Identification of Modulators That Activate the Constitutive Androstane Receptor From the Tox21 10K Compound Library

Lynch, Caitlin; Mackowiak, Bryan; Huang, Ruili; Li, Linhao; Heyward, Scott; Sakamuru, Srilatha; Wang, Hongbing; Xia, Menghang

doi:10.1093/toxsci/kfy242

Cited by 32 publications

(33 citation statements)

References 50 publications

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“…However, this unique orphan NR has constitutive activity in immortalized cells, meaning CAR is found inside the nucleus and is already activated without a ligand present. This makes screening for modulators a difficult task, and requires the use of liver cells or a selective antagonist to reverse the constitutive activity [31]. Interestingly, CAR also regulates CYP3A4 to an extent, but majorly regulates CYP2B6, included in the CYP2B isoenzyme family responsible for approximately 25% of the metabolism of marketed drugs [32].…”

Section: Role Of Transcription Factors In Cyp450 Regulationmentioning

confidence: 99%

Application of In Vitro Metabolism Activation in High-Throughput Screening

Ooka

Lynch

Xia

2020

IJMS

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In vitro methods which incorporate metabolic capability into the assays allow us to assess the activity of metabolites from their parent compounds. These methods can be applied into high-throughput screening (HTS) platforms, thereby increasing the speed to identify compounds that become active via the metabolism process. HTS was originally used in the pharmaceutical industry and now is also used in academic settings to evaluate biological activity and/or toxicity of chemicals. Although most chemicals are metabolized in our body, many HTS assays lack the capability to determine compound activity via metabolism. To overcome this problem, several in vitro metabolic methods have been applied to an HTS format. In this review, we describe in vitro metabolism methods and their application in HTS assays, as well as discuss the future perspectives of HTS with metabolic activity. Each in vitro metabolism method has advantages and disadvantages. For instance, the S9 mix has a full set of liver metabolic enzymes, but it displays high cytotoxicity in cell-based assays. In vitro metabolism requires liver fractions or the use of other metabolically capable systems, including primary hepatocytes or recombinant enzymes. Several newly developed in vitro metabolic methods, including HepaRG cells, three-dimensional (3D) cell models, and organ-on-a-chip technology, will also be discussed. These newly developed in vitro metabolism approaches offer significant progress in dissecting biological processes, developing drugs, and making toxicology studies quicker and more efficient.

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Section: Role Of Transcription Factors In Cyp450 Regulationmentioning

confidence: 99%

Application of In Vitro Metabolism Activation in High-Throughput Screening

Ooka

Lynch

Xia

2020

IJMS

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“…Development of various in vitro assays, coupled with mutagenesis and structural models, have clearly established that diverse chemicals act either as direct agonists or inverse agonists of CAR [ 91 , 92 , 93 , 94 ]. However, some compounds including PB are called indirect activators due to their inability to elicit binding to CAR, as measured by e.g., recruitment of NR coactivators, despite the fact that these compounds can induce CAR target genes [ 95 ].…”

Section: Key Characteristics Of Car and Its Activation Processmentioning

confidence: 99%

“…A large repertoire of pharmaceuticals are CAR activators [ 72 , 94 ], while information on their effects on energy metabolism is largely unknown, and not further analyzed in this work. As one example, exposure to statins is a known risk factor for type 2 diabetes (e.g., [ 234 ]).…”

Section: Metabolic Effects Of Edc Classes Potentially Mediated By mentioning

confidence: 99%

Metabolism-Disrupting Chemicals and the Constitutive Androstane Receptor CAR

Küblbeck

Niskanen

Honkakoski

2020

Cells

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During the last two decades, the constitutive androstane receptor (CAR; NR1I3) has emerged as a master activator of drug- and xenobiotic-metabolizing enzymes and transporters that govern the clearance of both exogenous and endogenous small molecules. Recent studies indicate that CAR participates, together with other nuclear receptors (NRs) and transcription factors, in regulation of hepatic glucose and lipid metabolism, hepatocyte communication, proliferation and toxicity, and liver tumor development in rodents. Endocrine-disrupting chemicals (EDCs) constitute a wide range of persistent organic compounds that have been associated with aberrations of hormone-dependent physiological processes. Their adverse health effects include metabolic alterations such as diabetes, obesity, and fatty liver disease in animal models and humans exposed to EDCs. As numerous xenobiotics can activate CAR, its role in EDC-elicited adverse metabolic effects has gained much interest. Here, we review the key features and mechanisms of CAR as a xenobiotic-sensing receptor, species differences and selectivity of CAR ligands, contribution of CAR to regulation hepatic metabolism, and evidence for CAR-dependent EDC action therein.

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“…The Tox21 chemical library is composed of 9,667 substances and 8,305 unique structures excluding mixtures and ions. The Tox21 library was built from a federal cross-agency effort covering a large chemical space as discussed in 16,42,43 , and includes diverse chemical groups e.g. pesticides, antimicrobials, (2020) 10:3986 | https://doi.org/10.1038/s41598-020-60747-3 www.nature.com/scientificreports www.nature.com/scientificreports/ water contaminants, industrial chemicals, high production volume chemicals, endocrine disruptors, FDA food additives, fragrances, plasticizers and drugs.…”

Section: Tox21 Chemical Librarymentioning

confidence: 99%

High-Throughput Screening to Predict Chemical-Assay Interference

Borrel

Huang

Sakamuru

et al. 2020

Sci Rep

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The U.S. federal consortium on toxicology in the 21 st century (Tox21) produces quantitative, highthroughput screening (HTS) data on thousands of chemicals across a wide range of assays covering critical biological targets and cellular pathways. Many of these assays, and those used in other in vitro screening programs, rely on luciferase and fluorescence-based readouts that can be susceptible to signal interference by certain chemical structures resulting in false positive outcomes. Included in the Tox21 portfolio are assays specifically designed to measure interference in the form of luciferase inhibition and autofluorescence via multiple wavelengths (red, blue, and green) and under various conditions (cell-free and cell-based, two cell types). Out of 8,305 chemicals tested in the Tox21 interference assays, percent actives ranged from 0.5% (red autofluorescence) to 9.9% (luciferase inhibition). Self-organizing maps and hierarchical clustering were used to relate chemical structural clusters to interference activity profiles. Multiple machine learning algorithms were applied to predict assay interference based on molecular descriptors and chemical properties. the best performing predictive models (accuracies of ~80%) have been included in a web-based tool called InterPred that will allow users to predict the likelihood of assay interference for any new chemical structure and thus increase confidence in HTS data by decreasing false positive testing results. Chemical hazard assessment testing in the twenty-first century has evolved to encompass large high-throughput screening (HTS) research programs, designed to produce quantitative data on the activity of thousands of chemicals across hundreds of biological targets and pathways, a strategy that has long been used in drug discovery. Such efforts, exemplified by the federal Tox21 research consortium 1,2 , are intended to facilitate rapid chemical hazard screening, predictive computational toxicology using machine learning and artificial intelligence techniques, and human-relevant systems biology models that provide mechanistic insight into chemical toxicity (e.g. 3). The Tox21 program and other such HTS initiatives rely upon an array of biological assays, i.e. analytical measurement procedures defined by a set of reagents that produce a detectable signal, allowing a biological process to be quantified 4. Many HTS platforms use cell-based assays measuring processes such as cell growth/death, receptor binding, or protein expression while others are cell-free assays that characterize biochemical activity. Both formats use a variety of detection technologies including fluorescence and luminescence readouts. Fluorescence-based assays are one of the leading technologies in terms of widespread application reported in PubChem 5,6. Indeed, the routinely used fluorescence intensity-based format allows for optimization of speed, accuracy, reproducibility and sensitivity of assays 7. Luminescence is frequently used as a readout from luciferase-based reporter gene assays and pro...

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Identification of Modulators That Activate the Constitutive Androstane Receptor From the Tox21 10K Compound Library

Cited by 32 publications

References 50 publications

Application of In Vitro Metabolism Activation in High-Throughput Screening

Application of In Vitro Metabolism Activation in High-Throughput Screening

Metabolism-Disrupting Chemicals and the Constitutive Androstane Receptor CAR

High-Throughput Screening to Predict Chemical-Assay Interference

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