyp1a1-pathway-and-protects-liver-cells-from-benzo-%C3%AE-pyrene-induced-dna-damage
#7
Hongmei Cui, Xinsheng Gu, Jingshu Chen, Ying Xie, Sui Ke, Jing Wu, Andrei Golovko, Benjamin Morpurgo, Chunhong Yan, Timothy D Phillips, Wen Xie, Jianyuan Luo, Zhijun Zhou, Yanan Tian
Pregnane X receptor (PXR) plays an important role in protecting cells from mutagenic DNA damages induced by endogenous and exogenous toxicants. This protective function is often attributed to the PXR-regulated metabolic detoxification. Here we report a novel potential mechanism that PXR reduces benzo-[α]-pyrene(BaP)-induced DNA damage through inhibiting the transcriptional activity of aryl hydrocarbon receptor (AhR) which plays a pivotal role in the bioactivation of BaP. We have utilized three well-characterized cell lines, i...
April 17, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28420184/metajapogenins-a-c-pregnane-steroids-from-shells-of-metaplexis-japonica
#8
Hui-Li Yao, Yang Liu, Xiao-Hong Liu, Hua Gao, Kun Liu, Yan-Lin Shao, Xin-Yu Fang, Wei Wang
Phytochemical investigation of the shells of Metaplexis japonica (Thunb.) Makino, belonging to the family of Apocynaceae, afforded three new pregnane steroids, metajapogenins A-C, along with three known compounds. The structures of the new compounds were elucidated as 12β,14β,17β-trihydroxypregna-3,5-dien-7,20-dione, 12β,14β,17β,20β-tetrahydroxypregna-3,5-dien-7-one; 3β,12β,14β,17β-tetrahydroxypregn-5-ene-7,20-dione on the basis of extensive spectroscopic evidence derived from 1D; 2D-NMR experiments and mass spectrometry...
April 17, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28414139/ligand-dependent-and-independent-regulation-of-human-hepatic-sphingomyelin-phosphodiesterase-acid-like-3a-expression-by-pregnane-x-receptor-and-crosstalk-with-liver-x-receptor
#9
Judith Jeske, Andreas Bitter, Wolfgang E Thasler, Thomas S Weiss, Matthias Schwab, Oliver Burk
Pregnane X receptor (PXR) mainly regulates xenobiotic metabolism and detoxification. Additionally, it exerts pleiotropic effects on liver physiology, which in large parts depend on transrepression of other liver-enriched transcription factors. Based on the hypothesis that lower expression levels of PXR may reduce the extent of this inhibition, an exploratory genome-wide transcriptomic profiling was performed using HepG2 cell clones with different expression levels of PXR. This screen and confirmatory real-time RT-PCR identified sphingomyelin phosphodiesterase acid-like (SMPDL) 3A, a novel nucleotide phosphodiesterase and phosphoramidase, as being up-regulated by PXR-deficiency...
April 13, 2017: Biochemical Pharmacology
https://www.readbyqxmd.com/read/28408657/negative-regulation-of-human-pregnane-x-receptor-by-microrna-18a-5p-evidence-for-suppression-of-microrna-18a-5p-expression-by-rifampin-and-rilpivirine
#10
Devinder Sharma, Abdullah A Turkistani, Wenjun Chang, Catherine Hu, Zhaoming Xu, Thomas K H Chang
Small non-coding microRNAs act as post-transcriptional regulators of gene expression involved in diverse biological functions. Pregnane X receptor (PXR, NR1I2), which is a member of the superfamily of nuclear receptors, is a transcription factor governing the transport and biotransformation of various endobiotics and xenobiotics. In the present study, we identified a specific microRNA involved in regulating the expression and functionality of human PXR (hPXR). According to bioinformatics analysis employing three commonly used algorithms (TargetScan, miRanda, and DIANA-microT-CDS), miR-18a-5p was predicted to be the top candidate microRNA regulator of hPXR...
April 13, 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/28390928/itraconazole-cis-diastereoisomers-activate-aryl-hydrocarbon-receptor-ahr-and-pregnane-x-receptor-pxr-and-induce-cyp1a1-in-human-cell-lines-and-human-hepatocytes
#11
Martina Stepankova, Barbora Pastorkova, Petr Bachleda, Zdenek Dvorak
Triazole antimycotic itraconazole contains in its structure three chiral centres; therefore, it forms eight stereoisomers. Commercial preparations of itraconazole are a mixture of four cis-diastereoisomers. There is much evidence that efficacy, adverse effects, and toxicity of chiral drugs may be stereospecific. Therefore, we have prepared 4 pure cis-diastereoisomers of itraconazole and investigated their effects on transcriptional activities of xenoreceptors aryl hydrocarbon receptor AhR and pregnane X receptor PXR...
April 5, 2017: Toxicology
https://www.readbyqxmd.com/read/28361559/a-new-immunosuppressive-pregnane-glycoside-from-aqueous-fraction-of-epigynum-cochinchinensis
#12
Zong Wan, Yuan-Cheng Yao, Fei Gao, Sheng-Bao Cai, Afsar Khan, Tian-Rui Zhao, Xiao-Yan Yang, Jian Fan, Sheng-Yan Qian, Jian-Xin Cao, Gui-Guang Cheng
Chemical investigation on the aqueous fraction of the stems of Epigynum cochinchinensis led to the isolation of a new pregnane glycoside named as epigycoside A (1) along with three known analogues (2-4). The structure of compound 1 was elucidated by means of spectroscopic techniques, including HRESIMS, and 1D and 2D NMR experiments. The immunosuppressive activity of 1 was evaluated by an in vitro model of concanavalin A-induced mice splenocytes proliferation. Compound 1 showed significant inhibitory activity in a dose-dependent manner, closer to the efficacy of positive control, dexamethasone, at a concentration of 50 μM...
March 31, 2017: Natural Product Research
https://www.readbyqxmd.com/read/28356150/pregnane-x-receptor-is-associated-with-unfavorable-survival-and-induces-chemotherapeutic-resistance-by-transcriptional-activating-multidrug-resistance-related-protein-3-in-colorectal-cancer
#13
Yan Dong, Zhe Wang, Gan-Feng Xie, Chong Li, Wen-Wei Zuo, Gang Meng, Cheng-Ping Xu, Jian-Jun Li
BACKGROUND: Although chemotherapy represents a predominant anti-cancer therapeutic modality, drug treatment efficacy is often limited due to the development of resistant tumor cells. The pregnane X receptor (PXR) affects chemotherapeutic effects by regulating targets involved in drug metabolism and transportation, but the regulatory mechanism is poorly understood. METHODS: Oxaliplatin (L-OHP) content in tumor cells was analyzed by mass cytometry. The roles of PXR on cancer cell proliferation, apoptosis and tumor growth with L-OHP-treated were investigated by MTS, colony formation, flow cytometry and xenograft tumor assays...
March 29, 2017: Molecular Cancer
https://www.readbyqxmd.com/read/28335376/genetic-polymorphisms-contribute-to-the-individual-variations-of-imatinib-mesylate-plasma-levels-and-adverse-reactions-in-chinese-gist-patients
#14
Jing Liu, Zhiyu Chen, Hanmei Chen, Yingyong Hou, Weiqi Lu, Junyi He, Hanxing Tong, Yuhong Zhou, Weimin Cai
Imatinib mesylate (IM) has dramatically improved the outcomes of gastrointestinal stromal tumor (GIST) patients. However, the clinical responses of IM may considerably vary among single individuals. This study aimed to investigate the influences of genetic polymorphisms of drug-metabolizing enzyme (CYP3A4), transporters (ABCB1, ABCG2), and nuclear receptor (Pregnane X Receptor (PXR, encoded by NR1I2)) on IM plasma levels and related adverse reactions in Chinese GIST patients. A total of 68 Chinese GIST patients who have received IM 300-600 mg/day were genotyped for six single nucleotide polymorphisms (SNPs) (CYP3A4 rs2242480; ABCB1 rs1045642; ABCG2 rs2231137; NRI12 rs3814055, rs6785049, rs2276706), and the steady-state IM trough plasma concentrations were measured by a validated HPLC method...
March 13, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28327628/corrigendum-pregnane-x-receptor-regulates-pathogen-induced-inflammation-and-host-defense-against-an-intracellular-bacterial-infection-through-toll-like-receptor-4
#15
Zhijuan Qiu, Jorge L Cervantes, Basak B Cicek, Subhajit Mukherjee, Madhukumar Venkatesh, Leigh A Maher, Juan C Salazar, Sridhar Mani, Kamal M Khanna
No abstract text is available yet for this article.
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28320072/constitutive-androstane-receptor-regulates-the-intestinal-mucosal-response-to-injury
#16
Grace M Hudson, Kyle L Flannigan, Sarah L Erickson, Fernando A Vicentini, Alexandra Zamponi, Christina L Hirota, Laurie Alston, Christophe Altier, Subrata Ghosh, Kevin P Rioux, Sridhar Mani, Thomas K Chang, Simon A Hirota
BACKGROUND AND PURPOSE: The pathogenesis of the inflammatory bowel diseases (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), involves aberrant interactions between a genetically susceptible individual, their microbiota and environmental factors. Alterations in xenobiotic receptor expression and function are associated with increased risk for IBD. Here, we have assessed the role of the constitutive androstane receptor (CAR), a xenobiotic receptor closely related to the pregnane X receptor, in the regulation of intestinal mucosal homeostasis...
March 20, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28318987/a-clinical-evaluation-of-the-pharmacokinetics-and-pharmacodynamics-of-intravenous-alfaxalone-in-cyclodextrin-in-male-and-female-rats-following-a-loading-dose-and-constant-rate-infusion
#17
Kate L White, Stuart Paine, John Harris
OBJECTIVE: To characterise, as a clinical study, the pharmacokinetics and pharmacodynamics and describe the hypnotic effect of the neurosteroid alfaxalone (3α-hydroxy-5 α-pregnane-11, 20-dione) formulated with 2-hydroxypropyl-β-cyclodextrin in male and female rats. STUDY DESIGN: Prospective, experimental laboratory study. ANIMALS: A total of 12 (six male and six female) adult, aged-matched Sprague Dawley rats. METHODS: Surgery and instrumentation was performed under isoflurane anaesthesia in an oxygen/nitrous oxide mixture (1:2) and local anaesthetic infiltration...
February 1, 2017: Veterinary Anaesthesia and Analgesia
https://www.readbyqxmd.com/read/28315689/in-silico-prediction-of-hpxr-activators-using-structure-based-pharmacophore-modeling
#18
Nao Torimoto-Katori, Ruili Huang, Harutoshi Kato, Rikiya Ohashi, Menghang Xia
The activation of pregnane X receptor (PXR), a member of the nuclear receptor superfamily, can mediate potential drug-drug interactions by regulating the expression of several drug- mediated enzymes and transporters, resulting in reduced therapeutic efficacy or increased toxicity by producing reactive metabolites. Therefore, in the early stage of drug development, it is important to predict these risks using an in silico approach. We constructed a human PXR (hPXR) pharmacophore model based on known structural information of compounds that activate PXR...
March 15, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28303499/pregnane-x-receptor-not-nuclear-factor-kappa-b-up-regulates-p-glycoprotein-expression-in-the-brain-of-chronic-epileptic-rats-induced-by-kainic-acid
#19
Nian Yu, Yan-Fang Zhang, Kang Zhang, Yong-Fei Cheng, Hai-Yan Ma, Qing Di
Drug-resistance epilepsy (DRE) is attributed to the brain P-glycoprotein (P-gp) overexpression. We previously reported that nuclear factor-kappa B (NF-κB) played a critical role in regulating P-gp expression at the brain of the acute seizure rats. This study was extended further to investigate the interaction effect of NF-κB and pregnane X receptor (PXR) on P-gp expression at the brain of chronic epileptic rats treated with carbamazepine (CBZ). The chronic epileptic models were induced by the micro-injection of kainic acid (KA) into rats' hippocampus...
March 16, 2017: Neurochemical Research
https://www.readbyqxmd.com/read/28300701/novel-immunosuppressive-pregnane-glycosides-from-the-leaves-of-epigynum-auritum
#20
Fei Gao, Yuan-Cheng Yao, Sheng-Bao Cai, Tian-Rui Zhao, Xiao-Yan Yang, Jian Fan, Xiao-Nian Li, Jian-Xin Cao, Gui-Guang Cheng
Phytochemical investigation on the leaves of Epigynum auritum led to the isolation of three novel C21 pregnane glycosides, epigynosides, E-G (1-3), together with two known pregnane glycosides, epigynosides A (4) and C (5). Their structures were elucidated based on extensive spectroscopic data (MS, IR, 1D and 2D NMR) analysis, as well as comparison with the reported data. The immunological activities of the new compounds was evaluated against concanavalin A (Con A)-stimulated proliferation of mice splenocyte in vitro...
April 2017: Fitoterapia
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