Pregnane X Receptor (PXR; NR1I2)
This assay product utilizes proprietary human cells engineered to provide constitutive, high-level expression of the Human Pregnane X Receptor (NR1I2), a ligand-dependent transcription factor commonly referred to as PXR. PXR is also known as the Steroid and Xenobiotic sensing nuclear receptor (SXR).
INDIGO’s Reporter Cells express a hybrid form of human PXR. The N-terminal sequence encoding the PXR DNA binding domain (DBD) has been substituted with that of the yeast GAL4-DBD. The native PXR ligand binding domain (LBD) and other C-terminal domains remain intact and functional. Ligand interaction activates the receptor, causing it to binds to the GAL4 DNA binding sequence, which is functionally linked to a resident luciferase reporter gene. Thus, quantifying changes in luciferase activity in the treated reporter cells provides a sensitive surrogate measure of the changes in PXR activity. The principle application of this reporter assay system is in the screening of test samples to quantify any functional activity, either agonist or antagonist, that they may exert against human PXR.
Pregnane X Receptor is a nuclear receptor that binds and is activated by variety of endogenous and xenobiotic compounds. Activated by the antibiotic rifampicin and various plant metabolites, such as hyperforin, guggulipid, colupulone, and isoflavones, PXR's response to specific ligands is species-specific. It is activated by naturally occurring steroids, such as pregnenolone and progesterone, and binds to a response element in the promoters of the CYP3A4 and ABCB1/MDR1 genes.
For more information on PXR, visit the Nuclear Receptor Resource.
Kits are offered in different assay formats to accommodate researchers’ needs: 3x 32, 1x 96, and 1x 384 assay formats for screening small numbers of test compounds, as well as custom bulk reagents for HTS applications. Assay systems are all inclusive, providing reporter cells, optimized growth media, media for diluting test compounds, a positive-control agonist, luciferase detection reagent, a white assay plate, a detailed protocol, and a protocol quick guide. All kits are shipped on dry ice.
PXR Reporter Cells are prepared using INDIGO’s proprietary CryoMite™ process. This cryo-preservation method yields exceptional cell viability post-thaw, and provides the convenience of immediately dispensing healthy, division-competent reporter cells into assay plates. There is no need for cumbersome intermediate treatment steps such as spin-and-rinse of cells, viability determinations, or cell titer adjustments prior to assay setup.
INDIGO Bioscience’s Nuclear Receptor Reporter Assays are all-inclusive cell-based assay systems. In addition to PXR Reporter Cells, this kit provides two optimized media for use during cell culture and in diluting the user’s test samples, a reference agonist, Luciferase Detection Reagent, and a cell culture-ready assay plate. PXR Reporter Cells cannot be refrozen or maintained in extended culture.
|Product Family||Product Number||Product Description|
|IB0700 PXR (NR1I2)||IB07001-32||Human PXR Reporter Assay System, 3 x 32 assays in 96-well format|
|IB07001||Human PXR Reporter Assay System, 1 x 96-well format assays|
|IB07002||Human PXR Reporter Assay System, 1 x 384-well format assays|
Service Assays: Human, Rat, Mouse, Cynomolgus Monkey, Dog
The primary application of INDIGO’s cell-based nuclear receptor assays are to quantitatively assess the bioactivity of a test compound as an agonist (activator) or antagonist (inhibition of an agonist response) of a given receptor. Service assays include a positive control reference compound and “vehicle” control for every experiment. A formal study report and all data files are provided to the client upon completion of the study. To receive a quote for your proposed study, complete & submit the online “Request a Quote” form or contact an INDIGO Customer Service Representative to discuss your desired study parameters. To initiate a Service Study, download and complete all fields of the Excel worksheet “Service Work Order" then submit the electronic file to INDIGO Customer Service.
Sedaxane—Use of Nuclear Receptor Transactivation Assays, Toxicogenomics, and Toxicokinetics as Part of a Mode of Action Framework for Rodent Liver Tumors
ABSTRACT Experimental data demonstrate a mode of action (MOA) for liver tumors in male rats and mice treated with sedaxane that starts with activation of CAR, followed by altered expression of CAR-responsive genes, increased cell proliferation, and eventually clonal expansion of preneoplastic cells, leading to the development of altered foci and tumors. This MOA is
View Full Size Research conducted by: Koji Toyokawa (1), Ewa Maddox (1), Jack Vanden Huevel (1,2), & Bruce Sherf (1) (1) INDIGO Biosciences, Inc., 1981 Pine Hall Rd, State College, PA, USA (2) Center for Molecular Toxicology and Carcinogenesis, 325 Life Sciences Building, Penn State University, University Park, PA 16802, USA Date of Publication: 2017
Mouse Liver Tumor Mode of Action: Use of Toxicogenomics in Weight of Evidence for Human Relevance Assessment
ABSTRACT The Use of Toxicogenomics in Chemical Safety Testing Current safety testing is geared to produce and accept descriptive data from high-dose animal studies Interpretation of this information has effectively protected our health and safety for decates; however, hindered by lack of understanding mechanistic information Concern over chemical safety for humans and the environment has
Species Differences in Pregnane X Receptor Activation: Examination of common laboratory animal species
ABSTRACT Nuclear receptors (NRs) are ligand-dependent transcription factors found in many species that regulate the expression of important target genes involved in a spectrum of developmental and physiological processes. The ligand binding domain (LBD) of NRs is responsible for both ligand recognition and regulation of protein-protein interactions, notably with coregulatory factors. NRs represent important targets
Expansion of Assay Critical to the Study of Metabolism and Drug-Drug Interactions State College, PA (June 7, 2016) INDIGO Biosciences, a recognized industry-leading provider of nuclear receptor products and services, announced today that it has completed development of the next generation of Pregnane X Receptor (PXR) technology. Previously available in kits and services for only
In vitro toxicology platform provides predictive model of liver toxicity. Aims to reduce the high rates of drug-induced liver damage State College, PA (May 4, 2016) INDIGO Biosciences, the recognized industry leader in nuclear receptor research, has completed development of an in vitro toxicology platform, meeting the demand for predictive liver toxicity models. INDIGO’s in
INDIGO Biosciences, a recognized industry leading provider of nuclear receptor products and services, announced today that it has completed development and licensing of Pregnane X Receptor (PXR) technology. Kits and services are available for immediate purchase in both Human and Rat PXR. PXR regulates genes critically involved in metabolism. It plays an important role in
ABSTRACT The bacteriostat triclosan (2,4,4′-trichloro-2′-hydroxydiphenylether) (TCS) decreases rat serum thyroxine via putative nuclear receptor (NR) interaction(s) and subsequent transcriptional up-regulation of hepatic catabolism and clearance. However, due to the evolutionary divergence of the constitutive androstane and pregnane-X receptors (CAR, PXR), TCS-mediated downstream effects may be species-dependent. To test the hypothesis that TCS activates xenobiotic NRs