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Sanz-Serrano J, Callewaert E, De Boever S, Drees A, Verhoeven A, Vinken M. Chemical-induced liver cancer: an adverse outcome pathway perspective. Expert Opin Drug Saf 2024; 23:425-438. [PMID: 38430529 DOI: 10.1080/14740338.2024.2326479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 02/29/2024] [Indexed: 03/04/2024]
Abstract
INTRODUCTION The evaluation of the potential carcinogenicity is a key consideration in the risk assessment of chemicals. Predictive toxicology is currently switching toward non-animal approaches that rely on the mechanistic understanding of toxicity. AREAS COVERED Adverse outcome pathways (AOPs) present toxicological processes, including chemical-induced carcinogenicity, in a visual and comprehensive manner, which serve as the conceptual backbone for the development of non-animal approaches eligible for hazard identification. The current review provides an overview of the available AOPs leading to liver cancer and discusses their use in advanced testing of liver carcinogenic chemicals. Moreover, the challenges related to their use in risk assessment are outlined, including the exploitation of available data, the need for semantic ontologies, and the development of quantitative AOPs. EXPERT OPINION To exploit the potential of liver cancer AOPs in the field of risk assessment, 3 immediate prerequisites need to be fulfilled. These include developing human relevant AOPs for chemical-induced liver cancer, increasing the number of AOPs integrating quantitative toxicodynamic and toxicokinetic data, and developing a liver cancer AOP network. As AOPs and other areas in the field continue to evolve, liver cancer AOPs will progress into a reliable and robust tool serving future risk assessment and management.
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Affiliation(s)
- Julen Sanz-Serrano
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Ellen Callewaert
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Sybren De Boever
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Annika Drees
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Anouk Verhoeven
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Mathieu Vinken
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
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2
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Nolen RM, Prouse A, Russell ML, Bloodgood J, Díaz Clark C, Carmichael RH, Petersen LH, Kaiser K, Hala D, Quigg A. Evaluation of fatty acids and carnitine as biomarkers of PFOS exposure in biota (fish and dolphin) from Galveston Bay and the northwestern Gulf of Mexico. Comp Biochem Physiol C Toxicol Pharmacol 2024; 276:109817. [PMID: 38101762 DOI: 10.1016/j.cbpc.2023.109817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 11/10/2023] [Accepted: 12/07/2023] [Indexed: 12/17/2023]
Abstract
Perfluorooctane sulfonate (PFOS) is a ubiquitous pollutant that elicits a wide range of toxic effects in exposed biota. Coastal zones in highly urbanized or industrial areas are particularly vulnerable to PFOS pollution. At present, information is lacking on biomarkers to assess PFOS effects on aquatic wildlife. This study investigated the efficacy of l-carnitine (or carnitine) and fatty acids as biomarkers of PFOS exposure in aquatic biota. The levels of PFOS, total and free carnitine, and 24 fatty acids (measured as fatty acid methyl esters or FAMEs) were measured in the liver, and muscle or blubber, of fish and dolphins sampled from Galveston Bay and the northern Gulf of Mexico (nGoM). Overall, bottlenose dolphins (Tursiops truncatus) had the highest hepatic PFOS levels. Galveston Bay fish, gafftopsail catfish (Bagre marinus), red drum (Sciaenops ocellatus), and spotted seatrout (Cynoscion nebulosus), had hepatic PFOS levels ∼8-13× higher than nGoM pelagic fish species, red snapper (Lutjanus campechanus) and yellowfin tuna (Thunnus albacares). The multivariate analysis of PFOS liver body-burdens and biomarkers found carnitine to be a more modal biomarker of PFOS exposure than FAMEs. Significant positive correlation of hepatic PFOS levels with total carnitine was evident for biota from Galveston Bay (fish only), and a significant correlation between PFOS and total and free carnitine was evident for biota from the nGoM (fish and dolphins). Given the essential role of carnitine in mediating fatty acid β-oxidation, our results suggest carnitine to be a likely candidate biomarker of environmental PFOS exposure and indicative of potential dyslipidemia effects.
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Affiliation(s)
- Rayna M Nolen
- Department of Marine Biology, Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, TX 77553, USA.
| | - Alexandra Prouse
- Department of Marine Biology, Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, TX 77553, USA
| | - Mackenzie L Russell
- University Programs, Dauphin Island Sea Lab, 101 Bienville Blvd, Dauphin Island, AL 36528, USA
| | - Jennifer Bloodgood
- University Programs, Dauphin Island Sea Lab, 101 Bienville Blvd, Dauphin Island, AL 36528, USA; Stokes School of Marine and Environmental Sciences, University of South Alabama, 307 N University Blvd, Mobile, AL 36688, USA; Cornell Wildlife Health Lab, Cornell University College of Veterinary Medicine, 240 Farrier Rd, Ithaca, NY 14853, USA
| | - Cristina Díaz Clark
- University Programs, Dauphin Island Sea Lab, 101 Bienville Blvd, Dauphin Island, AL 36528, USA
| | - Ruth H Carmichael
- University Programs, Dauphin Island Sea Lab, 101 Bienville Blvd, Dauphin Island, AL 36528, USA; Stokes School of Marine and Environmental Sciences, University of South Alabama, 307 N University Blvd, Mobile, AL 36688, USA
| | - Lene H Petersen
- Department of Marine Biology, Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, TX 77553, USA
| | - Karl Kaiser
- Department of Marine and Coastal Environmental Science, Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, TX 77553, USA; Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77843, USA
| | - David Hala
- Department of Marine Biology, Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, TX 77553, USA
| | - Antonietta Quigg
- Department of Marine Biology, Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, TX 77553, USA; Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX 77843, USA; Department of Ecology and Conservation Biology, Texas A&M University, 3146 TAMU, College Station, TX 77843, USA
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3
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Robarts DR, Dai J, Lau C, Apte U, Corton JC. Hepatic Transcriptome Comparative In Silico Analysis Reveals Similar Pathways and Targets Altered by Legacy and Alternative Per- and Polyfluoroalkyl Substances in Mice. TOXICS 2023; 11:963. [PMID: 38133364 PMCID: PMC10748317 DOI: 10.3390/toxics11120963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/20/2023] [Accepted: 11/25/2023] [Indexed: 12/23/2023]
Abstract
Per- and poly-fluoroalkyl substances (PFAS) are a large class of fluorinated carbon chains that include legacy PFAS, such as perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS). These compounds induce adverse health effects, including hepatotoxicity. Potential alternatives to the legacy PFAS (HFPO-DA (GenX), HFPO4, HFPO-TA, F-53B, 6:2 FTSA, and 6:2 FTCA), as well as a byproduct of PFAS manufacturing (Nafion BP2), are increasingly being found in the environment. The potential hazards of these new alternatives are less well known. To better understand the diversity of molecular targets of the PFAS, we performed a comparative toxicogenomics analysis of the gene expression changes in the livers of mice exposed to these PFAS, and compared these to five activators of PPARα, a common target of many PFAS. Using hierarchical clustering, pathway analysis, and predictive biomarkers, we found that most of the alternative PFAS modulate molecular targets that overlap with legacy PFAS. Only three of the 11 PFAS tested did not appreciably activate PPARα (Nafion BP2, 6:2 FTSA, and 6:2 FTCA). Predictive biomarkers showed that most PFAS (PFHxS, PFOA, PFOS, PFNA, HFPO-TA, F-53B, HFPO4, Nafion BP2) activated CAR. PFNA, PFHxS, PFOA, PFOS, HFPO4, HFPO-TA, F-53B, Nafion BP2, and 6:2 FTSA suppressed STAT5b, activated NRF2, and activated SREBP. There was no apparent relationship between the length of the carbon chain, type of head group, or number of ether linkages and the transcriptomic changes. This work highlights the similarities in molecular targets between the legacy and alternative PFAS.
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Affiliation(s)
- Dakota R. Robarts
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jiayin Dai
- State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants, School of Environmental Sciences and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Christopher Lau
- Center for Public Health and Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Udayan Apte
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - J. Christopher Corton
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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4
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Solan ME, Lavado R. Effects of short-chain per- and polyfluoroalkyl substances (PFAS) on human cytochrome P450 (CYP450) enzymes and human hepatocytes: An in vitro study. Curr Res Toxicol 2023; 5:100116. [PMID: 37575337 PMCID: PMC10412865 DOI: 10.1016/j.crtox.2023.100116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/14/2023] [Accepted: 07/18/2023] [Indexed: 08/15/2023] Open
Abstract
Short-chain per- and polyfluoroalkyl substances (PFAS) have been developed as alternatives to legacy long-chain PFAS, but they may still pose risks due to their potential to interact with biomolecules. Cytochrome P450 (CYP450) enzymes are essential for xenobiotic metabolism, and disruptions of these enzymes by PFAS can have significant human health implications. The inhibitory potential of two legacy long-chain (PFOA and PFOS) and five short-chain alternative PFAS (PFBS, PFHxA, HFPO-DA, PFHxS, and 6:2 FTOH) were assessed in recombinant CYP1A2, - 2B6, -2C19, -2E1, and -3A4 enzymes. Most of the short-chain PFAS, except for PFHxS, tested did not result in significant inhibition up to 100 μM. PFOS inhibited recombinant CYP1A2, -2B6, -2C19, and -3A4 enzymes. However, concentrations where inhibition occurred, were all higher than the averages reported in population biomonitoring studies, with IC50 values higher than 10 µM. We also evaluated the activities of CYP1A2 and CYP3A4 in HepaRG monolayers following 48 h exposures of the short-chain PFAS at two concentrations (1 nM or 1 µM) and with or without an inducer (benzo[a]pyrene, BaP, for CYP1A2 and rifampicin for CYP3A4). Our findings suggest that both 1 nM and 1 µM exposures to short-chain PFAS can modulate the CYP1A2 activity induced by BaP. Except for PFHxS, the short-chain PFAS appear to have little effect on CYP3A4 activity. Understanding the effects of PFAS exposure on biotransformation can shed light on the mechanisms of PFAS toxicity and aid in developing effective strategies for managing chemical risks, enabling regulators to make more informed decisions.
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Affiliation(s)
- Megan E. Solan
- Department of Environmental Science, Baylor University, Waco, TX 76798, United States
| | - Ramon Lavado
- Department of Environmental Science, Baylor University, Waco, TX 76798, United States
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Bitencourt de Morais Valentim JM, Fagundes TR, Okamoto Ferreira M, Lonardoni Micheletti P, Broto Oliveira GE, Cremer Souza M, Geovana Leite Vacario B, da Silva JC, Scandolara TB, Gaboardi SC, Zanetti Pessoa Candiotto L, Mara Serpeloni J, Rodrigues Ferreira Seiva F, Panis C. Monitoring residues of pesticides in food in Brazil: A multiscale analysis of the main contaminants, dietary cancer risk estimative and mechanisms associated. Front Public Health 2023; 11:1130893. [PMID: 36908412 PMCID: PMC9992878 DOI: 10.3389/fpubh.2023.1130893] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 01/27/2023] [Indexed: 02/24/2023] Open
Abstract
Introduction Pesticides pose a risk for cancer development and progression. People are continuously exposed to such substances by several routes, including daily intake of contaminated food and water, especially in countries that are highly pesticide consumers and have very permissive legislation about pesticide contamination as Brazil. This work investigated the relationship among pesticides, food contamination, and dietary cancer risk. Methods Analyzed two social reports from the Brazilian Government: the Program for Analysis of Residues of Pesticides in Food (PARA) and The National Program for Control of Waste and Contaminants (PNCRC). Results and discussion First, we characterized the main pesticide residues detected over the maximum limits allowed by legislation or those prohibited for use in food samples analyzed across the country. Based on this list, we estimated the dietary cancer risks for some of the selected pesticides. Finally, we searched for data about dietary cancer risks and carcinogenic mechanisms of each pesticide. We also provided a critical analysis concerning the pesticide scenario in Brazil, aiming to discuss the food contamination levels observed from a geographical, political, and public health perspective. Exposures to pesticides in Brazil violate a range of human rights when food and water for human consumption are contaminated.
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Affiliation(s)
| | - Tatiane Renata Fagundes
- Department of Biological Sciences, Universidade Estadual do Norte do Paraná (UENP), Jacarezinho, Brazil
| | - Mariane Okamoto Ferreira
- Center of Health Sciences, Universidade Estadual do Oeste do Paraná (UNIOESTE), Blumenau, Brazil
| | | | | | - Milena Cremer Souza
- Department of Pathological Sciences, Universidade Estadual de Londrina (UEL), Londrina, Brazil
| | | | | | | | - Shaiane Carla Gaboardi
- Center of Health Sciences, Universidade Estadual do Oeste do Paraná (UNIOESTE), Blumenau, Brazil
- Instituto Federal Catarinense, Blumenau, Brazil
| | | | - Juliana Mara Serpeloni
- Department of Pathological Sciences, Universidade Estadual de Londrina (UEL), Londrina, Brazil
| | - Fábio Rodrigues Ferreira Seiva
- Department of Pathological Sciences, Universidade Estadual de Londrina (UEL), Londrina, Brazil
- Department of Biological Sciences, Universidade Estadual do Norte do Paraná (UENP), Jacarezinho, Brazil
| | - Carolina Panis
- Department of Pathological Sciences, Universidade Estadual de Londrina (UEL), Londrina, Brazil
- Center of Health Sciences, Universidade Estadual do Oeste do Paraná (UNIOESTE), Blumenau, Brazil
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6
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Taylor R, Armstrong L, Bhattacharya A, Henry Z, Brinker A, Buckley B, Kong B, Guo G. Myclobutanil-mediated alteration of liver-gut FXR signaling in mice. Toxicol Sci 2023; 191:387-399. [PMID: 36511616 PMCID: PMC9936201 DOI: 10.1093/toxsci/kfac129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The effects of exposure to Myclobutanil, a triazole fungicide, on the development and progression of nonalcoholic fatty liver disease (NAFLD) are unclear, but activation of nuclear receptors (NRs) is a known mechanism of azole-induced liver toxicity. Farnesoid X receptor (FXR) is a NR and is highly expressed in the liver and intestine. Activation of FXR tightly regulates bile acid (BA), lipid and glucose homeostasis, and inflammation partly through the induction of fibroblast growth factor 15 (FGF15; human ortholog FGF19). FXR activation is downregulated during NAFLD and agonists are currently being explored as potential therapeutic strategy. In this study, we aimed to clarify the effects of Myclobutanil exposure on FXR activation and NAFLD development. Reporter assay showed Myclobutanil treatment, following FXR activation with potent FXR agonist (GW4064), resulted in a dose-dependent decrease of FXR activity. Furthermore, a 10-day study in male mice demonstrated that cotreatment with Myclobutanil led to an 80% reduction of GW4064-induced ileal expression of Fgf15. In a diet-induced NAFLD study, low-fat diet (LFD) fed mice administered myclobutanil displayed decreased FXR activity in the liver and ileum, while high-fat-high-sugar-diet (HFHSD) fed mice showed an increase in hepatic FXR activity and an induction of target genes regulated by constitutive androstane receptor and/or pregnane X receptor. Our work demonstrates Myclobutanil inhibits FXR activity and modulates FXR activity differentially in mice fed LFD or HFHSD. Our studies suggest the importance of understanding how Myclobutanil could contribute to BA dysregulation in disease states such as NAFLD.
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Affiliation(s)
- Rulaiha Taylor
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ 08854, USA.,Environmental and Occupational Health Science Institute, Rutgers University, Piscataway, NJ 08854, USA.,Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA
| | - Laura Armstrong
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ 08854, USA.,Environmental and Occupational Health Science Institute, Rutgers University, Piscataway, NJ 08854, USA.,Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA
| | - Anisha Bhattacharya
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ 08854, USA
| | - Zakiyah Henry
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ 08854, USA.,Environmental and Occupational Health Science Institute, Rutgers University, Piscataway, NJ 08854, USA.,Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA
| | - Anita Brinker
- Environmental and Occupational Health Science Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Brian Buckley
- Environmental and Occupational Health Science Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Bo Kong
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ 08854, USA.,Environmental and Occupational Health Science Institute, Rutgers University, Piscataway, NJ 08854, USA.,Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA
| | - Grace Guo
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ 08854, USA.,Environmental and Occupational Health Science Institute, Rutgers University, Piscataway, NJ 08854, USA.,Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA.,VA New Jersey Health Care System, Veterans Administration Medical Center, East Orange, NJ 07017, USA
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7
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Pan S, Guo Y, Yu W, Zhang J, Qiao X, Li L, Xu P, Zhai Y. Constitutive Androstane Receptor Agonist, TCPOBOP: Maternal Exposure Impairs the Growth and Development of Female Offspring in Mice. Int J Mol Sci 2023; 24:2602. [PMID: 36768963 PMCID: PMC9917268 DOI: 10.3390/ijms24032602] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
Environmental chemicals, which are known to impact offspring health, have become a public concern. Constitutive activated receptor (CAR) is activated by various environmental chemicals and participates in xenobiotic metabolism. Here, we described the effects of maternal exposure to the CAR-specific ligand 1,4-bis[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP, TC) on offspring health outcomes. Maternal TC exposure exhibited a stronger inhibition of body weight in 3-week-old and 8-week-old first-generation (F1) offspring female mice compared to controls. Further, maternal TC exposure obtained a strong increase in hepatic drug-metabolizing enzyme expression in 3-week-old female mice that persisted into 8-week-old adulthood. Interestingly, we observed distorted intestinal morphological features in 8-week-old F1 female mice in the TC-exposed group. Moreover, maternal TC exposure triggered a loss of intestinal barrier integrity by reducing the expression of intestinal tight junction proteins. Accordingly, maternal exposure to TC down-regulated serum triglyceride levels as well as decreased the expression of intestinal lipid uptake and transport marker genes. Mechanistically, maternal TC exposure activated the intestinal inflammatory response and disrupted the antioxidant system in the offspring female mice, thereby impeding the intestinal absorption of nutrients and seriously threatening offspring health. Altogether, these findings highlight that the effects of maternal TC exposure on offspring toxicity could not be ignored.
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Affiliation(s)
- Shijia Pan
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Yuan Guo
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Wen Yu
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Jia Zhang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Xiaoxiao Qiao
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Letong Li
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Pengfei Xu
- School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yonggong Zhai
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China
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8
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Pan S, Guo Y, Yu W, Hong F, Qiao X, Zhang J, Xu P, Zhai Y. Environmental chemical TCPOBOP disrupts milk lipid homeostasis during pregnancy and lactation. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 249:114463. [PMID: 38321682 DOI: 10.1016/j.ecoenv.2022.114463] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 02/08/2024]
Abstract
Humans are exposed to different kinds of environmental contaminants or drugs throughout their lifetimes. The widespread presence of these compounds has raised concerns about the consequent adverse effects on lactating women. The constitutive androstane receptor (CAR, Nr1i3) is known as a xenobiotic sensor for environmental pollution or drugs. In this study, the model environmental chemical 1, 4-bis [2-(3, 5-dichloropyridyloxy)] benzene, TCPOBOP (TC), which is a highly specific agonist of CAR, was used to investigate the effects of exogenous exposure on lactation function and offspring health in mice. The results revealed that TC exposure decreased the proliferation of mammary epithelial cells during pregnancy. This deficiency further compromised lobular-alveolar structures, resulting in alveolar cell apoptosis, as well as premature stoppage of the lactation cycle and aberrant lactation. Furthermore, TC exposure significantly altered the size and number of milk lipid droplets, suggesting that TC exposure inhibits milk lipid synthesis. Additionally, TC exposure interfered with the milk lipid metabolism network, resulting in the inability of TC-exposed mice to efficiently secrete nutrients and feed their offspring. These findings demonstrated that restricted synthesis and secretion of milk lipids would indirectly block mammary gland form and function, which explained the possible reasons for lactation failure and retarded offspring growth.
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Affiliation(s)
- Shijia Pan
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China; Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
| | - Yuan Guo
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China; Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
| | - Wen Yu
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China; Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
| | - Fan Hong
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China; Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
| | - Xiaoxiao Qiao
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China; Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
| | - Jia Zhang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China; Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
| | - Pengfei Xu
- School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China; Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Yonggong Zhai
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China; Key Laboratory for Cell Proliferation and Regulation Biology of State Education Ministry, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
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9
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Corton JC, Lee JS, Liu J, Ren H, Vallanat B, DeVito M. Determinants of gene expression in the human liver: Impact of aging and sex on xenobiotic metabolism. Exp Gerontol 2022; 169:111976. [PMID: 36244585 PMCID: PMC10586520 DOI: 10.1016/j.exger.2022.111976] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 12/15/2022]
Abstract
There is a need to characterize the potential susceptibility of older adults to toxicity from environmental chemical exposures. Liver xenobiotic metabolizing enzymes (XMEs) play important roles in detoxifying and eliminating xenobiotics. We examined global gene expression in the livers of young (21-45 years) and old (69+ years) men and women. Differentially expressed genes (DEG) were identified using two-way ANOVA (p ≤ 0.05). We identified 1437 and 1670 DEGs between young and old groups in men and women, respectively. Only a minor number of the total number of genes overlapped (146 genes). Aging increased or decreased pathways involved in inflammation and intermediary metabolism, respectively. Aging led to numerous changes in the expression of XME genes or genes known to control their expression (~90 genes). Out of 10 cytochrome P450s activities examined, there were increased activities of CYP1A2 and CYP2C9 enzymes in the old groups. We also identified sex-dependent genes that were more numerous in the young group (1065) than in the old group (202) and included changes in XMEs. These studies indicate that the livers from aging humans when compared to younger adults exhibit changes in XMEs that may lead to differences in the metabolism of xenobiotics.
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Affiliation(s)
- J Christopher Corton
- Center for Computational Toxicology and Exposure, US EPA, Research Triangle Park, NC 27711, United States of America.
| | - Janice S Lee
- Center for Public Health and Environmental Assessment, US EPA, Research Triangle Park, NC 27711, United States of America.
| | - Jie Liu
- Center for Computational Toxicology and Exposure, US EPA, Research Triangle Park, NC 27711, United States of America.
| | - Hongzu Ren
- Center for Public Health and Environmental Assessment, US EPA, Research Triangle Park, NC 27711, United States of America.
| | - Beena Vallanat
- Center for Computational Toxicology and Exposure, US EPA, Research Triangle Park, NC 27711, United States of America.
| | - Michael DeVito
- Center for Computational Toxicology and Exposure, US EPA, Research Triangle Park, NC 27711, United States of America.
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10
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Lim JJ, Suh Y, Faustman EM, Cui JY. Perfluorinated Carboxylic Acids with Increasing Carbon Chain Lengths Upregulate Amino Acid Transporters and Modulate Compensatory Response of Xenobiotic Transporters in HepaRG Cells. Drug Metab Dispos 2022; 50:1396-1413. [PMID: 34857530 PMCID: PMC9513853 DOI: 10.1124/dmd.121.000477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 11/23/2021] [Indexed: 12/16/2022] Open
Abstract
Perfluorinated carboxylic acids (PFCAs) are widespread environmental pollutants for which human exposure has been documented. PFCAs at high doses are known to regulate xenobiotic transporters partly through peroxisome proliferator-activated receptor alpha (PPARα) and constitutive androstane receptor (CAR) in rodent models. Less is known regarding how various PFCAs at a lower concentration modulate transporters for endogenous substrates, such as amino acids in human hepatocytes. Such studies are of particular importance because amino acids are involved in chemical detoxification, and their transport system may serve as a promising therapeutic target for structurally similar xenobiotics. The focus of this study was to further elucidate how PFCAs modulate transporters involved in intermediary metabolism and xenobiotic biotransformation. We tested the hepatic transcriptomic response of HepaRG cells exposed to 45 μM of perfluorooctanoic acid, perfluorononanoic acid, or perfluorodecanoic acid in triplicates for 24 hours (vehicle: 0.1% DMSO), as well as the prototypical ligands for PPARα (WY-14643, 45 μM) and CAR (6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime [CITCO], 2 μM). PFCAs with increasing carbon chain lengths (C8-C10) regulated more liver genes, with amino acid metabolism and transport ranked among the top enriched pathways and PFDA ranked as the most potent PFCA tested. Genes encoding amino acid transporters, which are essential for protein synthesis, were novel inducible targets by all three PFCAs, suggesting a potentially protective mechanism to reduce further toxic insults. None of the transporter regulations appeared to be through PPARα or CAR but potential involvement of nuclear factor erythroid 2-related factor 2 is noted for all 3 PFCAs. In conclusion, PFCAs with increasing carbon chain lengths up-regulate amino acid transporters and modulate xenobiotic transporters to limit further toxic exposures in HepaRG cells. SIGNIFICANCE STATEMENT: Little is known regarding how various perfluorinated carboxylic acids modulate the transporters for endogenous substrates in human liver cells. Using HepaRG cells, this study is among the first to show that perfluorinated carboxylic acids with increasing carbon chain lengths upregulate amino acid transporters, which are essential for protein synthesis, and modulate xenobiotic transporters to limit further toxic exposures at concentrations lower than what was used in the literature.
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Affiliation(s)
- Joe Jongpyo Lim
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Youjun Suh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Elaine M Faustman
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Julia Yue Cui
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
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11
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Corton JC, Mitchell CA, Auerbach S, Bushel P, Ellinger-Ziegelbauer H, Escobar PA, Froetschl R, Harrill AH, Johnson K, Klaunig JE, Pandiri AR, Podtelezhnikov AA, Rager JE, Tanis KQ, van der Laan JW, Vespa A, Yauk CL, Pettit SD, Sistare FD. A Collaborative Initiative to Establish Genomic Biomarkers for Assessing Tumorigenic Potential to Reduce Reliance on Conventional Rodent Carcinogenicity Studies. Toxicol Sci 2022; 188:4-16. [PMID: 35404422 PMCID: PMC9238304 DOI: 10.1093/toxsci/kfac041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
There is growing recognition across broad sectors of the scientific community that use of genomic biomarkers has the potential to reduce the need for conventional rodent carcinogenicity studies of industrial chemicals, agrochemicals, and pharmaceuticals through a weight-of-evidence approach. These biomarkers fall into 2 major categories: (1) sets of gene transcripts that can identify distinct tumorigenic mechanisms of action; and (2) cancer driver gene mutations indicative of rapidly expanding growth-advantaged clonal cell populations. This call-to-action article describes a collaborative approach launched to develop and qualify biomarker gene expression panels that measure widely accepted molecular pathways linked to tumorigenesis and their activation levels to predict tumorigenic doses of chemicals from short-term exposures. Growing evidence suggests that application of such biomarker panels in short-term exposure rodent studies can identify both tumorigenic hazard and tumorigenic activation levels for chemical-induced carcinogenicity. In the future, this approach will be expanded to include methodologies examining mutations in key cancer driver gene mutation hotspots as biomarkers of both genotoxic and nongenotoxic chemical tumor risk. Analytical, technical, and biological validation studies of these complementary genomic tools are being undertaken by multisector and multidisciplinary collaborative teams within the Health and Environmental Sciences Institute. Success from these efforts will facilitate the transition from current heavy reliance on conventional 2-year rodent carcinogenicity studies to more rapid animal- and resource-sparing approaches for mechanism-based carcinogenicity evaluation supporting internal and regulatory decision-making.
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Affiliation(s)
- J Christopher Corton
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Constance A Mitchell
- Health and Environmental Sciences Institute, Washington, District of Columbia, USA
| | - Scott Auerbach
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Pierre Bushel
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | | | - Patricia A Escobar
- Safety Assessment and Laboratory Animal Resources, Merck Sharp & Dohme Corp, West Point, Pennsylvania, USA
| | - Roland Froetschl
- BfArM-Bundesinstitut für Arzneimittel und Medizinprodukte, Federal Institute for Drugs and Medical Devices, Bonn, Germany
| | - Alison H Harrill
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | | | - James E Klaunig
- Laboratory of Investigative Toxicology and Pathology, Department of Environmental and Occupational Health, Indiana School of Public Health, Indiana University, Bloomington, Indiana, USA
| | - Arun R Pandiri
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | | | - Julia E Rager
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Keith Q Tanis
- Safety Assessment and Laboratory Animal Resources, Merck Sharp & Dohme Corp, West Point, Pennsylvania, USA
| | - Jan Willem van der Laan
- Section on Pharmacology, Toxicology and Kinetics, Medicines Evaluation Board, Utrecht, The Netherlands
| | - Alisa Vespa
- Therapeutic Products Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Carole L Yauk
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Syril D Pettit
- Health and Environmental Sciences Institute, Washington, District of Columbia, USA
| | - Frank D Sistare
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
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12
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Corton JC, Liu J, Williams A, Cho E, Yauk CL. A gene expression biomarker identifies inhibitors of two classes of epigenome effectors in a human microarray compendium. Chem Biol Interact 2022; 365:110032. [PMID: 35777453 DOI: 10.1016/j.cbi.2022.110032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 11/03/2022]
Abstract
Biomarkers predictive of molecular and toxicological effects are needed to interpret emerging high-throughput transcriptomics (HTTr) data streams. To address the limited approaches available for identifying epigenotoxicants, we previously developed and validated an 81-gene biomarker that accurately predicts histone deacetylase inhibition (HDACi) in transcript profiles derived from chemically-treated TK6 cells. In the present study, we sought to determine if this biomarker (TGx-HDACi) could be used to identify HDACi chemicals in other cell lines using the Running Fisher correlation test. Using microarray comparisons derived from human cells exposed to HDACi, we found considerable heterogeneity in correlation with the TGx-HDACi biomarker dependent on chemical exposure conditions and tissue from which the cell line was derived. Using a defined set of conditions that overlapped with our earlier study, the biomarker was able to accurately identify HDACi chemicals (90-100% balanced accuracy). In an in silico screen of 2427 chemicals in 9660 chemical versus control comparisons, the biomarker coupled with the Running Fisher test was able to identify 14 additional HDACi chemicals as well as other chemicals not previously associated with HDACi. Most notable were 12 inhibitors of bromodomain (BRD) and extraterminal (BET) family proteins including BRD4 that bind to acetylated histones. The BET protein inhibitors could be distinguished from the HDACi based on differences in the expression of a small set of biomarker genes. Our results indicate that the TGx-HDACi biomarker will be useful for identifying inhibitors of two classes of epigenome effectors in HTTr screening studies.
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Affiliation(s)
- J Christopher Corton
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC, 27711, USA.
| | - Jie Liu
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC, 27711, USA.
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada.
| | - Eunnara Cho
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada.
| | - Carole L Yauk
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
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13
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Corton JC, Liu J, Kleinstreuer N, Gwinn MR, Ryan N. Towards replacement of animal tests with in vitro assays: a gene expression biomarker predicts in vitro and in vivo estrogen receptor activity. Chem Biol Interact 2022; 363:109995. [PMID: 35697134 DOI: 10.1016/j.cbi.2022.109995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/02/2022] [Accepted: 05/24/2022] [Indexed: 11/18/2022]
Abstract
High-throughput transcriptomics (HTTr) has the potential to support efforts to reduce or replace some animal tests. In past studies, we described a computational approach utilizing a gene expression biomarker consisting of 46 genes to predict estrogen receptor (ER) activity after chemical exposure in ER-positive human breast cancer cells including the MCF-7 cell line. We hypothesized that the biomarker model could identify ER activities of chemicals examined by Endocrine Disruptor Screening Program (EDSP) Tier 1 screening assays in which transcript profiles of the same chemicals were examined in MCF-7 cells. For the 62 chemicals examined including 5 chemicals examined in this study using RNA-Seq, the ER biomarker model accuracy was 1) 97% for in vitro reference chemicals, 2) 76-85% for guideline uterotrophic assays, and 3) 87-88% for guideline and nonguideline uterotrophic assays. For the same chemicals, these accuracies were similar or slightly better than those of the ToxCast ER model based on 18 in vitro assays. The performance of the ER biomarker model indicates that HTTr interpreted using the ER biomarker correctly identifies active and inactive ER reference chemicals. As part of the HTTr screening program the approach could rapidly identify chemicals with potential ER bioactivities for additional screening and testing.
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Affiliation(s)
- J Christopher Corton
- Center for Computational Toxicology and Exposure, US-EPA, Research Triangle Park, NC, 27711, USA.
| | - Jie Liu
- Center for Computational Toxicology and Exposure, US-EPA, Research Triangle Park, NC, 27711, USA.
| | - Nicole Kleinstreuer
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27711, USA.
| | - Maureen R Gwinn
- Center for Computational Toxicology and Exposure, US-EPA, Research Triangle Park, NC, 27711, USA.
| | - Natalia Ryan
- Oak Ridge Institute for Science and Education (ORISE), Research Triangle Park, NC, 27711, USA.
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14
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Korunes KL, Liu J, Huang R, Xia M, Houck KA, Corton JC. A gene expression biomarker for predictive toxicology to identify chemical modulators of NF-κB. PLoS One 2022; 17:e0261854. [PMID: 35108274 PMCID: PMC8809623 DOI: 10.1371/journal.pone.0261854] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/12/2021] [Indexed: 11/29/2022] Open
Abstract
The nuclear factor-kappa B (NF-κB) is a transcription factor with important roles in inflammation, immune response, and oncogenesis. Dysregulation of NF-κB signaling is associated with inflammation and certain cancers. We developed a gene expression biomarker predictive of NF-κB modulation and used the biomarker to screen a large compendia of gene expression data. The biomarker consists of 108 genes responsive to tumor necrosis factor α in the absence but not the presence of IκB, an inhibitor of NF-κB. Using a set of 450 profiles from cells treated with immunomodulatory factors with known NF-κB activity, the balanced accuracy for prediction of NF-κB activation was > 90%. The biomarker was used to screen a microarray compendium consisting of 12,061 microarray comparisons from human cells exposed to 2,672 individual chemicals to identify chemicals that could cause toxic effects through NF-κB. There were 215 and 49 chemicals that were identified as putative or known NF-κB activators or suppressors, respectively. NF-κB activators were also identified using two high-throughput screening assays; 165 out of the ~3,800 chemicals (ToxCast assay) and 55 out of ~7,500 unique compounds (Tox21 assay) were identified as potential activators. A set of 32 chemicals not previously associated with NF-κB activation and which partially overlapped between the different screens were selected for validation in wild-type and NFKB1-null HeLa cells. Using RT-qPCR and targeted RNA-Seq, 31 of the 32 chemicals were confirmed to be NF-κB activators. These results comprehensively identify a set of chemicals that could cause toxic effects through NF-κB.
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Affiliation(s)
- Katharine L. Korunes
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, North Carolina, United States of America
- Biology Department, Duke University, Durham, North Carolina, United States of America
| | - Jie Liu
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, North Carolina, United States of America
| | - Ruili Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Menghang Xia
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Keith A. Houck
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, North Carolina, United States of America
| | - J. Christopher Corton
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, North Carolina, United States of America
- * E-mail:
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15
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Rooney J, Wehmas LC, Ryan N, Chorley BN, Hester SD, Kenyon EM, Schmid JE, George BJ, Hughes MF, Sey YM, Tennant AH, Simmons JE, Wood CE, Corton JC. Genomic comparisons between hepatocarcinogenic and non-hepatocarcinogenic organophosphate insecticides in the mouse liver. Toxicology 2022; 465:153046. [PMID: 34813904 DOI: 10.1016/j.tox.2021.153046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 11/12/2021] [Accepted: 11/17/2021] [Indexed: 11/27/2022]
Abstract
Short-term biomarkers of toxicity have an increasingly important role in the screening and prioritization of new chemicals. In this study, we examined early indicators of liver toxicity for three reference organophosphate (OP) chemicals, which are among the most widely used insecticides in the world. The OP methidathion was previously shown to increase the incidence of liver toxicity, including hepatocellular tumors, in male mice. To provide insights into the adverse outcome pathway (AOP) that underlies these tumors, effects of methidathion in the male mouse liver were examined after 7 and 28 day exposures and compared to those of two other OPs that either do not increase (fenthion) or possibly suppress liver cancer (parathion) in mice. None of the chemicals caused increases in liver weight/body weight or histopathological changes in the liver. Parathion decreased liver cell proliferation after 7 and 28 days while the other chemicals had no effects. There was no evidence for hepatotoxicity in any of the treatment groups. Full-genome microarray analysis of the livers from the 7 and 28 day treatments demonstrated that methidathion and fenthion regulated a large number of overlapping genes, while parathion regulated a unique set of genes. Examination of cytochrome P450 enzyme activities and use of predictive gene expression biomarkers found no consistent evidence for activation of AhR, CAR, PXR, or PPARα. Parathion suppressed the male-specific gene expression pattern through STAT5b, similar to genetic and dietary conditions that decrease liver tumor incidence in mice. Overall, these findings indicate that methidathion causes liver cancer by a mechanism that does not involve common mechanisms of liver cancer induction.
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Affiliation(s)
- John Rooney
- Oak Ridge Institute for Science and Education (ORISE) Research Participant at US EPA, Office of Research and Development, Center for Computational Toxicology and Exposure (formerly NHEERL), Research Triangle Park, NC, 27711, United States; National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States(3).
| | - Leah C Wehmas
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Natalia Ryan
- Oak Ridge Institute for Science and Education (ORISE) Research Participant at US EPA, Office of Research and Development, Center for Computational Toxicology and Exposure (formerly NHEERL), Research Triangle Park, NC, 27711, United States; National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States(3).
| | - Brian N Chorley
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Susan D Hester
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Elaina M Kenyon
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Judith E Schmid
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States(3).
| | - Barbara Jane George
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Michael F Hughes
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Yusupha M Sey
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Alan H Tennant
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Jane Ellen Simmons
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Charles E Wood
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States(3).
| | - J Christopher Corton
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
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16
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Koga T, Peters JM. Targeting Peroxisome Proliferator-Activated Receptor-β/δ (PPARβ/δ) for the Treatment or Prevention of Alcoholic Liver Disease. Biol Pharm Bull 2021; 44:1598-1606. [PMID: 34719638 DOI: 10.1248/bpb.b21-00486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Excessive, chronic alcohol consumption can lead to alcoholic liver disease. The etiology of alcoholic liver disease is multifactorial and is influenced by alterations in gene expression and changes in fatty acid metabolism, oxidative stress, and insulin resistance. These events can lead to steatosis, fibrosis, and eventually to cirrhosis and liver cancer. Many of these functions are regulated by peroxisome proliferator-activated receptors (PPARs). Thus, it is not surprising that PPARs can modulate the mechanisms that cause alcoholic liver disease. While the roles of PPARα and PPARγ are clearer, the role of PPARβ/δ in alcoholic liver disease requires further clarification. This review summarizes the current understanding based on recent studies that indicate that PPARβ/δ can likely be targeted for the treatment and/or the prevention of alcoholic liver disease.
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Affiliation(s)
- Takayuki Koga
- Laboratory of Hygienic Chemistry, Department of Health Science and Hygiene, Daiichi University of Pharmacy
| | - Jeffrey M Peters
- Department of Veterinary and Biomedical Sciences and the Center of Molecular Toxicology and Carcinogenesis, The Pennsylvania State University
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17
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Cervantes PW, Corton JC. A Gene Expression Biomarker Predicts Heat Shock Factor 1 Activation in a Gene Expression Compendium. Chem Res Toxicol 2021; 34:1721-1737. [PMID: 34170685 DOI: 10.1021/acs.chemrestox.0c00510] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The United States Environmental Protection Agency (US EPA) recently developed a tiered testing strategy to use advances in high-throughput transcriptomics (HTTr) testing to identify molecular targets of thousands of environmental chemicals that can be linked to adverse outcomes. Here, we describe a method that uses a gene expression biomarker to predict chemical activation of heat shock factor 1 (HSF1), a transcription factor critical for proteome maintenance. The HSF1 biomarker was built from transcript profiles derived from A375 cells exposed to a HSF1-activating heat shock protein (HSP) 90 inhibitor in the presence or absence of HSF1 expression. The resultant 44 identified genes included those that (1) are dependent on HSF1 for regulation, (2) have direct interactions with HSF1 assessed by ChIP-Seq, and (3) are in the molecular chaperone family. To test for accuracy, the biomarker was compared in a pairwise manner to gene lists derived from treatments with known HSF1 activity (HSP and proteasomal inhibitors) using the correlation-based Running Fisher test; the balanced accuracy for prediction was 96%. A microarray compendium consisting of 12,092 microarray comparisons from human cells exposed to 2670 individual chemicals was screened using our approach; 112 and 19 chemicals were identified as putative HSF1 activators or suppressors, respectively, and most appear to be novel modulators. A large percentage of the chemical treatments that induced HSF1 also induced oxidant-activated NRF2 (∼46%). For five compounds or mixtures, we found that NRF2 activation occurred at lower concentrations or at earlier times than HSF1 activation, supporting the concept of a tiered cellular protection system dependent on the level of chemical-induced stress. The approach described here could be used to identify environmentally relevant chemical HSF1 activators in HTTr data sets.
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Affiliation(s)
- Patrick W Cervantes
- Center for Computational Toxicology and Exposure, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States.,Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison 53706, Wisconsin, United States
| | - J Christopher Corton
- Center for Computational Toxicology and Exposure, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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18
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Yamada T, Cohen SM, Lake BG. Critical evaluation of the human relevance of the mode of action for rodent liver tumor formation by activators of the constitutive androstane receptor (CAR). Crit Rev Toxicol 2021; 51:373-394. [PMID: 34264181 DOI: 10.1080/10408444.2021.1939654] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Many nongenotoxic chemicals have been shown to produce liver tumors in mice and/or rats by a mode of action (MOA) involving activation of the constitutive androstane receptor (CAR). Studies with phenobarbital (PB) and other compounds have identified the key events for this MOA: CAR activation; increased hepatocellular proliferation; altered foci formation; and ultimately the development of adenomas/carcinomas. In terms of human relevance, the pivotal species difference is that CAR activators are mitogenic agents in mouse and rat hepatocytes, but they do not stimulate increased hepatocellular proliferation in humans. This conclusion is supported by substantial in vitro studies with cultured rodent and human hepatocytes and also by in vivo studies with chimeric mice with human hepatocytes. Examination of the literature reveals many similarities in the hepatic effects and species differences between activators of rodent CAR and the peroxisome proliferator-activated receptor alpha (PPARα), with PPARα activators also not being mitogenic agents in human hepatocytes. Overall, a critical analysis of the available data demonstrates that the established MOA for rodent liver tumor formation by PB and other CAR activators is qualitatively not plausible for humans. This conclusion is supported by data from several human epidemiology studies.
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Affiliation(s)
- Tomoya Yamada
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd., Osaka, Japan
| | - Samuel M Cohen
- Department of Pathology and Microbiology, Havlik-Wall Professor of Oncology, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, NE, USA
| | - Brian G Lake
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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19
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Rooney J, Ryan N, Liu J, Houtman R, van Beuningen R, Hsieh JH, Chang G, Chen S, Christopher Corton J. A Gene Expression Biomarker Identifies Chemical Modulators of Estrogen Receptor α in an MCF-7 Microarray Compendium. Chem Res Toxicol 2021; 34:313-329. [PMID: 33405908 PMCID: PMC10683854 DOI: 10.1021/acs.chemrestox.0c00243] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Identification of chemicals that affect hormone-regulated systems will help to predict endocrine disruption. In our previous study, a 46 gene biomarker was found to be an accurate predictor of estrogen receptor (ER) α modulation in chemically treated MCF-7 cells. Here, potential ERα modulators were identified using the biomarker by screening a microarray compendium consisting of ∼1600 gene expression comparisons representing exposure to ∼1200 chemicals. A total of ∼170 chemicals were identified as potential ERα modulators. In the Connectivity Map 2.0 collection, 75 and 39 chemicals were predicted to activate or suppress ERα, and they included 12 and six known ERα agonists and antagonists/selective ERα modulators, respectively. Nineteen and eight of the total number were also identified as active in an ERα transactivation assay carried out in an MCF-7-derived cell line used to screen the Tox21 10K chemical library in agonist or antagonist modes, respectively. Chemicals predicted to modulate ERα in MCF-7 cells were examined further using global and targeted gene expression in wild-type and ERα-null cells, transactivation assays, and cell-free ERα coregulator interaction assays. Environmental chemicals classified as weak and very weak agonists were confirmed to activate ERα including apigenin, kaempferol, and oxybenzone. Novel activators included digoxin, nabumetone, ivermectin, and six progestins. Novel suppressors included emetine, mifepristone, niclosamide, and proscillaridin. Our strategy will be useful to identify environmentally relevant ERα modulators in future high-throughput transcriptomic screens.
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Affiliation(s)
- John Rooney
- Center for Computational Toxicology and Exposure, US-EPA, Research Triangle Park, NC 27711
- Present address: Integrated Lab Services, Research Triangle Park, NC
| | - Natalia Ryan
- Center for Computational Toxicology and Exposure, US-EPA, Research Triangle Park, NC 27711
- Present address: Bayer Crop Science, Research Triangle Park, NC
| | - Jie Liu
- Center for Computational Toxicology and Exposure, US-EPA, Research Triangle Park, NC 27711
| | - René Houtman
- PamGene International B.V., Den Bosch, The Netherlands
- Present address: Precision Medicine Lab, Oss, The Netherlands
| | | | - Jui-Hua Hsieh
- Kelly Government Solutions, Research Triangle Park, North Carolina
| | - Gregory Chang
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte,California 91010
| | - Shiuan Chen
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte,California 91010
| | - J. Christopher Corton
- Center for Computational Toxicology and Exposure, US-EPA, Research Triangle Park, NC 27711
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20
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Bae SDW, Nguyen R, Qiao L, George J. Role of the constitutive androstane receptor (CAR) in human liver cancer. Biochim Biophys Acta Rev Cancer 2021; 1875:188516. [PMID: 33529650 DOI: 10.1016/j.bbcan.2021.188516] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND The constitutive androstane receptor (CAR) is a member of the nuclear receptor superfamily (subfamily 1, group I, member 3, also known as NR1I3) that is almost exclusively expressed in the liver. CAR interacts with key signalling pathways such as those involved in drug, energy and bilirubin metabolism. In mouse models, activation of CAR leads to tumorigenesis by inducing pro-proliferative and anti-apoptotic signalling. However, many previous reports have shown species differences between CAR activity in animal models and humans. Recent studies have demonstrated that the mode of action of CAR in rodent liver tumorigenesis is not applicable to humans. Despite this, many studies still continue to study the role of CAR in animal models, hence, there is a need to further explore the role of CAR in human diseases particularly cancers. While there is limited evidence for a role of CAR in human cancers, some studies have proposed a tumour-suppressive role of CAR in liver cancer. In addition, recent studies exploring CAR in human livers demonstrated a hepato-protective role for CAR in and more specifically, its ability to drive differentiation and liver regeneration. This review will discuss the role of CAR in liver cancer, with a focus on species differences and its emerging, tumour-suppressive role in liver cancer and its role in the regulation of liver cancer stem cells.
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Affiliation(s)
- Sarah Da Won Bae
- Storr Liver Centre, Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, NSW 2145, Australia
| | - Romario Nguyen
- Storr Liver Centre, Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, NSW 2145, Australia
| | - Liang Qiao
- Storr Liver Centre, Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, NSW 2145, Australia.
| | - Jacob George
- Storr Liver Centre, Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, NSW 2145, Australia.
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21
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Diethelm-Varela B, Kumar A, Lynch C, Imler GH, Deschamps JR, Li Y, Xia M, MacKerell AD, Xue F. Stereoisomerization of human constitutive androstane receptor agonist CITCO. Tetrahedron 2021. [DOI: 10.1016/j.tet.2020.131886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Oliviero F, Lukowicz C, Boussadia B, Forner-Piquer I, Pascussi JM, Marchi N, Mselli-Lakhal L. Constitutive Androstane Receptor: A Peripheral and a Neurovascular Stress or Environmental Sensor. Cells 2020; 9:E2426. [PMID: 33171992 PMCID: PMC7694609 DOI: 10.3390/cells9112426] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 10/27/2020] [Accepted: 11/02/2020] [Indexed: 12/11/2022] Open
Abstract
Xenobiotic nuclear receptors (NR) are intracellular players involved in an increasing number of physiological processes. Examined and characterized in peripheral organs where they govern metabolic, transport and detoxification mechanisms, accumulating data suggest a functional expression of specific NR at the neurovascular unit (NVU). Here, we focus on the Constitutive Androstane Receptor (CAR), expressed in detoxifying organs such as the liver, intestines and kidneys. By direct and indirect activation, CAR is implicated in hepatic detoxification of xenobiotics, environmental contaminants, and endogenous molecules (bilirubin, bile acids). Importantly, CAR participates in physiological stress adaptation responses, hormonal and energy homeostasis due to glucose and lipid sensing. We next analyze the emerging evidence supporting a role of CAR in NVU cells including the blood-brain barrier (BBB), a key vascular interface regulating communications between the brain and the periphery. We address the emerging concept of how CAR may regulate specific P450 cytochromes at the NVU and the associated relevance to brain diseases. A clear understanding of how CAR engages during pathological conditions could enable new mechanistic, and perhaps pharmacological, entry-points within a peripheral-brain axis.
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Affiliation(s)
- Fabiana Oliviero
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (F.O.); (C.L.)
| | - Céline Lukowicz
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (F.O.); (C.L.)
| | - Badreddine Boussadia
- Cerebrovascular and Glia Research, Institute of Functional Genomics (UMR 5203 CNRS–U 1191 INSERM, University of Montpellier), 34094 Montpellier, France; (B.B.); (I.F.-P.); (J.-M.P.)
| | - Isabel Forner-Piquer
- Cerebrovascular and Glia Research, Institute of Functional Genomics (UMR 5203 CNRS–U 1191 INSERM, University of Montpellier), 34094 Montpellier, France; (B.B.); (I.F.-P.); (J.-M.P.)
| | - Jean-Marc Pascussi
- Cerebrovascular and Glia Research, Institute of Functional Genomics (UMR 5203 CNRS–U 1191 INSERM, University of Montpellier), 34094 Montpellier, France; (B.B.); (I.F.-P.); (J.-M.P.)
| | - Nicola Marchi
- Cerebrovascular and Glia Research, Institute of Functional Genomics (UMR 5203 CNRS–U 1191 INSERM, University of Montpellier), 34094 Montpellier, France; (B.B.); (I.F.-P.); (J.-M.P.)
| | - Laila Mselli-Lakhal
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (F.O.); (C.L.)
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23
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Corton JC, Korunes KL, Abedini J, El-Masri H, Brown J, Paul-Friedman K, Liu Y, Martini C, He S, Rooney J. Thresholds Derived From Common Measures in Rat Studies Are Predictive of Liver Tumorigenic Chemicals. Toxicol Pathol 2020; 48:857-874. [DOI: 10.1177/0192623320960412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We hypothesized that typical tissue and clinical chemistry (ClinChem) end points measured in rat toxicity studies exhibit chemical-independent biological thresholds beyond which cancer occurs. Using the rat in vivo TG-GATES study, 75 chemicals were examined across chemical-dose-time comparisons that could be linked to liver tumor outcomes. Thresholds for liver weight to body weight (LW/BW) and 21 serum ClinChem end points were defined as the maximum and minimum values for those exposures that did not lead to liver tumors in rats. Upper thresholds were identified for LW/BW (117%), aspartate aminotransferase (195%), alanine aminotransferase (141%), alkaline phosphatase (152%), and total bilirubin (115%), and lower thresholds were identified for phospholipids (82%), relative albumin (93%), total cholesterol (82%), and total protein (94%). Thresholds derived from the TG-GATES data set were consistent across other acute and subchronic rat studies. A training set of ClinChem and LW/BW thresholds derived from a 38 chemical training set from TG-GATES was predictive of liver tumor outcomes for a test set of 37 independent TG-GATES chemicals (91%). The thresholds were most predictive when applied to 7d treatments (98%). These findings provide support that biological thresholds for common end points in rodent studies can be used to predict chemical tumorigenic potential.
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Affiliation(s)
- J. Christopher Corton
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, USA
| | - Katharine L. Korunes
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Jaleh Abedini
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, USA
| | - Hisham El-Masri
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, USA
| | - Jason Brown
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, USA
| | - Katie Paul-Friedman
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, USA
| | - Ying Liu
- ASRC Federal, Research Triangle Park, NC, USA
| | | | - Shihan He
- ASRC Federal, Research Triangle Park, NC, USA
| | - John Rooney
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, USA
- Oak Ridge Institute for Science and Education (ORISE), National Health and Environmental Effects Research Laboratory (NHEERL), Office of Research and Development, U.S. Environmental Protection Agency (EPA), Research Triangle Park, NC, USA
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24
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Küblbeck J, Niskanen J, Honkakoski P. Metabolism-Disrupting Chemicals and the Constitutive Androstane Receptor CAR. Cells 2020; 9:E2306. [PMID: 33076503 PMCID: PMC7602645 DOI: 10.3390/cells9102306] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/13/2020] [Accepted: 10/13/2020] [Indexed: 02/07/2023] Open
Abstract
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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Affiliation(s)
- Jenni Küblbeck
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, FI-70210 Kuopio, Finland;
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70210 Kuopio, Finland;
| | - Jonna Niskanen
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70210 Kuopio, Finland;
| | - Paavo Honkakoski
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70210 Kuopio, Finland;
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Campus Box 7569, Chapel Hill, NC 27599-7569, USA
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25
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Lewis RW, Hill T, Corton JC. A set of six Gene expression biomarkers and their thresholds identify rat liver tumorigens in short-term assays. Toxicology 2020; 443:152547. [PMID: 32755643 PMCID: PMC10439517 DOI: 10.1016/j.tox.2020.152547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/23/2020] [Accepted: 07/28/2020] [Indexed: 02/01/2023]
Abstract
Traditional methods for cancer risk assessment are retrospective, resource-intensive, and not feasible for the vast majority of environmental chemicals. In earlier studies, we used a set of six biomarkers to accurately identify liver tumorigens in transcript profiles derived from chemically-treated rats using either a Toxicological Priority Index (ToxPi) approach or using derived biomarker thresholds for cancer. The biomarkers consisting of 7-113 genes are used to predict the most common liver cancer molecular initiating events: genotoxicity, cytotoxicity and activation of the xenobiotic receptors AhR, CAR, ER, and PPARα. In the present study, we apply and evaluate the performance of these methods for cancer prediction in an independent rat liver study of 44 chemicals (6 h-7d exposures) examined by Affymetrix arrays. In the first approach, ToxPi ranking of biomarker scores consistently gave the highest scores to tumorigenic chemical-dose pairs; balanced accuracies for identification of liver tumorigenic chemicals were up to 89 %. The second approach used tumorigenic thresholds derived in the present study or from our earlier study that were set at the maximum value for chemical-dose exposures without detectable liver tumor outcomes. Using these thresholds, balanced accuracies were up to 90 %. Both approaches identified all tumorigenic chemicals. Almost all of the tumorigenic chemicals activated more than one MIE. We also compared biomarker responses between two types of profiling platforms (Affymetrix full-genome array, TempO-Seq 1500+ array containing ∼2600 genes) and found that the lack of the full set of biomarker genes on the 1500+ array resulted in decreased ability to identify chemicals that activate the MIEs. Overall, these results demonstrate that predictive approaches based on the 6 biomarkers could be used in short-term assays to identify chemicals and their doses that induce liver tumors, the most common endpoint in rodent bioassays.
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Affiliation(s)
- Robert W Lewis
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, United States.
| | - Thomas Hill
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, United States; Oak Ridge Institute for Science and Education (ORISE) fellow Office of Research and Development, U.S. Environmental Protection Agency (EPA), Research Triangle Park, NC, United States.
| | - J Christopher Corton
- Center for Computational Toxicology and Exposure, U.S. EPA, Research Triangle Park, NC, United States.
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26
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Mining a human transcriptome database for chemical modulators of NRF2. PLoS One 2020; 15:e0239367. [PMID: 32986742 PMCID: PMC7521735 DOI: 10.1371/journal.pone.0239367] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 09/07/2020] [Indexed: 12/14/2022] Open
Abstract
Nuclear factor erythroid-2 related factor 2 (NRF2) encoded by the NFE2L2 gene is a transcription factor critical for protecting cells from chemically-induced oxidative stress. We developed computational procedures to identify chemical modulators of NRF2 in a large database of human microarray data. A gene expression biomarker was built from statistically-filtered gene lists derived from microarray experiments in primary human hepatocytes and cancer cell lines exposed to NRF2-activating chemicals (oltipraz, sulforaphane, CDDO-Im) or in which the NRF2 suppressor Keap1 was knocked down by siRNA. Directionally consistent biomarker genes were further filtered for those dependent on NRF2 using a microarray dataset from cells after NFE2L2 siRNA knockdown. The resulting 143-gene biomarker was evaluated as a predictive tool using the correlation-based Running Fisher algorithm. Using 59 gene expression comparisons from chemically-treated cells with known NRF2 activating potential, the biomarker gave a balanced accuracy of 93%. The biomarker was comprised of many well-known NRF2 target genes (AKR1B10, AKR1C1, NQO1, TXNRD1, SRXN1, GCLC, GCLM), 69% of which were found to be bound directly by NRF2 using ChIP-Seq. NRF2 activity was assessed across ~9840 microarray comparisons from ~1460 studies examining the effects of ~2260 chemicals in human cell lines. A total of 260 and 43 chemicals were found to activate or suppress NRF2, respectively, most of which have not been previously reported to modulate NRF2 activity. Using a NRF2-responsive reporter gene in HepG2 cells, we confirmed the activity of a set of chemicals predicted using the biomarker. The biomarker will be useful for future gene expression screening studies of environmentally-relevant chemicals.
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27
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Corton JC, Hill T, Sutherland JJ, Stevens JL, Rooney J. A Set of Six Gene Expression Biomarkers Identify Rat Liver Tumorigens in Short-term Assays. Toxicol Sci 2020; 177:11-26. [PMID: 32603430 PMCID: PMC8026143 DOI: 10.1093/toxsci/kfaa101] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Chemical-induced liver cancer occurs in rodents through well-characterized adverse outcome pathways. We hypothesized that measurement of the 6 most common molecular initiating events (MIEs) in liver cancer adverse outcome pathways in short-term assays using only gene expression will allow early identification of chemicals and their associated doses that are likely to be tumorigenic in the liver in 2-year bioassays. We tested this hypothesis using transcript data from a rat liver microarray compendium consisting of 2013 comparisons of 146 chemicals administered at doses with previously established effects on rat liver tumor induction. Five MIEs were measured using previously characterized gene expression biomarkers composed of gene sets predictive for genotoxicity and activation of 1 or more xenobiotic receptors (aryl hydrocarbon receptor, constitutive activated receptor, estrogen receptor, and peroxisome proliferator-activated receptor α). Because chronic injury can be important in tumorigenesis, we also developed a biomarker for cytotoxicity that had a 96% balanced accuracy. Characterization of the genes in each biomarker set using the unsupervised TXG-MAP network model demonstrated that the genes were associated with distinct functional coexpression modules. Using the Toxicological Priority Index to rank chemicals based on their ability to activate the MIEs showed that chemicals administered at tumorigenic doses clearly gave the highest ranked scores. Balanced accuracies using thresholds derived from either TG-GATES or DrugMatrix data sets to predict tumorigenicity in independent sets of chemicals were up to 93%. These results show that a MIE-directed approach using only gene expression biomarkers could be used in short-term assays to identify chemicals and their doses that cause tumors.
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Affiliation(s)
- J Christopher Corton
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina
| | - Thomas Hill
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina
- Oak Ridge Institute for Science and Education (ORISE)
| | | | - James L Stevens
- Indiana Biosciences Research Institute, Indianapolis, Indiana
- Paradox Found LLC, Apex, North Carolina
| | - John Rooney
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina
- Oak Ridge Institute for Science and Education (ORISE)
- Integrated Lab Services, Research Triangle Park, NC 27560
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28
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Hill T, Rooney J, Abedini J, El-Masri H, Wood CE, Corton JC. Gene Expression Thresholds Derived From Short-term Exposures Identify Rat Liver Tumorigens. Toxicol Sci 2020; 177:41-59. [PMID: 32603419 DOI: 10.1093/toxsci/kfaa102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Traditional methods for cancer risk assessment are resource-intensive, retrospective, and not feasible for the vast majority of environmental chemicals. In this study, we investigated whether quantitative genomic data from short-term studies may be used to set protective thresholds for potential tumorigenic effects. We hypothesized that gene expression biomarkers measuring activation of the key early events in established pathways for rodent liver cancer exhibit cross-chemical thresholds for tumorigenesis predictive for liver cancer risk. We defined biomarker thresholds for 6 major liver cancer pathways using training sets of chemicals with short-term genomic data (3-29 days of exposure) from the TG-GATES (n = 77 chemicals) and DrugMatrix (n = 86 chemicals) databases and then tested these thresholds within and between datasets. The 6 pathway biomarkers represented genotoxicity, cytotoxicity, and activation of xenobiotic, steroid, and lipid receptors (aryl hydrocarbon receptor, constitutive activated receptor, estrogen receptor, and peroxisome proliferator-activated receptor α). Thresholds were calculated as the maximum values derived from exposures without detectable liver tumor outcomes. We identified clear response values that were consistent across training and test sets. Thresholds derived from the TG-GATES training set were highly predictive (97%) in a test set of independent chemicals, whereas thresholds derived from the DrugMatrix study were 96%-97% predictive for the TG-GATES study. Threshold values derived from an abridged gene list (2/biomarker) also exhibited high predictive accuracy (91%-94%). These findings support the idea that early genomic changes can be used to establish threshold estimates or "molecular tipping points" that are predictive of later-life health outcomes.
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Affiliation(s)
- Thomas Hill
- Center for Computational Toxicology and Exposure.,Oak Ridge Institute for Science and Education (ORISE), NHEERL, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - John Rooney
- Center for Computational Toxicology and Exposure.,Oak Ridge Institute for Science and Education (ORISE), NHEERL, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711.,Integrated Laboratory Systems, Morrisville, North Carolina
| | - Jaleh Abedini
- Center for Computational Toxicology and Exposure.,Integrated Laboratory Systems, Morrisville, NC
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29
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The Connection of Azole Fungicides with Xeno-Sensing Nuclear Receptors, Drug Metabolism and Hepatotoxicity. Cells 2020; 9:cells9051192. [PMID: 32403288 PMCID: PMC7290820 DOI: 10.3390/cells9051192] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/21/2022] Open
Abstract
Azole fungicides, especially triazole compounds, are widely used in agriculture and as pharmaceuticals. For a considerable number of agricultural azole fungicides, the liver has been identified as the main target organ of toxicity. A number of previous studies points towards an important role of nuclear receptors such as the constitutive androstane receptor (CAR), the pregnane-X-receptor (PXR), or the aryl hydrocarbon receptor (AHR), within the molecular pathways leading to hepatotoxicity of these compounds. Nuclear receptor-mediated hepatic effects may comprise rather adaptive changes such as the induction of drug-metabolizing enzymes, to hepatocellular hypertrophy, histopathologically detectable fatty acid changes, proliferation of hepatocytes, and the promotion of liver tumors. Here, we present a comprehensive review of the current knowledge of the interaction of major agricultural azole-class fungicides with the three nuclear receptors CAR, PXR, and AHR in vivo and in vitro. Nuclear receptor activation profiles of the azoles are presented and related to histopathological findings from classic toxicity studies. Important issues such as species differences and multi-receptor agonism and the consequences for data interpretation and risk assessment are discussed.
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30
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Chappell GA, Thompson CM, Wolf JC, Cullen JM, Klaunig JE, Haws LC. Assessment of the Mode of Action Underlying the Effects of GenX in Mouse Liver and Implications for Assessing Human Health Risks. Toxicol Pathol 2020; 48:494-508. [PMID: 32138627 PMCID: PMC7153225 DOI: 10.1177/0192623320905803] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
GenX is an alternative to environmentally persistent long-chain perfluoroalkyl and polyfluoroalkyl substances. Mice exposed to GenX exhibit liver hypertrophy, elevated peroxisomal enzyme activity, and other apical endpoints consistent with peroxisome proliferators. To investigate the potential role of peroxisome proliferator-activated receptor alpha (PPARα) activation in mice, and other molecular signals potentially related to observed liver changes, RNA sequencing was conducted on paraffin-embedded liver sections from a 90-day subchronic toxicity study of GenX conducted in mice. Differentially expressed genes were identified for each treatment group, and gene set enrichment analysis was conducted using gene sets that represent biological processes and known canonical pathways. Peroxisome signaling and fatty acid metabolism were among the most significantly enriched gene sets in both sexes at 0.5 and 5 mg/kg GenX; no pathways were enriched at 0.1 mg/kg. Gene sets specific to the PPARα subtype were significantly enriched. These findings were phenotypically anchored to histopathological changes in the same tissue blocks: hypertrophy, mitoses, and apoptosis. In vitro PPARα transactivation assays indicated that GenX activates mouse PPARα. These results indicate that the liver changes observed in GenX-treated mice occur via a mode of action (MOA) involving PPARα, an important finding for human health risk assessment as this MOA has limited relevance to humans.
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Affiliation(s)
| | | | | | - John M. Cullen
- North Carolina State University College of Veterinary Medicine, Raleigh, NC, USA
| | - James E. Klaunig
- Indiana University, School of Public Health, Bloomington, IN, USA
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31
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Rooney JP, Oshida K, Kumar R, Baldwin WS, Corton JC. Chemical Activation of the Constitutive Androstane Receptor Leads to Activation of Oxidant-Induced Nrf2. Toxicol Sci 2019; 167:172-189. [PMID: 30203046 DOI: 10.1093/toxsci/kfy231] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Exposure to environmentally relevant chemicals that activate the xenobiotic receptors aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), and peroxisome proliferator-activated receptor alpha (PPARα) in rodent test systems often leads to increases in oxidative stress (OS) that contributes to liver cancer induction. We hypothesized that activation of the oxidant-induced transcription factor Nrf2 could be used as a surrogate endpoint for increases in OS. We examined the relationships between activation of xenobiotic receptors and Nrf2 using previously characterized gene expression biomarkers that accurately predict modulation. Using a correlation approach (Running Fisher Test), the biomarkers were compared with microarray profiles in a mouse liver gene expression compendium. Out of the 163 chemicals examined, 47% from 53 studies activated Nrf2. We found consistent coupling between CAR and Nrf2 activation. Out of the 41 chemicals from 32 studies that activated CAR, 90% also activated Nrf2. CAR was activated earlier and at lower doses than Nrf2, indicating CAR activation preceded Nrf2 activation. Nrf2 activation by 2 CAR activators was abolished in CAR-null mice. We hypothesized that Nrf2 is activated by reactive oxygen species from the increased activity of enzymes encoded by Cyp2b family members. However, Nrf2 was similarly activated in the livers of both TCPOBOP-treated wild-type and Cyp2b9/10/13-null mice. This study provides evidence that Nrf2 activation (1) often occurs after exposure to xenobiotic chemicals, (2) is tightly linked to activation of CAR, and (3) does not require induction of 3 Cyp2b genes secondary to CAR activation.
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Affiliation(s)
- John P Rooney
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711.,Oak Ridge Institute for Science and Education (ORISE) participant at the National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Keiyu Oshida
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711.,Toray Industries, Inc, Kanagawa, Japan
| | - Ramiya Kumar
- Environmental Toxicology Program and Biological Sciences Department, Clemson University, Clemson, South Carolina 29634
| | - William S Baldwin
- Environmental Toxicology Program and Biological Sciences Department, Clemson University, Clemson, South Carolina 29634
| | - J Christopher Corton
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
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32
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Krewski D, Andersen ME, Tyshenko MG, Krishnan K, Hartung T, Boekelheide K, Wambaugh JF, Jones D, Whelan M, Thomas R, Yauk C, Barton-Maclaren T, Cote I. Toxicity testing in the 21st century: progress in the past decade and future perspectives. Arch Toxicol 2019; 94:1-58. [DOI: 10.1007/s00204-019-02613-4] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 11/05/2019] [Indexed: 12/19/2022]
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33
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Christopher Corton J. Integrating gene expression biomarker predictions into networks of adverse outcome pathways. CURRENT OPINION IN TOXICOLOGY 2019. [DOI: 10.1016/j.cotox.2019.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Baldwin WS. Phase 0 of the Xenobiotic Response: Nuclear Receptors and Other Transcription Factors as a First Step in Protection from Xenobiotics. NUCLEAR RECEPTOR RESEARCH 2019; 6:101447. [PMID: 31815118 PMCID: PMC6897393 DOI: 10.32527/2019/101447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
This mini-review examines the crucial importance of transcription factors as a first line of defense in the detoxication of xenobiotics. Key transcription factors that recognize xenobiotics or xenobiotic-induced stress such as reactive oxygen species (ROS), include AhR, PXR, CAR, MTF, Nrf2, NF-κB, and AP-1. These transcription factors constitute a significant portion of the pathways induced by toxicants as they regulate phase I-III detoxication enzymes and transporters as well as other protective proteins such as heat shock proteins, chaperones, and anti-oxidants. Because they are often the first line of defense and induce phase I-III metabolism, could these transcription factors be considered the phase 0 of xenobiotic response?
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Affiliation(s)
- William S Baldwin
- Clemson University, Biological Sciences/Environmental Toxicology, 132 Long Hall, Clemson, SC 29634
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Rooney JP, Chorley B, Kleinstreuer N, Corton JC. Identification of Androgen Receptor Modulators in a Prostate Cancer Cell Line Microarray Compendium. Toxicol Sci 2019; 166:146-162. [PMID: 30085300 DOI: 10.1093/toxsci/kfy187] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
High-throughput transcriptomic (HTTr) technologies are increasingly being used to screen environmental chemicals in vitro to identify molecular targets and provide mechanistic context for regulatory testing. Here, we describe the development and validation of a novel gene expression biomarker to identify androgen receptor (AR)-modulating chemicals using a pattern matching method. Androgen receptor biomarker genes were identified by their consistent expression after exposure to 4 AR agonists and 4 AR antagonists and included only those genes that were regulated by AR. The 51 gene biomarker was evaluated as a predictive tool using the fold-change, rank-based Running Fisher algorithm. Using 158 comparisons from cells treated with 95 chemicals, the biomarker gave balanced accuracies for prediction of AR activation or AR suppression of 97% or 98%, respectively. The biomarker correctly classified 16 out of the 17 AR reference antagonists including those that are "weak" and "very weak". Predictions based on microarray profiles from AR-positive LAPC-4 cells treated with 28 chemicals in antagonist mode were compared with those from an AR pathway model which used 11 in vitro HT assays. The balanced accuracy for suppression was 93%. Using our approach, we identified conditions in which AR was modulated in a large collection of microarray profiles from prostate cancer cell lines including (1) constitutively active mutants or knockdown of AR, (2) decreases in availability of androgens by castration or removal from media, and (3) exposure to chemical modulators that work through indirect mechanisms including suppression of AR expression. These results demonstrate that the AR gene expression biomarker could be a useful tool in HTTr to identify AR modulators.
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Affiliation(s)
- John P Rooney
- Oak Ridge Institute for Science and Education (ORISE), Research Triangle Park, North Carolina 27711.,Integrated Systems Toxicology Division, US-EPA, Research Triangle Park, North Carolina 27711
| | - Brian Chorley
- Integrated Systems Toxicology Division, US-EPA, Research Triangle Park, North Carolina 27711
| | - Nicole Kleinstreuer
- NTP Interagency Center for the Evaluation of Alternative Toxicological Methods, NTP, NIEHS, NIH, DHHS, Research Triangle Park, North Carolina
| | - J Christopher Corton
- Integrated Systems Toxicology Division, US-EPA, Research Triangle Park, North Carolina 27711
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Corton JC, Kleinstreuer NC, Judson RS. Identification of potential endocrine disrupting chemicals using gene expression biomarkers. Toxicol Appl Pharmacol 2019; 380:114683. [DOI: 10.1016/j.taap.2019.114683] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 07/05/2019] [Accepted: 07/15/2019] [Indexed: 02/07/2023]
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Corton JC, Witt KL, Yauk CL. Identification of p53 Activators in a Human Microarray Compendium. Chem Res Toxicol 2019; 32:1748-1759. [PMID: 31397557 DOI: 10.1021/acs.chemrestox.9b00052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Biomarkers predictive of molecular and toxicological effects are needed to interpret emerging high-throughput transcriptomic data streams. The previously characterized 63 gene TGx-DDI biomarker that includes 20 genes known to be regulated by p53 was previously shown to accurately predict DNA damage in chemically treated cells. We comprehensively evaluated whether the molecular basis of the DDI predictions was based on a p53-dependent response. The biomarker was compared to microarray data in a compendium derived from human cells using the Running Fisher test, a nonparametric correlation test. Using the biomarker, we identified conditions that led to p53 activation, including exposure to the chemical nutlin-3 which disrupts interactions between p53 and the negative regulator MDM2 or by knockdown of MDM2. The expression of most of the genes in the biomarker (75%) were found to depend on p53 activation status based on gene behavior after TP53 overexpression or knockdown. The biomarker identified DDI chemicals that were strong inducers of p53 in wild-type cells; these p53 responses were decreased or abolished in cells after p53 knockdown by siRNAs. Using the biomarker, we screened ∼1950 chemicals in ∼9800 human cell line chemical vs control comparisons and identified ∼100 chemicals that caused p53 activation. Among the positive chemicals were many that are known to activate p53 through direct and indirect DNA damaging mechanisms. These results contribute to the evidence that the TGx-DDI biomarker is useful for identifying chemicals that cause DDI and activate p53.
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Affiliation(s)
- J Christopher Corton
- Integrated Systems Toxicology Division, NHEERL , United States Environmental Protection Agency , Research Triangle Park, Durham , North Carolina 27711 , United States
| | - Kristine L Witt
- Division of the National Toxicology Program , National Institute of Environmental Health Sciences , Research Triangle Park, Durham , North Carolina 27709 , United States
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Health Canada , Ottawa , Ontario K1A 0K9 , Canada
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Rampersaud A, Lodato NJ, Shin A, Waxman DJ. Widespread epigenetic changes to the enhancer landscape of mouse liver induced by a specific xenobiotic agonist ligand of the nuclear receptor CAR. Toxicol Sci 2019; 171:315-338. [PMID: 31236583 PMCID: PMC6760311 DOI: 10.1093/toxsci/kfz148] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/13/2019] [Accepted: 06/17/2019] [Indexed: 12/13/2022] Open
Abstract
CAR (Nr1i3), a liver nuclear receptor and xenobiotic sensor, induces drug, steroid and lipid metabolism and dysregulates genes linked to hepatocellular carcinogenesis, but its impact on the liver epigenome is poorly understood. TCPOBOP, a halogenated xenochemical and highly specific CAR agonist ligand, induces localized chromatin opening or closing at several thousand mouse liver genomic regions, discovered as differential DNase-hypersensitive sites (ΔDHS). Active enhancer and promoter histone marks induced by TCPOBOP were enriched at opening DHS and TCPOBOP-inducible genes. Enrichment of CAR binding and CAR motifs was seen at opening DHS and their inducible drug/lipid metabolism gene targets, and at many constitutively open DHS located nearby. TCPOBOP-responsive cell cycle and DNA replication genes co-dependent on MET/EGFR signaling for induction were also enriched for CAR binding. A subset of opening DHS and many closing DHS mapping to TCPOBOP-responsive target genes did not bind CAR, indicating an indirect mechanism for their changes in chromatin accessibility. TCPOBOP-responsive DHS were also enriched for induced binding of RXRA, CEBPA and CEBPB, and for motifs for liver-enriched factors that may contribute to liver-specific transcriptional responses to TCPOBOP exposure. These studies elucidate the enhancer landscape of TCPOBOP-exposed liver and the widespread epigenetic changes that are induced by both direct and indirect mechanisms linked to CAR activation. The global maps of thousands of environmental chemical-induced epigenetic changes described here constitute a rich resource for further research on xenochemical effects on liver chromatin states and the epigenome.
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Affiliation(s)
- Andy Rampersaud
- Department of Biology and Bioinformatics Program, Boston University, Boston, MA USA
| | - Nicholas J Lodato
- Department of Biology and Bioinformatics Program, Boston University, Boston, MA USA
| | - Aram Shin
- Department of Biology and Bioinformatics Program, Boston University, Boston, MA USA
| | - David J Waxman
- Department of Biology and Bioinformatics Program, Boston University, Boston, MA USA
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Harrill J, Shah I, Setzer RW, Haggard D, Auerbach S, Judson R, Thomas RS. Considerations for Strategic Use of High-Throughput Transcriptomics Chemical Screening Data in Regulatory Decisions. CURRENT OPINION IN TOXICOLOGY 2019; 15:64-75. [PMID: 31501805 DOI: 10.1016/j.cotox.2019.05.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recently, numerous organizations, including governmental regulatory agencies in the U.S. and abroad, have proposed using data from New Approach Methodologies (NAMs) for augmenting and increasing the pace of chemical assessments. NAMs are broadly defined as any technology, methodology, approach or combination thereof that can be used to provide information on chemical hazard and risk assessment that avoids the use of intact animals. High-throughput transcriptomics (HTTr) is a type of NAM that uses gene expression profiling as an endpoint for rapidly evaluating the effects of large numbers of chemicals on in vitro cell culture systems. As compared to targeted high-throughput screening (HTS) approaches that measure the effect of chemical X on target Y, HTTr is a non-targeted approach that allows researchers to more broadly characterize the integrated response of an intact biological system to chemicals that may affect a specific biological target or many biological targets under a defined set of treatment conditions (time, concentration, etc.). HTTr screening performed in concentration-response mode can provide potency estimates for the concentrations of chemicals that produce perturbations in cellular response pathways. Here, we discuss study design considerations for HTTr concentration-response screening and present a framework for the use of HTTr-based biological pathway-altering concentrations (BPACs) in a screening-level, risk-based chemical prioritization approach. The framework involves concentration-response modeling of HTTr data, mapping gene level responses to biological pathways, determination of BPACs, in vitro-to-in vivo extrapolation (IVIVE) and comparison to human exposure predictions.
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Affiliation(s)
- Joshua Harrill
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Imran Shah
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - R Woodrow Setzer
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Derik Haggard
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | - Scott Auerbach
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, NC, USA
| | - Richard Judson
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Russell S Thomas
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
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Heintz MM, Kumar R, Rutledge MM, Baldwin WS. Cyp2b-null male mice are susceptible to diet-induced obesity and perturbations in lipid homeostasis. J Nutr Biochem 2019; 70:125-137. [PMID: 31202118 DOI: 10.1016/j.jnutbio.2019.05.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 04/26/2019] [Accepted: 05/08/2019] [Indexed: 12/12/2022]
Abstract
Obesity is an endemic problem in the United States and elsewhere, and data indicate that in addition to overconsumption, exposure to specific chemicals enhances obesity. CYP2B metabolizes multiple endo- and xenobiotics, and recent data suggests that repression of Cyp2b activity increases dyslipidemia and age-onset obesity, especially in males. To investigate the role played by Cyp2b in lipid homeostasis and obesity, we treated wildtype and Cyp2b-null mice with a normal (ND) or 60% high-fat diet (HFD) for 10 weeks and determined metabolic and molecular changes. Male HFD-fed Cyp2b-null mice weigh 15% more than HFD-fed wildtype mice, primarily due to an increase in white adipose tissue (WAT); however, Cyp2b-null female mice did not demonstrate greater body mass or WAT. Serum parameters indicate increased ketosis, leptin and cholesterol in HFD-fed Cyp2b-null male mice compared to HFD-fed wildtype mice. Liver triglycerides and liver:serum triglyceride ratios were higher than their similarly treated wildtype counterparts in Cyp2b-null male mice, indicating a role for Cyp2b in fatty acid metabolism regardless of diet. Furthermore, RNAseq demonstrates that hepatic gene expression in ND-fed Cyp2b-null male mice is similar to HFD-fed WT male mice, suggestive of fatty liver disease progression and a role for Cyp2b in lipid homeostasis. Females did not show as demonstrative changes in liver health, and significantly fewer changes in gene expression, as well as gene expression associated with liver disease. Overall our data indicates that the repression or inhibition of CYP2B may exacerbate metabolic disorders and cause obesity by perturbing fatty acid metabolism, especially in males.
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Affiliation(s)
- Melissa M Heintz
- Environmental Toxicology Program, Clemson University, Clemson, SC 29634
| | - Ramiya Kumar
- Biological Sciences, Clemson University, Clemson, SC 29634
| | | | - William S Baldwin
- Environmental Toxicology Program, Clemson University, Clemson, SC 29634; Biological Sciences, Clemson University, Clemson, SC 29634.
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41
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Corton JC. Frequent Modulation of the Sterol Regulatory Element Binding Protein (SREBP) by Chemical Exposure in the Livers of Rats. ACTA ACUST UNITED AC 2019; 10:113-129. [PMID: 30931410 DOI: 10.1016/j.comtox.2019.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Inappropriate activation of sterol regulatory element-binding proteins (SREBPs) can lead to non-alcoholic fatty liver disease (NAFLD). To link chemical exposure to SREBP activity, a previously characterized gene expression biomarker (Rooney et al., 2019) was used to identify microarray comparisons from rat liver that exhibited significant positive or negative correlation to the biomarker. The effects of 620 chemicals on SREBP activity were examined across 9305 chemical-dose-time microarray comparisons. SREBP was found to be frequently modulated by chemical exposure with 54% of the chemicals affecting SREBP activity. Activators included inhibitors of cholesterogenesis that act to inhibit HMG-CoA reductase (statins) or inhibit Cyp51 (conazoles). Most chemical effects were transient, lasting usually no more than 2-4 days. Modulation of SREBP in most cases led to coordinated increases or decreases in lipogenic and cholesterogenic genes. However, 570 chemical exposure conditions were identified in which regulation was uncoupled. Most of these conditions affected cholesterogenic genes in the absence of parallel effects on lipogenic genes. Together, these findings show that SREBP is a frequent target of chemical exposure and expression of lipogenic and cholesterogenic genes can be uncoupled.
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Affiliation(s)
- J Christopher Corton
- Integrated Systems Toxicology Division, NHEERL/ORD, US-EPA, Research Triangle Park, NC 27711
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42
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Peffer RC, Cowie DE, Currie RA, Minnema DJ. Sedaxane-Use of Nuclear Receptor Transactivation Assays, Toxicogenomics, and Toxicokinetics as Part of a Mode of Action Framework for Rodent Liver Tumors. Toxicol Sci 2019; 162:582-598. [PMID: 29244179 DOI: 10.1093/toxsci/kfx281] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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 nonrelevant to human risk assessments. Methods and results in the MOA work for sedaxane illustrate promising directions that future MOA studies may be able to employ, in the spirit of "Tox21" and reduction of in vivo animal use: (1) currently available in vitro CAR and PXR reporter assays demonstrated that sedaxane is a direct CAR activator in mice and rats, and a weak PXR activator in rats; (2) mouse liver microarray results compared with a published CAR biomarker signature (based on 83 genes) showed a clear, statistical match, and a lack of correlation to similar biomarker signatures for AhR, PPARα, and STAT5B; (3) Ki67 immunohistochemistry and zonal image analysis showed significant increases in this marker of cell proliferation in mouse liver, without the need to dose a DNA labeling agent; and (4) toxicokinetic analysis of Cmax levels of sedaxane in blood showed a marked species difference between mice and rats that helps to explain differences in sensitivity to sedaxane. Incorporating these tools into the study plan for a new agrochemical or drug during development offers a promising alternative to the traditional need to conduct later, specialized MOA studies after the results of chronic bioassays are known.
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Affiliation(s)
- Richard C Peffer
- Syngenta Crop Protection, LLC, Greensboro, North Carolina 27419-8300
| | - David E Cowie
- Syngenta Ltd., Jealott's Hill International Research Center, Bracknell, Berkshire RG42 6EY, UK
| | - Richard A Currie
- Syngenta Ltd., Jealott's Hill International Research Center, Bracknell, Berkshire RG42 6EY, UK
| | - Daniel J Minnema
- Syngenta Crop Protection, LLC, Greensboro, North Carolina 27419-8300
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43
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Hardesty JE, Wahlang B, Falkner KC, Shi H, Jin J, Wilkey D, Merchant M, Watson C, Prough RA, Cave MC. Hepatic signalling disruption by pollutant Polychlorinated biphenyls in steatohepatitis. Cell Signal 2019; 53:132-139. [PMID: 30300668 PMCID: PMC6289731 DOI: 10.1016/j.cellsig.2018.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND Polychlorinated biphenyl-mediated steatohepatitis has been shown to be due in part to inhibition of epidermal growth factor receptor (EGFR) signalling. EGFR signalling regulates many facets of hepatocyte function, but it is unclear which other kinases and pathways are involved in the development of toxicant-associated steatohepatitis (TASH). METHODS Comparative hepatic phosphoproteomic analysis was used to identify which kinases were affected by either PCB exposure (Aroclor 1260 mixture), high fat diet (HFD), or their interaction in a chronic exposure model of TASH. Cellular assays and western blot analysis were used to validate the phosphoproteomic findings. RESULTS 1760 unique phosphorylated peptides were identified and of those 588 were significantly different. PCB exposure and dietary interaction promoted a near 25% reduction of hepatic phospho-peptides. Leptin and insulin signalling were pathways highly affected by PCB exposure and liver necrosis was a pathologic ontology over represented due to interaction between PCBs and a HFD. Casein kinase 2 (CK2), Extracellular regulated kinase (ERK), Protein kinase B (AKT), and Cyclin dependent kinase (CDK) activity were demonstrated to be downregulated after PCB exposure and this downregulation was exacerbated with a HFD. PCB exposure led to a loss of hepatic CK2 subunit expression limiting CK2 kinase activity and negatively regulating caspase-3 (CASP3). PCBs promoted secondary necrosis in vitro validating the latter observation. The loss of hepatic phosphoprotein signalling appeared to be due to decreased signal transduction rather than phosphatase upregulation. CONCLUSIONS PCBs are signal disrupting chemicals that promote secondary necrosis through affecting a myriad of liver processes including metabolism and cellular maintenance. PCB exposure, particularly with interaction with a HFD greatly down-regulates the hepatic kinome. More data are needed on signalling disruption and its impact on liver health.
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Affiliation(s)
- Josiah E Hardesty
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Banrida Wahlang
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; University of Louisville Superfund Research Program, University of Louisville, Louisville, KY 40202, USA.
| | - K Cameron Falkner
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; Hepatobiology & Toxicology Center, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Hongxue Shi
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Jian Jin
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Daniel Wilkey
- The Proteomics Core, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Michael Merchant
- The Proteomics Core, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Corey Watson
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Russell A Prough
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Matthew C Cave
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; The Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA; The Jewish Hospital Liver Transplant Program, Louisville, KY 40202, USA; Hepatobiology & Toxicology Center, University of Louisville School of Medicine, Louisville, KY 40202, USA; University of Louisville Alcohol Research Center, University of Louisville, Louisville, KY 40202, USA; University of Louisville Superfund Research Program, University of Louisville, Louisville, KY 40202, USA.
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44
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Corton JC, Williams A, Yauk CL. Using a gene expression biomarker to identify DNA damage-inducing agents in microarray profiles. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:772-784. [PMID: 30329178 PMCID: PMC7875442 DOI: 10.1002/em.22243] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 08/01/2018] [Accepted: 08/07/2018] [Indexed: 05/22/2023]
Abstract
High-throughput transcriptomic technologies are increasingly being used to screen environmental chemicals in vitro to provide mechanistic context for regulatory testing. The TGx-DDI biomarker is a 64-gene expression profile generated from testing 28 model chemicals or treatments (13 that cause DNA damage and 15 that do not) in human TK6 cells. While the biomarker is very accurate at predicting DNA damage inducing (DDI) potential using the nearest shrunken centroid method, the broad utility of the biomarker using other computational methods is not fully known. Here, we determined the accuracy of the biomarker used with the Running Fisher test, a nonparametric correlation test. In TK6 cells, the methods could readily differentiate DDI and non-DDI compounds with balanced accuracies of 87-97%, depending on the threshold for determining DDI positives. The methods identified DDI agents in the metabolically competent hepatocyte cell line HepaRG (accuracy = 90%) but not in HepG2 cells or hepatocytes derived from embryonic stem cells (60 and 80%, respectively). DDI was also accurately classified when the gene expression changes were derived using the nCounter technology (accuracy = 89%). In addition, we found: (1) not all genes contributed equally to the correlations; (2) the minimal overlap in genes between the biomarker and the individual comparisons required for significant positive correlation was 10 genes, but usually was much higher; and (3) different sets of genes in the biomarker can by themselves contribute to the significant correlations. Overall, these results demonstrate the utility of the biomarker to accurately classify DDI agents. Environ. Mol. Mutagen. 59:772-784, 2018. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- J. Christopher Corton
- Integrated Systems Toxicology Division, US-EPA,
Research Triangle Park, NC 27711
- Corresponding author: Chris Corton, Integrated
Systems Toxicology Division, National Health and Environmental Effects Research
Lab, US Environmental Protection Agency, 109 T.W. Alexander Dr., MD-B143-06,
Research Triangle Park, NC 27711, ,
919-541-0092 (office), 919-541-0694 (fax)
| | - Andrew Williams
- Environmental Health Science and Research Bureau,
Health Canada, Ottawa, Ontario, Canada, K1A 0K9
| | - Carole L. Yauk
- Environmental Health Science and Research Bureau,
Health Canada, Ottawa, Ontario, Canada, K1A 0K9
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45
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Copple IM, den Hollander W, Callegaro G, Mutter FE, Maggs JL, Schofield AL, Rainbow L, Fang Y, Sutherland JJ, Ellis EC, Ingelman-Sundberg M, Fenwick SW, Goldring CE, van de Water B, Stevens JL, Park BK. Characterisation of the NRF2 transcriptional network and its response to chemical insult in primary human hepatocytes: implications for prediction of drug-induced liver injury. Arch Toxicol 2018; 93:385-399. [PMID: 30426165 PMCID: PMC6373176 DOI: 10.1007/s00204-018-2354-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/08/2018] [Indexed: 01/05/2023]
Abstract
The transcription factor NRF2, governed by its repressor KEAP1, protects cells against oxidative stress. There is interest in modelling the NRF2 response to improve the prediction of clinical toxicities such as drug-induced liver injury (DILI). However, very little is known about the makeup of the NRF2 transcriptional network and its response to chemical perturbation in primary human hepatocytes (PHH), which are often used as a translational model for investigating DILI. Here, microarray analysis identified 108 transcripts (including several putative novel NRF2-regulated genes) that were both downregulated by siRNA targeting NRF2 and upregulated by siRNA targeting KEAP1 in PHH. Applying weighted gene co-expression network analysis (WGCNA) to transcriptomic data from the Open TG-GATES toxicogenomics repository (representing PHH exposed to 158 compounds) revealed four co-expressed gene sets or ‘modules’ enriched for these and other NRF2-associated genes. By classifying the 158 TG-GATES compounds based on published evidence, and employing the four modules as network perturbation metrics, we found that the activation of NRF2 is a very good indicator of the intrinsic biochemical reactivity of a compound (i.e. its propensity to cause direct chemical stress), with relatively high sensitivity, specificity, accuracy and positive/negative predictive values. We also found that NRF2 activation has lower sensitivity for the prediction of clinical DILI risk, although relatively high specificity and positive predictive values indicate that false positive detection rates are likely to be low in this setting. Underpinned by our comprehensive analysis, activation of the NRF2 network is one of several mechanism-based components that can be incorporated into holistic systems toxicology models to improve mechanistic understanding and preclinical prediction of DILI in man.
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Affiliation(s)
- Ian M Copple
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3GE, UK.
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institute, 171-77, Stockholm, Sweden.
| | - Wouter den Hollander
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Giulia Callegaro
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Fiona E Mutter
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3GE, UK
| | - James L Maggs
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3GE, UK
| | - Amy L Schofield
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3GE, UK
| | - Lucille Rainbow
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Yongxiang Fang
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Jeffrey J Sutherland
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| | - Ewa C Ellis
- Liver Cell Lab, Unit for Transplantation Surgery, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska University Hospital Huddinge, 141-86, Stockholm, Sweden
| | - Magnus Ingelman-Sundberg
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institute, 171-77, Stockholm, Sweden
| | - Stephen W Fenwick
- Department of Hepatobiliary Surgery, Aintree University Hospital NHS Foundation Trust, Liverpool, L9 7AL, UK
| | - Christopher E Goldring
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3GE, UK
| | - Bob van de Water
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC, Leiden, The Netherlands
| | - James L Stevens
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| | - B Kevin Park
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3GE, UK
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Rooney J, Hill T, Qin C, Sistare FD, Corton JC. Adverse outcome pathway-driven identification of rat liver tumorigens in short-term assays. Toxicol Appl Pharmacol 2018; 356:99-113. [DOI: 10.1016/j.taap.2018.07.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/12/2018] [Accepted: 07/20/2018] [Indexed: 02/07/2023]
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Trevisi P, Priori D, Jansman AJM, Luise D, Koopmans SJ, Hynönen U, Palva A, van der Meulen J, Bosi P. Molecular networks affected by neonatal microbial colonization in porcine jejunum, luminally perfused with enterotoxigenic Escherichia coli, F4ac fimbria or Lactobacillus amylovorus. PLoS One 2018; 13:e0202160. [PMID: 30161141 PMCID: PMC6116929 DOI: 10.1371/journal.pone.0202160] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/27/2018] [Indexed: 12/11/2022] Open
Abstract
The development of an early complex gut microbiota may play an important role in the protection against intestinal dysbiosis later in life. The significance of the developed microbiota for gut barrier functionality upon interaction with pathogenic or beneficial bacteria is largely unknown. The transcriptome of differently perfused jejunal loops of 12 caesarian-derived pigs, neonatally associated with microbiota of different complexity, was studied. Piglets received pasteurized sow colostrum at birth (d0), a starter microbiota (Lactobacillus amylovorus (LAM), Clostridium glycolicum, and Parabacteroides) on d1-d3, and a placebo inoculant (simple association, SA) or an inoculant consisting of sow’s diluted feces (complex association, CA) on d3-d4. On d 26–37, jejunal loops were perfused for 8 h with either enterotoxigenic Escherichia coli F4 (ETEC), purified F4 fimbriae, LAM or saline control (CTRL). Gene expression of each intestinal loop was analyzed by Affymetrix Porcine Gene 1.1_ST array strips. Gene Set Enrichment Analysis was performed on expression values. Compared to CTRL, 184 and 74; 2 and 139; 2 and 48 gene sets, were up- and down-regulated by ETEC, F4 and LAM, respectively. ETEC up-regulated networks related to inflammatory and immune responses, RNA processing, and mitosis. There was a limited overlap in up-regulated gene sets between ETEC and F4 fimbriae. LAM down-regulated genes related to inflammatory and immune responses, as well as to cellular compound metabolism. In CA pigs, 57 gene sets were up-regulated by CA, while 73 were down-regulated compared to SA. CA up-regulated gene sets related to lymphocyte modulation and to cellular defense in all loop perfusions. In CA pigs, compared to SA pigs, genes for chemokine and cytokine activity and for response to external stimuli were down-regulated in ETEC-perfused loops and up-regulated in CTRL. The results highlight the importance of the nature of neonatal microbial colonization in the response to microbial stimuli later in life.
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Affiliation(s)
| | | | | | - Diana Luise
- DISTAL, University of Bologna, Bologna, Italy
| | | | - Ulla Hynönen
- Department of Veterinary Biosciences, Division of Microbiology and Epidemiology, University of Helsinki, Helsinki, Finland
| | - Airi Palva
- Department of Veterinary Biosciences, Division of Microbiology and Epidemiology, University of Helsinki, Helsinki, Finland
| | | | - Paolo Bosi
- DISTAL, University of Bologna, Bologna, Italy
- * E-mail:
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48
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Braeuning A, Kollotzek F, Zeller E, Knorpp T, Templin MF, Schwarz M. Mouse Hepatomas with Ha-ras and B-raf Mutations Differ in Mitogen-Activated Protein Kinase Signaling and Response to Constitutive Androstane Receptor Activation. Drug Metab Dispos 2018; 46:1462-1465. [PMID: 30115646 DOI: 10.1124/dmd.118.083014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/14/2018] [Indexed: 12/31/2022] Open
Abstract
Nuclear receptors mediate the hepatic induction of drug-metabolizing enzymes by xenobiotics. Not much is known about enzyme induction in liver tumors. Here, we treated tumor-bearing mice with phenobarbital, an activator of the constitutive androstane receptor (CAR), to analyze the response of chemically induced Ha-ras- and B-raf-mutated mouse liver adenoma to CAR activation in vivo. Both tumor subpopulations possess almost identical gene expression profiles. CAR target gene induction in the tumors was studied at the mRNA and protein levels, and a reverse-phase protein microarray approach was chosen to characterize important signaling cascades. CAR target gene induction was pronounced in B-raf-mutated but not in Ha-ras-mutated tumors. Phosphoproteomic profiling revealed that phosphorylation-activated extracellular signal-regulated kinase (ERK) 1/2 was more abundant in Ha-ras-mutated than in B-raf-mutated tumors. ERK activation in tumor tissue was negatively correlated with CAR target induction. ERK activation is known to inhibit CAR-dependent transcription. In summary, profound differences exist between the two closely related tumor subpopulations with respect to the activation of mitogenic signaling cascades, and these dissimilarities might explain the differences in xenobiotic induction of CAR target genes.
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Affiliation(s)
- Albert Braeuning
- Department of Toxicology, University of Tübingen, Tübingen, Germany (A.B., F.K., E.Z., M.S.); Natural and Medical Sciences Institute, Reutlingen, Germany (T.K., M.F.T.); and Department Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany (A.B.)
| | - Ferdinand Kollotzek
- Department of Toxicology, University of Tübingen, Tübingen, Germany (A.B., F.K., E.Z., M.S.); Natural and Medical Sciences Institute, Reutlingen, Germany (T.K., M.F.T.); and Department Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany (A.B.)
| | - Eva Zeller
- Department of Toxicology, University of Tübingen, Tübingen, Germany (A.B., F.K., E.Z., M.S.); Natural and Medical Sciences Institute, Reutlingen, Germany (T.K., M.F.T.); and Department Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany (A.B.)
| | - Thomas Knorpp
- Department of Toxicology, University of Tübingen, Tübingen, Germany (A.B., F.K., E.Z., M.S.); Natural and Medical Sciences Institute, Reutlingen, Germany (T.K., M.F.T.); and Department Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany (A.B.)
| | - Markus F Templin
- Department of Toxicology, University of Tübingen, Tübingen, Germany (A.B., F.K., E.Z., M.S.); Natural and Medical Sciences Institute, Reutlingen, Germany (T.K., M.F.T.); and Department Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany (A.B.)
| | - Michael Schwarz
- Department of Toxicology, University of Tübingen, Tübingen, Germany (A.B., F.K., E.Z., M.S.); Natural and Medical Sciences Institute, Reutlingen, Germany (T.K., M.F.T.); and Department Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany (A.B.)
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49
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Rooney J, Oshida K, Vasani N, Vallanat B, Ryan N, Chorley BN, Wang X, Bell DA, Wu KC, Aleksunes LM, Klaassen CD, Kensler TW, Corton JC. Activation of Nrf2 in the liver is associated with stress resistance mediated by suppression of the growth hormone-regulated STAT5b transcription factor. PLoS One 2018; 13:e0200004. [PMID: 30114225 PMCID: PMC6095522 DOI: 10.1371/journal.pone.0200004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/15/2018] [Indexed: 12/30/2022] Open
Abstract
The transcription factor Nrf2 (encoded by Nfe2l2) induces expression of numerous detoxifying and antioxidant genes in response to oxidative stress. The cytoplasmic protein Keap1 interacts with and represses Nrf2 function. Computational approaches were developed to identify factors that modulate Nrf2 in a mouse liver gene expression compendium. Forty-eight Nrf2 biomarker genes were identified using profiles from the livers of mice in which Nrf2 was activated genetically in Keap1-null mice or chemically by a potent activator of Nrf2 signaling. The rank-based Running Fisher statistical test was used to determine the correlation between the Nrf2 biomarker genes and a test set of 81 profiles with known Nrf2 activation status demonstrating a balanced accuracy of 96%. For a large number of factors examined in the compendium, we found consistent relationships between activation of Nrf2 and feminization of the liver transcriptome through suppression of the male-specific growth hormone (GH)-regulated transcription factor STAT5b. The livers of female mice exhibited higher Nrf2 activation than male mice in untreated or chemical-treated conditions. In male mice, Nrf2 was activated by treatment with ethinyl estradiol, whereas in female mice, Nrf2 was suppressed by treatment with testosterone. Nrf2 was activated in 5 models of disrupted GH signaling containing mutations in Pit1, Prop1, Ghrh, Ghrhr, and Ghr. Out of 59 chemical treatments that activated Nrf2, 36 exhibited STAT5b suppression in the male liver. The Nrf2-STAT5b coupling was absent in in vitro comparisons of chemical treatments. Treatment of male and female mice with 11 chemicals that induce oxidative stress led to activation of Nrf2 to greater extents in females than males. The enhanced basal and inducible levels of Nrf2 activation in females relative to males provides a molecular explanation for the greater resistance often seen in females vs. males to age-dependent diseases and chemical-induced toxicity.
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Affiliation(s)
- John Rooney
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Keiyu Oshida
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Naresh Vasani
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Beena Vallanat
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Natalia Ryan
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Brian N. Chorley
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Xuting Wang
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States of America
| | - Douglas A. Bell
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States of America
| | - Kai C. Wu
- University of Kansas Medical Center, Kansas City, KS, United States of America
| | - Lauren M. Aleksunes
- Rutgers University, Ernest Mario School of Pharmacy, Department of Pharmacology and Toxicology, Piscataway, NJ, United States of America
| | | | - Thomas W. Kensler
- Department of Pharmacology & Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Environmental Health & Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
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Yamada T. Case examples of an evaluation of the human relevance of the pyrethroids/pyrethrins-induced liver tumours in rodents based on the mode of action. Toxicol Res (Camb) 2018; 7:681-696. [PMID: 30090614 PMCID: PMC6062351 DOI: 10.1039/c7tx00288b] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/10/2018] [Indexed: 01/01/2023] Open
Abstract
Rodent carcinogenicity studies are useful for screening for human carcinogens but they are not perfect. Some modes of action (MOAs) lead to cancers in both experimental rodents and humans, but others that lead to cancers in rodents do not do so in humans. Therefore, analysing the MOAs by which chemicals produce tumours in rodents and determining the relevance of such tumour data for human risk are critical. Recently, experimental data were obtained as case examples of an evaluation of the human relevance of pyrethroid (metofluthrin and momfluorothrin)- and pyrethrins-induced liver tumours in rats based on MOA. The MOA analysis, based on the International Programme on Chemical Safety (IPCS) framework, concluded that experimental data strongly support that the postulated MOA for metofluthrin-, momfluorothrin- and pyrethrins-produced rat hepatocellular tumours is mediated by constitutive androstane receptor (CAR) activation. Since metofluthrin and momfluorothrin are close structural analogues, reproducible outcomes for both chemicals provide confidence in the MOA findings. Furthermore, cultured human hepatocyte studies and humanized chimeric mouse liver studies demonstrated species difference between human hepatocytes (refractory to the mitogenic effects of these compounds) and rat hepatocytes (sensitive to their mitogenic effects). These data strongly support the hypothesis that the CAR-mediated MOA for liver tumorigenesis is of low carcinogenic risk for humans. In this research, in addition to cultured human hepatocyte studies, the usefulness of the humanized chimeric liver mouse models was clearly demonstrated. These data substantially influenced decisions in regulatory toxicology. In this review I comprehensively discuss the human relevance of the CAR-mediated MOA for rodent liver tumorigenesis based on published information, including our recent molecular research on CAR-mediated MOA.
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Affiliation(s)
- Tomoya Yamada
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
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