1
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Vujic E, Ferguson SS, Brouwer KLR. Effects of PFAS on human liver transporters: implications for health outcomes. Toxicol Sci 2024; 200:213-227. [PMID: 38724241 DOI: 10.1093/toxsci/kfae061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024] Open
Abstract
Per- and polyfluoroalkyl substances (PFAS) have become internationally recognized over the past three decades as persistent organic pollutants used in the production of various consumer and industrial goods. Research efforts continue to gauge the risk that historically used, and newly produced, PFAS may cause to human health. Numerous studies report toxic effects of PFAS on the human liver as well as increased serum cholesterol levels in adults. A major concern with PFAS, also dubbed "forever chemicals," is that they accumulate in the liver and kidney and persist in serum. The mechanisms responsible for their disposition and excretion in humans are poorly understood. A better understanding of the interaction of PFAS with liver transporters, as it pertains to the disposition of PFAS and other xenobiotics, could provide mechanistic insight into human health effects and guide efforts toward risk assessment of compounds in development. This review summarizes the current state of the literature on the emerging relationships (eg, substrates, inhibitors, modulators of gene expression) between PFAS and specific hepatic transporters. The adaptive and toxicological responses of hepatocytes to PFAS that reveal linkages to pathologies and epidemiological findings are highlighted. The evidence suggests that our understanding of the molecular landscape of PFAS must improve to determine their impact on the expression and function of hepatocyte transporters that play a key role in PFAS or other xenobiotic disposition. From here, we can assess what role these changes may have in documented human health outcomes.
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Affiliation(s)
- Ena Vujic
- Curriculum in Toxicology & Environmental Medicine, School of Medicine, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Stephen S Ferguson
- Division of Translational Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Kim L R Brouwer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Curriculum in Toxicology & Environmental Medicine, School of Medicine, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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2
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Sun Y, Zhang L, Jiang Z. The role of peroxisome proliferator-activated receptors in the regulation of bile acid metabolism. Basic Clin Pharmacol Toxicol 2024; 134:315-324. [PMID: 38048777 DOI: 10.1111/bcpt.13971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 11/25/2023] [Accepted: 11/30/2023] [Indexed: 12/06/2023]
Abstract
Bile acids are synthesized from cholesterol in the liver. Dysregulation of bile acid homeostasis, characterized by excessive accumulation in the liver, gallbladder and blood, can lead to hepatocellular damage and the development of cholestatic liver disease. Nuclear receptors play a crucial role in the control of bile acid metabolism by efficiently regulating bile acid synthesis and transport in the liver. Among these receptors, peroxisome proliferator-activated receptor (PPAR), a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily, controls the expression of genes involved in adipogenesis, lipid metabolism, inflammation and glucose homeostasis and has emerged as a potential therapeutic target for the treatment of the metabolic syndrome in the past two decades. Emerging evidence suggests that PPAR activation holds promise as a therapeutic target for cholestatic liver disease, as it affects both bile acid production and transport. This review provides a comprehensive overview of recent advances in elucidating the role of PPAR in the regulation of bile acid metabolism, highlighting the current position of PPAR agonists in the treatment of primary biliary cholangitis. By summarizing the specific regulatory effects of PPAR on bile acids, this review contributes to the exploration of novel therapeutic strategies for cholestatic liver diseases.
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Affiliation(s)
- Yuqing Sun
- New Drug Screening Center, Jiangsu Center for Pharmacodynamics Research and Evaluation, Pharmaceutical Animal Experimental Center, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Luyong Zhang
- New Drug Screening Center, Jiangsu Center for Pharmacodynamics Research and Evaluation, Pharmaceutical Animal Experimental Center, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
- Center for Drug Research and Development, Guangdong Pharmaceutical University, Guangzhou, China
| | - Zhenzhou Jiang
- New Drug Screening Center, Jiangsu Center for Pharmacodynamics Research and Evaluation, Pharmaceutical Animal Experimental Center, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing, China
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3
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Yu X, Zhang Y, Cogliati B, Klaassen CD, Kumar S, Cheng X, Bu P. Distinct bile acid alterations in response to a single administration of PFOA and PFDA in mice. Toxicology 2024; 502:153719. [PMID: 38181850 PMCID: PMC10922993 DOI: 10.1016/j.tox.2023.153719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/22/2023] [Accepted: 12/30/2023] [Indexed: 01/07/2024]
Abstract
Per- and polyfluoroalkyl substances (PFASs), a group of synthetic chemicals that were once widely used for industrial purposes and in consumer products, are widely found in the environment and in human blood due to their extraordinary resistance to degradation. Once inside the body, PFASs can activate nuclear receptors such as PPARα and CAR. The present study aimed to investigate the impact of perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) on liver structure and functions, as well as bile acid homeostasis in mice. A single administration of 0.1 mmole/kg of PFDA, not PFOA, elevated serum ALT and bilirubin levels and caused cholestasis in WT mice. PFDA increased total and various bile acid species in serum but decreased them in the liver. Furthermore, in mouse livers, PFDA, not PFOA, down-regulated mRNA expression of uptake transporters (Ntcp, Oatp1a1, 1a4, 1b2, and 2b1) but induced efflux transporters (Bcrp, Mdr2, and Mrp2-4). In addition, PFDA, not PFOA, decreased Cyp7a1, 7b1, 8b1, and 27a1 mRNA expression in mouse livers with concomitant hepatic accumulation of cholesterol. In contrast, in PPARα-null mice, PFDA did not increase serum ALT, bilirubin, or total bile acids, but produced prominent hepatosteatosis; and the observed PFDA-induced expression changes of transporters and Cyps in WT mice were largely attenuated or abolished. In CAR-null mice, the observed PFDA-induced bile acid alterations in WT mice were mostly sustained. These results indicate that, at the dose employed, PFDA has more negative effects than PFOA on liver function. PPARα appears to play a major role in mediating most of PFDA-induced effects, which were absent or attenuated in PPARα-null mice. Lack of PPARα, however, exacerbated hepatic steatosis. Our findings indicate separated roles of PPARα in mediating the adaptive responses to PFDA: protective against hepatosteatosis but exacerbating cholestasis.
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Affiliation(s)
- Xiaoxiao Yu
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Jamaica, NY 11439, United States
| | - Youcai Zhang
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, PR China
| | - Bruno Cogliati
- Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave., New York, NY 10029, United States; Department of Pathology, School of Veterinary Medicine and Animal Science, University of Sao Paulo, 05508-270, Sao Paulo, Brazil
| | - Curtis D Klaassen
- University of Kansas Medical Center, Kansas City, KS 66103, United States
| | - Sanaya Kumar
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Jamaica, NY 11439, United States
| | - Xingguo Cheng
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Jamaica, NY 11439, United States
| | - Pengli Bu
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Jamaica, NY 11439, United States.
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Yang L, Chen Y, Ji H, Zhang X, Zhou Y, Li J, Wang Y, Xie Z, Yuan W, Liang H, Miao M. Per- and Poly-fluoroalkyl Substances and Bile Acid Profiles in Pregnant Women. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15869-15881. [PMID: 37821457 DOI: 10.1021/acs.est.3c05106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Alterations in bile acid (BA) profiles are closely associated with adverse outcomes in pregnant women and their offspring and may be one potential pathway underlying the related metabolic effects of per- and poly-fluoroalkyl substances (PFAS) exposure. However, evidence of associations between PFAS exposure and BA profiles in pregnant women is scarce. This study examined the associations of individual PFAS and PFAS mixture with BA profiles of pregnant women. We obtained quantitative data on the plasma concentrations of 13 PFAS and 15 BAs in 645 pregnant women from the Jiashan birth cohort. In Bayesian kernel machine regression models, the PFAS mixture was associated with increased plasma CA, TCA, TCDCA, and GLCA levels but with decreased GCA and LCA concentrations. Furthermore, the PFAS mixture was associated with increased concentrations of total BAs and the secondary/primary BA ratio but with decreased conjugated/unconjugated and glycine/taurine-conjugated BA ratios. PFHxS, PFUdA, PFOS, PFNA, and PFDA were the dominant contributors. The results of the linear regression analysis of individual PFAS were generally similar. Our findings provide the first epidemiological evidence for the associations of a PFAS mixture with BA profiles in pregnant women and may provide explanatory insights into the biological pathways underlying the related metabolic effects of PFAS exposure.
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Affiliation(s)
- Lan Yang
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Public Health, Fudan University, Shanghai 200237, China
| | - Yao Chen
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Public Health, Fudan University, Shanghai 200237, China
| | - Honglei Ji
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Public Health, Fudan University, Shanghai 200237, China
| | - Xi Zhang
- Clinical Research Unit, Xinhua Hospital Affiliated to Shanghai Jiao Tong University, School of Medicine, Shanghai 200092, China
| | - Yan Zhou
- Hubei Provincial Key Laboratory of Applied Toxicology, National Reference Laboratory of Dioxin, Hubei Provincial Center for Disease Control and Prevention, Wuhan 430079, China
| | - Jianhui Li
- Shanghai Institute for Biomedical and Pharmaceutical Technologies, Hospital of SIPPR, Shanghai 200032, China
| | - Yan Wang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhenzhen Xie
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Public Health, Fudan University, Shanghai 200237, China
| | - Wei Yuan
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Public Health, Fudan University, Shanghai 200237, China
| | - Hong Liang
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Public Health, Fudan University, Shanghai 200237, China
| | - Maohua Miao
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, School of Public Health, Fudan University, Shanghai 200237, China
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5
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Gao B, Chen L, Xu W, Shan J, Shen W, Gao N. Effects of Perfluorooctanoic Acid on Gut Microbiota and Microbial Metabolites in C57BL/6J Mice. Metabolites 2023; 13:707. [PMID: 37367865 DOI: 10.3390/metabo13060707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/22/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023] Open
Abstract
Perfluorooctanoic acid (PFOA) represents an increasing public health concern due to its persistence in the environment and its toxic effects. The gut microbiota is known to produce various metabolites that assist the host to maintain metabolic homeostasis. However, few studies have explored the effects of PFOA on gut-microbiota-related metabolites. In the present study, male C57BL/6J mice were exposed to 1 ppm of PFOA in drinking water for four weeks and integrative analysis of the gut microbiome and metabolome was performed to reveal the health effects of PFOA. Our results showed that PFOA disturbed both the gut microbiota composition and the metabolic profiles of the feces, serum, and liver in mice. A correlation was found between Lachnospiraceae UCG004, Turicibacter, Ruminococcaceae, and different fecal metabolites. Significant alterations of gut-microbiota-related metabolites were induced by PFOA exposure, including bile acids and tryptophan metabolites such as 3-indoleacrylic acid and 3-indoleacetic acid. The findings of this study are helpful to improve the understanding of the health effects of PFOA, which might be mediated through the gut microbiota and its related metabolites.
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Affiliation(s)
- Bei Gao
- School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing 210044, China
- Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Lixia Chen
- School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Weichen Xu
- Medical Metabolomics Center, Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Jinjun Shan
- Medical Metabolomics Center, Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Weishou Shen
- School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative In-novation Center of Atmospheric Environment and Equipment Technology, Nanjing 210044, China
- Institute of Soil Health and Climate-Smart Agriculture, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Nan Gao
- School of Biological and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
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6
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Heintz MM, Haws LC, Klaunig JE, Cullen JM, Thompson CM. Assessment of the mode of action underlying development of liver lesions in mice following oral exposure to HFPO-DA and relevance to humans. Toxicol Sci 2023; 192:15-29. [PMID: 36629480 PMCID: PMC10025879 DOI: 10.1093/toxsci/kfad004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
HFPO-DA (ammonium, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate) is a short-chain polyfluorinated alkyl substance (PFAS) used in the manufacture of some types of fluorinated polymers. Like many PFAS, toxicity studies with HFPO-DA indicate the liver is the primary target of toxicity in rodents following oral exposure. Due to the structural diversity of PFAS, the mode of action (MOA) can differ between PFAS for the same target tissue. There is significant evidence for involvement of peroxisome proliferator-activated receptor alpha (PPARα) activation based on molecular and histopathological responses in the liver following HFPO-DA exposure, but other MOAs have also been hypothesized based on limited evidence. The MOA underlying the liver effects in mice exposed to HFPO-DA was assessed in the context of the Key Events (KEs) outlined in the MOA framework for PPARα activator-induced rodent hepatocarcinogenesis. The first 3 KEs (ie, PPARα activation, alteration of cell growth pathways, and perturbation of cell growth/survival) are supported by several lines of evidence from both in vitro and in vivo data available for HFPO-DA. In contrast, alternate MOAs, including cytotoxicity, PPARγ and mitochondrial dysfunction are generally not supported by the scientific literature. HFPO-DA-mediated liver effects in mice are not expected in humans as only KE 1, PPARα activation, is shared across species. PPARα-mediated gene expression in humans produces only a subset (ie, lipid modulating effects) of the responses observed in rodents. As such, the adverse effects observed in rodent livers should not be used as the basis of toxicity values for HFPO-DA for purposes of human health risk assessment.
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Affiliation(s)
| | | | - James E Klaunig
- School of Public Health, Indiana University, Bloomington, Indiana 47405, USA
| | - John M Cullen
- North Carolina State University College of Veterinary Medicine, Raleigh, North Carolina 27606, USA
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7
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Dawson DE, Lau C, Pradeep P, Sayre RR, Judson RS, Tornero-Velez R, Wambaugh JF. A Machine Learning Model to Estimate Toxicokinetic Half-Lives of Per- and Polyfluoro-Alkyl Substances (PFAS) in Multiple Species. TOXICS 2023; 11:98. [PMID: 36850973 PMCID: PMC9962572 DOI: 10.3390/toxics11020098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/09/2023] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a diverse group of man-made chemicals that are commonly found in body tissues. The toxicokinetics of most PFAS are currently uncharacterized, but long half-lives (t½) have been observed in some cases. Knowledge of chemical-specific t½ is necessary for exposure reconstruction and extrapolation from toxicological studies. We used an ensemble machine learning method, random forest, to model the existing in vivo measured t½ across four species (human, monkey, rat, mouse) and eleven PFAS. Mechanistically motivated descriptors were examined, including two types of surrogates for renal transporters: (1) physiological descriptors, including kidney geometry, for renal transporter expression and (2) structural similarity of defluorinated PFAS to endogenous chemicals for transporter affinity. We developed a classification model for t½ (Bin 1: <12 h; Bin 2: <1 week; Bin 3: <2 months; Bin 4: >2 months). The model had an accuracy of 86.1% in contrast to 32.2% for a y-randomized null model. A total of 3890 compounds were within domain of the model, and t½ was predicted using the bin medians: 4.9 h, 2.2 days, 33 days, and 3.3 years. For human t½, 56% of PFAS were classified in Bin 4, 7% were classified in Bin 3, and 37% were classified in Bin 2. This model synthesizes the limited available data to allow tentative extrapolation and prioritization.
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Affiliation(s)
- Daniel E. Dawson
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, USA
| | - Christopher Lau
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, 109 T.W. Alexander Drive, Research Triangle Park, NC 277011, USA
| | - Prachi Pradeep
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, USA
- Oak Ridge Institutes for Science and Education, Oak Ridge, TN 37830, USA
| | - Risa R. Sayre
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, USA
| | - Richard S. Judson
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, USA
| | - Rogelio Tornero-Velez
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, USA
| | - John F. Wambaugh
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, USA
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8
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TAN D, WANG J, ZHANG Q, QIN L, WANG Y, HE Y. The role of organic anion transport protein 1a4 in drug delivery and diseases: a review. FOOD SCIENCE AND TECHNOLOGY 2023. [DOI: 10.1590/fst.114122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
| | | | | | - Lin QIN
- Zunyi Medical University, China
| | - Yuhe WANG
- Affiliated Hospital of Zunyi Medical University
| | - Yuqi HE
- Zunyi Medical University, China
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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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10
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Gebreab KY, Benetti D, Grosell M, Stieglitz JD, Berry JP. Toxicity of perfluoroalkyl substances (PFAS) toward embryonic stages of mahi-mahi (Coryphaena hippurus). ECOTOXICOLOGY (LONDON, ENGLAND) 2022; 31:1057-1067. [PMID: 35982347 DOI: 10.1007/s10646-022-02576-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
Perfluoroalkyl substances (PFAS) are highly persistent organic pollutants that have been detected in a wide array of environmental matrices and, in turn, diverse biota including humans and wildlife wherein they have been associated with a multitude of toxic, and otherwise adverse effects, including ecosystem impacts. In the present study, we developed a toxicity assay for embryonic stages of mahi-mahi (Coryphaena hippurus), as an environmentally relevant pelagic fish species, and applied this assay to the evaluation of the toxicity of "legacy" and "next-generation" PFAS including, respectively, perfluorooctanoic acid (PFOA) and several perfluoroethercarboxylic acids (PFECA). Acute embryotoxicity, in the form of lethality, was measured for all five PFAS toward mahi-mahi embryos with median lethal concentrations (LC50) in the micromolar range. Consistent with studies in other similar model systems, and specifically the zebrafish, embryotoxicity in mahi-mahi generally (1) correlated with fluoroalkyl/fluoroether chain length and hydrophobicity, i.e., log P, of PFAS, and thus, aligned with a role of uptake in the relative toxicity; and (2) increased with continuous exposure, suggesting a possible role of development stage specifically including a contribution of hatching (and loss of protective chorion) and/or differentiation of target systems (e.g., liver). Compared to prior studies in the zebrafish embryo model, mahi-mahi was significantly more sensitive to PFAS which may be related to differences in either exposure conditions (e.g., salinity) and uptake, or possibly differential susceptibility of relevant targets, for the two species. Moreover, when considered in the context of the previously reported concentration of PFAS within upper sea surface layers, and co-localization of buoyant eggs (i.e., embryos) and other early development stages (i.e., larvae, juveniles) of pelagic fish species to the sea surface, the observed toxicity potentially aligns with environmentally relevant concentrations in these marine systems. Thus, impacts on ecosystems including, in particular, population recruitment are a possibility. The present study is the first to demonstrate embryotoxicity of PFAS in a pelagic marine fish species, and suggests that mahi-mahi represents a potentially informative, and moreover, environmentally relevant, ecotoxicological model for PFAS in marine systems.
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Affiliation(s)
- Kiflom Y Gebreab
- Department of Chemistry and Biochemistry, Institute of Environment, Florida International University, North Miami, FL, USA
| | - Daniel Benetti
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Martin Grosell
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - John D Stieglitz
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - J P Berry
- Department of Chemistry and Biochemistry, Institute of Environment, Florida International University, North Miami, FL, USA.
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11
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Zhou S, Shu Y. Transcriptional Regulation of Solute Carrier (SLC) Drug Transporters. Drug Metab Dispos 2022; 50:DMD-MR-2021-000704. [PMID: 35644529 PMCID: PMC9488976 DOI: 10.1124/dmd.121.000704] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 05/02/2022] [Accepted: 05/16/2022] [Indexed: 09/03/2023] Open
Abstract
Facilitated transport is necessitated for large size, charged, and/or hydrophilic drugs to move across the membrane. The drug transporters in the solute carrier (SLC) superfamily, mainly including organic anion-transporting polypeptides (OATPs), organic anion transporters (OATs), organic cation transporters (OCTs), organic cation/carnitine transporters (OCTNs), peptide transporters (PEPTs), and multidrug and toxin extrusion proteins (MATEs), are critical facilitators of drug transport and distribution in human body. The expression of these SLC drug transporters is found in tissues throughout the body, with high abundance in the epithelial cells of major organs for drug disposition, such as intestine, liver, and kidney. These SLC drug transporters are clinically important in drug absorption, metabolism, distribution, and excretion. The mechanisms underlying their regulation have been revealing in recent years. Epigenetic and nuclear receptor-mediated transcriptional regulation of SLC drug transporters have particularly attracted much attention. This review focuses on the transcriptional regulation of major SLC drug transporter genes. Revealing the mechanisms underlying the transcription of those critical drug transporters will help us understand pharmacokinetics and pharmacodynamics, ultimately improving drug therapeutic effectiveness while minimizing drug toxicity. Significance Statement It has become increasingly recognized that solute carrier (SLC) drug transporters play a crucial, and sometimes determinative, role in drug disposition and response, which is reflected in decision-making during not only clinical drug therapy but also drug development. Understanding the mechanisms accounting for the transcription of these transporters is critical to interpret their abundance in various tissues under different conditions, which is necessary to clarify the pharmacological response, adverse effects, and drug-drug interactions for clinically used drugs.
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Affiliation(s)
- Shiwei Zhou
- Pharmaceutical Sciences, University of Maryland, United States
| | - Yan Shu
- Pharmaceutical Sciences, University of Maryland, United States
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12
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TAN D, CUI J, QIN L, CHEN L, WANG Y, ZHANG Q, HE Y. The role of OATP1A1 in cholestasis and drug-induced toxicity: a systematic review. FOOD SCIENCE AND TECHNOLOGY 2022. [DOI: 10.1590/fst.70722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | - Jinguo CUI
- Baodi Clinical College of Tianjin Medical University, China
| | - Lin QIN
- Zunyi Medical University, China
| | - Li CHEN
- Zunyi Medical University, China
| | - Yuhe WANG
- Affiliated Hospital of Zunyi Medical University, China
| | | | - Yuqi HE
- Zunyi Medical University, China
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13
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Marques ES, Agudelo J, Kaye EM, Modaresi SMS, Pfohl M, Bečanová J, Wei W, Polunas M, Goedken M, Slitt AL. The role of maternal high fat diet on mouse pup metabolic endpoints following perinatal PFAS and PFAS mixture exposure. Toxicology 2021; 462:152921. [PMID: 34464680 DOI: 10.1016/j.tox.2021.152921] [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] [Received: 02/05/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 01/09/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a family of chemicals that are ubiquitous in the environment. Some of these chemicals, such as perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonate (PFHxS) and perfluorooctanoic acid (PFOA), are found in human sera and have been shown to cause liver steatosis and reduce postnatal survival and growth in rodents. The purpose of this work is to evaluate the impact of diet and PFAS exposure to mouse dam (mus musculus) on the risk to pup liver and metabolism endpoints later in life, as well as evaluate PFAS partitioning to pups. Timed-pregnant dams were fed a standard chow diet or 60 % kcal high fat diet (HFD). Dams were administered either vehicle, 1 mg/kg PFOA, 1 mg/kg PFOS, 1 mg/kg PFHxS, or a PFAS mixture (1 mg/kg of each PFOA, PFOS, and PFHxS) daily via oral gavage from gestation day 1 until postnatal day (PND) 20. At PND 21, livers of dams and 2 pups of each sex were evaluated for lipid changes while remaining pups were weaned to the same diet as the dam for an additional 10 weeks. Dam and pup serum at PND 21 and PND 90 were also evaluated for PFAS concentration, alanine aminotransferase (ALT), leptin and adiponectin, and glycosylated hemoglobin A1c. Perinatal exposure to a HFD, as expected, increased pup body weight, maternal liver weight, pup liver triglycerides, pup serum ALT, and pup serum leptin. PFOA and the PFAS mixture increased liver weights, and. treatment with all three compounds increased liver triglycerides. The maternal HFD increased dam and pup serum PFAS levels, however, was protective against PFOA-induced increase in serum ALT and observed increases in liver triglycerides. The PFAS mixture had very distinct effects when compared to single compound treatment, suggesting some cumulative effects, particularly when evaluating PFAS transfer from dam to pup. This data highlights the importance of diet and mixtures when evaluating liver effect of PFAS and PFAS partitioning.
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Affiliation(s)
- Emily S Marques
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI 02881, USA
| | - Juliana Agudelo
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI 02881, USA
| | - Emily M Kaye
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI 02881, USA
| | - Seyed Mohamad Sadegh Modaresi
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI 02881, USA
| | - Marisa Pfohl
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI 02881, USA
| | - Jitka Bečanová
- Graduate School of Oceanography, University of Rhode Island, 215 S Ferry Rd, Narragansett, RI 02882, USA
| | - Wei Wei
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI 02881, USA
| | - Marianne Polunas
- Rutgers Translational Sciences, Rutgers University, 33 Knightsbridge Road, Piscataway, NJ 08854, USA
| | - Michael Goedken
- Rutgers Translational Sciences, Rutgers University, 33 Knightsbridge Road, Piscataway, NJ 08854, USA
| | - Angela L Slitt
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI 02881, USA.
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14
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Pfohl M, Marques E, Auclair A, Barlock B, Jamwal R, Goedken M, Akhlaghi F, Slitt AL. An 'Omics Approach to Unraveling the Paradoxical Effect of Diet on Perfluorooctanesulfonic Acid (PFOS) and Perfluorononanoic Acid (PFNA)-Induced Hepatic Steatosis. Toxicol Sci 2021; 180:277-294. [PMID: 33483757 DOI: 10.1093/toxsci/kfaa172] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Perfluoroalkyl substances (PFAS) are a family of toxicants universally detected in human serum and known to cause dyslipidemia in animals and humans. Hepatic steatosis, which is defined as lipid deposition in the liver, is known to be a consequence of poor diet. Similarly, PFAS are known to induce hepatic steatosis in animals on a low-fat chow. This study explored diet-PFAS interactions in the liver and their potential to modulate hepatic steatosis. Male C57BL/6J mice were fed with either a low-fat diet (10% kcal from fat, LFD) or a moderately high-fat diet (45% kcal from fat, HFD) with or without perfluorooctanesulfonic acid (3 ppm, PFOS) or perfluorononanoic acid (3 ppm, PFNA) in feed for 12 weeks. Livers were excised for histology and quantification of PFAS and lipids. The PFOS and PFNA coadministration with HFD reduced the hepatic accumulation of lipid and PFAS relative to the LFD treatment groups. Furthermore, transcriptomic analysis revealed that PFAS administration in the presence of an HFD significantly reduces expression of known hepatic PFAS uptake transporters, organic anion transporter proteins. Transcriptomics and proteomics further revealed several pathways related to lipid metabolism, synthesis, transport, and storage that were modulated by PFAS exposure and further impacted by the presence of dietary fat. Both dietary fat content and the chemical functional head group exerted significant influence on hepatic PFAS accumulation and the resulting biochemical signature, suggesting that diet and structure should be considered in the design and interpretation of research on PFAS induced hepatic steatosis.
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Affiliation(s)
- Marisa Pfohl
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
| | - Emily Marques
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
| | - Adam Auclair
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
| | - Benjamin Barlock
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
| | - Rohitash Jamwal
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
| | - Michael Goedken
- Rutgers Translational Sciences, Rutgers University, Piscataway, New Jersey 08901
| | - Fatemeh Akhlaghi
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
| | - Angela L Slitt
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
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15
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Singh N, Hsieh CYJ. Exploring Potential Carcinogenic Activity of Per- and Polyfluorinated Alkyl Substances Utilizing High-Throughput Toxicity Screening Data. Int J Toxicol 2021; 40:355-366. [PMID: 33944624 DOI: 10.1177/10915818211010490] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Per- and polyfluorinated alkyl substances (PFAS) are ubiquitous, persistent, and toxic chemicals that pose public health risks. Recent carcinogenicity concerns have arisen based on epidemiological studies, animal tumor findings, and mechanistic data. Thousands of PFAS exist; however, current understanding of their toxicity is informed by studies of a select few, namely, perfluorooctanoic acid and perfluorooctanesulfonic acid. Hence, the computational, high-throughput screening tool, the US EPA CompTox Chemical Dashboard's ToxCast, was utilized to explore the carcinogenicity potential of PFAS. Twenty-three major PFAS that had sufficient in vitro ToxCast data and covered a range of structural subclasses were analyzed with the visual analytics software ToxPi, yielding a qualitative and quantitative assessment of PFAS activity in realms closely linked with carcinogenicity. A comprehensive literature search was also conducted to check the consistency of analyses with other mechanistic data streams. The PFAS were found to induce a vast range of biological perturbations, in line with several of the International Agency for Research on Cancer-defined key carcinogen characteristics. Patterns observed varied by length of fluorine-bonded chains and/or functional group within and between each key characteristic, suggesting some structure-based variability in activity. In general, the major conclusions drawn from the analysis, that is, the most notable activities being modulation of receptor-mediated effects and induction of oxidative stress, were supported by literature findings. The study helps enhance understanding of the mechanistic pathways that underlie the potential carcinogenicity of various PFAS and hence could assist in hazard identification and risk assessment for this emerging and relevant class of environmental toxicants.
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Affiliation(s)
- Nalin Singh
- Office of Environmental Health Hazard Assessment, 7020California Environmental Protection Agency, Sacramento, CA, USA.,University of California, Davis, CA, USA
| | - Ching Yi Jennifer Hsieh
- Office of Environmental Health Hazard Assessment, 7020California Environmental Protection Agency, Sacramento, CA, USA
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16
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Bessonneau V, Gerona RR, Trowbridge J, Grashow R, Lin T, Buren H, Morello-Frosch R, Rudel RA. Gaussian graphical modeling of the serum exposome and metabolome reveals interactions between environmental chemicals and endogenous metabolites. Sci Rep 2021; 11:7607. [PMID: 33828161 PMCID: PMC8027000 DOI: 10.1038/s41598-021-87070-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 03/23/2021] [Indexed: 12/12/2022] Open
Abstract
Given the complex exposures from both exogenous and endogenous sources that an individual experiences during life, exposome-wide association studies that interrogate levels of small molecules in biospecimens have been proposed for discovering causes of chronic diseases. We conducted a study to explore associations between environmental chemicals and endogenous molecules using Gaussian graphical models (GGMs) of non-targeted metabolomics data measured in a cohort of California women firefighters and office workers. GGMs revealed many exposure-metabolite associations, including that exposures to mono-hydroxyisononyl phthalate, ethyl paraben and 4-ethylbenzoic acid were associated with metabolites involved in steroid hormone biosynthesis, and perfluoroalkyl substances were linked to bile acids-hormones that regulate cholesterol and glucose metabolism-and inflammatory signaling molecules. Some hypotheses generated from these findings were confirmed by analysis of data from the National Health and Nutrition Examination Survey. Taken together, our findings demonstrate a novel approach to discovering associations between chemical exposures and biological processes of potential relevance for disease causation.
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Affiliation(s)
- Vincent Bessonneau
- Silent Spring Institute, 320 Nevada Street, Newton, MA, 02460, USA
- Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement Et Travail) - UMR_S 1085, Univ. Rennes, 35000, Rennes, France
| | - Roy R Gerona
- Clinical Toxicology and Environmental Biomonitoring Lab, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA, USA
| | - Jessica Trowbridge
- School of Public Health, University of California, 130 Mulford, Hall #3144, Berkeley, CA, 94720, USA
| | - Rachel Grashow
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Thomas Lin
- Clinical Toxicology and Environmental Biomonitoring Lab, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA, USA
| | | | - Rachel Morello-Frosch
- School of Public Health, University of California, 130 Mulford, Hall #3144, Berkeley, CA, 94720, USA.
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA.
| | - Ruthann A Rudel
- Silent Spring Institute, 320 Nevada Street, Newton, MA, 02460, USA.
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17
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Gebreab KY, Eeza MNH, Bai T, Zuberi Z, Matysik J, O'Shea KE, Alia A, Berry JP. Comparative toxicometabolomics of perfluorooctanoic acid (PFOA) and next-generation perfluoroalkyl substances. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:114928. [PMID: 32540561 DOI: 10.1016/j.envpol.2020.114928] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/08/2020] [Accepted: 05/31/2020] [Indexed: 05/09/2023]
Abstract
Owing to environmental health concerns, a number of per- and polyfluoroalkyl substances (PFAS) have been phased-out, and increasingly replaced by various chemical analogs. Most prominent among these replacements are numerous perfluoroether carboxylic acids (PFECA). Toxicity, and environmental health concerns associated with these next-generation PFAS, however, remains largely unstudied. The zebrafish embryo was employed, in the present study, as a toxicological model system to investigate toxicity of a representative sample of PFECA, alongside perfluorooctanoic acid (PFOA) as one of the most widely used, and best studied, of the "legacy" PFAS. In addition, high-resolution magic angle spin (HRMAS) NMR was utilized for metabolic profiling of intact zebrafish embryos in order to characterize metabolic pathways associated with toxicity of PFAS. Acute embryotoxicity (i.e., lethality), along with impaired development, and variable effects on locomotory behavior, were observed for all PFAS in the zebrafish model. Median lethal concentration (LC50) was significantly correlated with alkyl chain-length, and toxic concentrations were quantitatively similar to those reported previously for PFAS. Metabolic profiling of zebrafish embryos exposed to selected PFAS, specifically including PFOA and two representative PFECA (i.e., GenX and PFO3TDA), enabled elaboration of an integrated model of the metabolic pathways associated with toxicity of these representative PFAS. Alterations of metabolic profiles suggested targeting of hepatocytes (i.e., hepatotoxicity), as well as apparent modulation of neural metabolites, and moreover, were consistent with a previously proposed role of mitochondrial disruption and peroxisome proliferator-activated receptor (PPAR) activation as reflected by dysfunctions of carbohydrate, lipid and amino acid metabolism, and consistent with a previously proposed contribution of PFAS to metabolic syndrome. Taken together, it was generally concluded that toxicity of PFECA is quantitatively and qualitatively similar to PFOA, and these analogs, likewise, represent potential concerns as environmental toxicants.
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Affiliation(s)
- Kiflom Y Gebreab
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
| | - Muhamed N H Eeza
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany; Institute for Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - Tianyu Bai
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany; Institute for Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - Zain Zuberi
- The School of Pharmacy and Pharmaceutical Sciences, Trinity College, Dublin, Ireland
| | - Jörg Matysik
- Institute for Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - Kevin E O'Shea
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
| | - A Alia
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany; Leiden Institute of Chemistry, Leiden University, 2333, Leiden, the Netherlands
| | - John P Berry
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA.
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18
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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, Hoogenboom L(R, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Vleminckx C, Wallace H, Barregård L, Ceccatelli S, Cravedi J, Halldorsson TI, Haug LS, Johansson N, Knutsen HK, Rose M, Roudot A, Van Loveren H, Vollmer G, Mackay K, Riolo F, Schwerdtle T. Risk to human health related to the presence of perfluoroalkyl substances in food. EFSA J 2020; 18:e06223. [PMID: 32994824 PMCID: PMC7507523 DOI: 10.2903/j.efsa.2020.6223] [Citation(s) in RCA: 223] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluoroalkyl substances (PFASs) in food. Based on several similar effects in animals, toxicokinetics and observed concentrations in human blood, the CONTAM Panel decided to perform the assessment for the sum of four PFASs: PFOA, PFNA, PFHxS and PFOS. These made up half of the lower bound (LB) exposure to those PFASs with available occurrence data, the remaining contribution being primarily from PFASs with short half-lives. Equal potencies were assumed for the four PFASs included in the assessment. The mean LB exposure in adolescents and adult age groups ranged from 3 to 22, the 95th percentile from 9 to 70 ng/kg body weight (bw) per week. Toddlers and 'other children' showed a twofold higher exposure. Upper bound exposure was 4- to 49-fold higher than LB levels, but the latter were considered more reliable. 'Fish meat', 'Fruit and fruit products' and 'Eggs and egg products' contributed most to the exposure. Based on available studies in animals and humans, effects on the immune system were considered the most critical for the risk assessment. From a human study, a lowest BMDL 10 of 17.5 ng/mL for the sum of the four PFASs in serum was identified for 1-year-old children. Using PBPK modelling, this serum level of 17.5 ng/mL in children was estimated to correspond to long-term maternal exposure of 0.63 ng/kg bw per day. Since accumulation over time is important, a tolerable weekly intake (TWI) of 4.4 ng/kg bw per week was established. This TWI also protects against other potential adverse effects observed in humans. Based on the estimated LB exposure, but also reported serum levels, the CONTAM Panel concluded that parts of the European population exceed this TWI, which is of concern.
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Zhang Y, Le Y, Bu P, Cheng X. Regulation of Hox and ParaHox genes by perfluorochemicals in mouse liver. Toxicology 2020; 441:152521. [PMID: 32534105 DOI: 10.1016/j.tox.2020.152521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/30/2020] [Accepted: 06/08/2020] [Indexed: 01/01/2023]
Abstract
Homeobox (Hox) genes encode homeodomain proteins, which play important roles in the development and morphological diversification of organisms including plants and animals. Perfluorinated chemicals (PFCs), which are well recognized industrial pollutants and universally detected in human and wildlife, interfere with animal development. In addition, PFCs produce a number of hepatic adverse effects, such as hepatomegaly and dyslipidemia. Homeodomain proteins profoundly contribute to liver regeneration. Hox genes serve as either oncogenes or tumor suppressor genes during target organ carcinogenesis. However, to date, no study investigated whether PFCs regulate expression of Hox genes. This study was designed to determine the regulation of Hox (including Hox-a to -d subfamily members) and paraHox [including GS homeobox (Gsx), pancreatic and duodenal homeobox (Pdx), and caudal-related homeobox (Cdx) family members] genes by PFCs including perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) in mouse liver. 46.4 mg/kg PFNA induced mRNA expression of Hoxa5, b7, c5, d10 and Pdx1 in wild-type and CAR-null mouse livers, but not in PPARα-null mouse livers, indicating a PPARα-dependent manner. PFOA, PFNA, and PFDA all induced mRNA expression of Hoxa5, b7, c5, d10, Pdx1 and Zeb2 in wild-type but not PPARα-null mouse livers. In addition, in Nrf2-null mouse livers, PFNA continued to increase mRNA expression of Hoxa5 and Pdx1, but not Hoxb7, c5 or d10. Furthermore, Wy14643, a classical PPARα agonist, induced mRNA expression of Hoxb7 and c5 in wild-type but not PPARα-null mouse livers. However, Wy14643 did not induce mRNA expression of Hoxa5, d10 or Pdx1 in either wild-type or PPARα-null mouse livers. TCPOBOP, a classical mouse CAR agonist, increased mRNA expression of Hoxb7, c5 and d10 but not Hoxa5 or Pdx1 in mouse livers. Moreover, PFNA decreased cytoplasmic and nuclear Hoxb7 protein levels in mouse livers. However, PFNA increased cytoplasmic Hoxc5 protein level but decreased nuclear Hoxc5 protein level in mouse livers. In conclusion, PFCs induced mRNA expression of several Hox genes such as Hoxb7, c5 and d10, mostly through the activation of PPARα and/or Nrf2 signaling.
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Affiliation(s)
- Yue Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, 11439, United States
| | - Yuan Le
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, 11439, United States
| | - Pengli Bu
- Department of Pharmaceutical Sciences, College of Pharmacy, Rosalind Franklin University of Medicine and Science, Chicago, IL, 60064, United States
| | - Xingguo Cheng
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, 11439, United States.
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20
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Bogdanska J, Borg D, Bergström U, Mellring M, Bergman Å, DePierre J, Nobel S. Tissue distribution of 14C-labelled perfluorooctanoic acid in adult mice after 1-5 days of dietary exposure to an experimental dose or a lower dose that resulted in blood levels similar to those detected in exposed humans. CHEMOSPHERE 2020; 239:124755. [PMID: 31726523 DOI: 10.1016/j.chemosphere.2019.124755] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/29/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
Perfluorooctanoic acid (PFOA), a global environmental pollutant detected in both wildlife and human populations, has several pathophysiological effects in experimental animals, including hepatotoxicity, immunotoxicity, and developmental toxicity. However, details concerning the tissue distribution of PFOA, in particular at levels relevant to humans, are lacking, which limits our understanding of how humans, and other mammals, may be affected by this compound. Therefore, we characterized the tissue distribution of 14C-PFOA in mice in the same manner as we earlier examined its analogues perfluorooctanesulfonate (PFOS) and perfluorobutanesulfonate (PFBS) in order to allow direct comparisons. Following dietary exposure of adult male C57/BL6 mice for 1, 3 or 5 days to a low dose (0.06 mg/kg/day) or a higher experimental dose (22 mg/kg/day) of 14C-PFOA, both scintillation counting and whole-body autoradiography revealed the presence of PFOA in most of the 19 different tissues examined, demonstrating its ability to leave the bloodstream and enter tissues. There were no differences in the pattern of tissue distribution with the low and high dose and the tissue-to-blood ratios were similar. At both doses, PFOA levels were highest in the liver, followed by blood, lungs and kidneys. The body compartments estimated to contain the largest amounts of PFOA were the liver, blood, skin and muscle. In comparison with our identical studies on PFOS and PFBS, PFOA reached considerably higher tissue levels than PFBS, but lower than PFOS. Furthermore, the distribution of PFOA differed notably from that of PFOS, with lower tissue-to-blood ratios in the liver, lungs, kidneys and skin.
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Affiliation(s)
- Jasna Bogdanska
- Department of Biochemistry and Biophysics, Stockholm University, SE-10691, Stockholm, Sweden.
| | - Daniel Borg
- Swedish Chemicals Agency, SE-17267, Stockholm, Sweden.
| | - Ulrika Bergström
- Department of Environmental Toxicology, Uppsala University, SE-75236, Uppsala, Sweden.
| | - Maria Mellring
- Department of Analytical Chemistry and Environmental Science, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Åke Bergman
- Department of Analytical Chemistry and Environmental Science, Stockholm University, SE-106 91, Stockholm, Sweden; School of Science and Technology, Örebro University, SE-701 82, Örebro, Sweden.
| | - Joseph DePierre
- Department of Biochemistry and Biophysics, Stockholm University, SE-10691, Stockholm, Sweden.
| | - Stefan Nobel
- Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institutet, SE-17177, Stockholm, Sweden.
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21
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Genetic resistance to DEHP-induced transgenerational endocrine disruption. PLoS One 2019; 14:e0208371. [PMID: 31181066 PMCID: PMC6557477 DOI: 10.1371/journal.pone.0208371] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/15/2019] [Indexed: 02/07/2023] Open
Abstract
Di(2-ethylhexyl)phthalate (DEHP) interferes with sex hormones signaling pathways (SHP). C57BL/6J mice prenatally exposed to 300 mg/kg/day DEHP develop a testicular dysgenesis syndrome (TDS) at adulthood, but similarly-exposed FVB/N mice are not affected. Here we aim to understand the reasons behind this drastic difference that should depend on the genome of the strain. In both backgrounds, pregnant female mice received per os either DEHP or corn oil vehicle and the male filiations were examined. Computer-assisted sperm analysis showed a DEHP-induced decreased sperm count and velocities in C57BL/6J. Sperm RNA sequencing experiments resulted in the identification of the 62 most differentially expressed RNAs. These RNAs, mainly regulated by hormones, produced strain-specific transcriptional responses to prenatal exposure to DEHP; a pool of RNAs was increased in FVB, another pool of RNAs was decreased in C57BL/6J. In FVB/N, analysis of non-synonymous single nucleotide polymorphisms (SNP) impacting SHP identified rs387782768 and rs29315913 respectively associated with absence of the Forkhead Box A3 (Foxa3) RNA and increased expression of estrogen receptor 1 variant 4 (NM_001302533) RNA. Analysis of the role of SNPs modifying SHP binding sites in function of strain-specific responses to DEHP revealed a DEHP-resistance allele in FVB/N containing an additional FOXA1-3 binding site at rs30973633 and four DEHP-induced beta-defensins (Defb42, Defb30, Defb47 and Defb48). A DEHP-susceptibility allele in C57BL/6J contained five SNPs (rs28279710, rs32977910, rs46648903, rs46677594 and rs48287999) affecting SHP and six genes (Svs2, Svs3b, Svs4, Svs3a, Svs6 and Svs5) epigenetically silenced by DEHP. Finally, targeted experiments confirmed increased methylation in the Svs3ab promoter with decreased SEMG2 persisting across generations, providing a molecular explanation for the transgenerational sperm velocity decrease found in C57BL/6J after DEHP exposure. We conclude that the existence of SNP-dependent mechanisms in FVB/N inbred mice may confer resistance to transgenerational endocrine disruption.
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Xie C, Takahashi S, Brocker CN, He S, Chen L, Xie G, Jang K, Gao X, Krausz KW, Qu A, Levi M, Gonzalez FJ. Hepatocyte peroxisome proliferator-activated receptor α regulates bile acid synthesis and transport. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1396-1411. [PMID: 31195146 DOI: 10.1016/j.bbalip.2019.05.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 02/05/2019] [Accepted: 05/28/2019] [Indexed: 12/12/2022]
Abstract
Peroxisome proliferator-activated receptor alpha (PPARα) controls lipid homeostasis through regulation of lipid transport and catabolism. PPARα activators are clinically used for hyperlipidemia treatment. The role of PPARα in bile acid (BA) homeostasis is beginning to emerge. Herein, Ppara-null and hepatocyte-specific Ppara-null (Ppara∆Hep) as well as the respective wild-type mice were treated with the potent PPARα agonist Wy-14,643 (Wy) and global metabolomics performed to clarify the role of hepatocyte PPARα in the regulation of BA homeostasis. Levels of all serum BAs were markedly elevated in Wy-treated wild-type mice but not in Ppara-null and Ppara∆Hep mice. Gene expression analysis showed that PPARα activation (1) down-regulated the expression of sodium-taurocholate acid transporting polypeptide and organic ion transporting polypeptide 1 and 4, responsible for the uptake of BAs into the liver; (2) decreased the expression of bile salt export pump transporting BA from hepatocytes into the bile canaliculus; (3) upregulated the expression of multidrug resistance-associated protein 3 and 4 transporting BA from hepatocytes into the portal vein. Moreover, there was a notable increase in the compositions of serum, hepatic and biliary cholic acid and taurocholic acid following Wy treatment, which correlated with the upregulated expression of the Cyp8b1 gene encoding sterol 12α-hydroxylase. The effects of Wy were identical between the Ppara∆Hep and Ppara-null mice. Hepatocyte PPARα controlled BA synthesis and transport not only via direct transcriptional regulation but also via crosstalk with hepatic farnesoid X receptor signaling. These findings underscore a key role for hepatocyte PPARα in the control of BA homeostasis.
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Affiliation(s)
- Cen Xie
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2089, United States of America; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China.
| | - Shogo Takahashi
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2089, United States of America; Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC, United States of America.
| | - Chad N Brocker
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2089, United States of America.
| | - Shijun He
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China.
| | - Li Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
| | - Guomin Xie
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Key Laboratory of Remodeling-Related Cardiovascular Diseases, Ministry of Education, Beijing 100069, PR China.
| | - Katrina Jang
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2089, United States of America.
| | - Xiaoxia Gao
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2089, United States of America.
| | - Kristopher W Krausz
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2089, United States of America.
| | - Aijuan Qu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Key Laboratory of Remodeling-Related Cardiovascular Diseases, Ministry of Education, Beijing 100069, PR China.
| | - Moshe Levi
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC, United States of America.
| | - Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2089, United States of America.
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Annunziato KM, Jantzen CE, Gronske MC, Cooper KR. Subtle morphometric, behavioral and gene expression effects in larval zebrafish exposed to PFHxA, PFHxS and 6:2 FTOH. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 208:126-137. [PMID: 30669116 PMCID: PMC6396680 DOI: 10.1016/j.aquatox.2019.01.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/11/2019] [Accepted: 01/11/2019] [Indexed: 05/06/2023]
Abstract
Recent studies of perfluoroalkylated substances (PFASs) have focused on the toxicity of long chain PFASs, such as PFOS or PFOA, which have been demonstrated to cause an array of developmental and behavioral effects. However, less is known about low molecular weight PFASs and alternatives. This study examined the morphometric and behavioral effects in zebrafish following developmental exposures of C6 PFASs: perfluorohexanoic acid, PFHxA, perfluorohexane sulfonate, PFHxS, and 6:2 fluorotelomer alcohol, 6:2 FTOH. Embryos were exposed to 0.02-20 μM concentrations of these compounds from the high stage (˜3 h post fertilization, hpf) until 120 hpf. Morphometric and gene expression endpoints were examined at 120 hpf. Genes selected for analysis were previously shown to be altered in zebrafish developmentally exposed to PFOS and PFOA. Additionally, exposed larvae were transferred to clean water and reared until 14 days post fertilization, dpf, when behavioral assays were completed and morphometric endpoints examined. While PFHxA was found to be the most acutely toxic at 120 hpf, few morphometric effects were observed. Gene expression was the most sensitive endpoint with significant increased tgfb1a, bdnf, and ap1s1 expression observed with PFHxA exposure. PFHxS exposure produced morphometric effects in the larvae, specifically increased length and yolk sac area at 2 and 20 μM. This phenotype persisted to the 14 dpf time point, where these larvae additionally displayed decreased distance traveled and crosses through the center of the arena of the behavioral assay. Exposure to 6:2 FTOH caused no morphometric effects at 120 hpf, and this compound was the least acutely toxic. However, expression of both tgfb1a and bdnf were increased by greater than 2 fold change at this time point. Effects also persisted to 14 dpf where a significant increase in distance traveled and velocity were observed in the behavioral assay. This study demonstrates effects on behavioral, morphometric and gene expression endpoints with developmental PFHxA, PFHxS, and 6:2 FTOH exposures in zebrafish.
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Affiliation(s)
- Kate M Annunziato
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.
| | - Carrie E Jantzen
- Department of Environmental Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - Melissa C Gronske
- Department of Animal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - Keith R Cooper
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA; Department of Environmental Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA; Department of Animal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.
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24
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Hoogenboom LR, Nebbia CS, Oswald IP, Petersen A, Rose M, Roudot AC, Vleminckx C, Vollmer G, Wallace H, Bodin L, Cravedi JP, Halldorsson TI, Haug LS, Johansson N, van Loveren H, Gergelova P, Mackay K, Levorato S, van Manen M, Schwerdtle T. Risk to human health related to the presence of perfluorooctane sulfonic acid and perfluorooctanoic acid in food. EFSA J 2018. [PMID: 32625773 DOI: 10.2903/j.efsa.2018.5194">10.2903/j.efsa.2018.5194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [10.2903/j.efsa.2018.5194','32625773', '10.1093/toxsci/kfn161')">Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023] Open
10.2903/j.efsa.2018.5194" />
Abstract
The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in food. Regarding PFOS and PFOA occurrence, the final data set available for dietary exposure assessment contained a total of 20,019 analytical results (PFOS n = 10,191 and PFOA n = 9,828). There were large differences between upper and lower bound exposure due to analytical methods with insufficient sensitivity. The CONTAM Panel considered the lower bound estimates to be closer to true exposure levels. Important contributors to the lower bound mean chronic exposure were 'Fish and other seafood', 'Meat and meat products' and 'Eggs and egg products', for PFOS, and 'Milk and dairy products', 'Drinking water' and 'Fish and other seafood' for PFOA. PFOS and PFOA are readily absorbed in the gastrointestinal tract, excreted in urine and faeces, and do not undergo metabolism. Estimated human half-lives for PFOS and PFOA are about 5 years and 2-4 years, respectively. The derivation of a health-based guidance value was based on human epidemiological studies. For PFOS, the increase in serum total cholesterol in adults, and the decrease in antibody response at vaccination in children were identified as the critical effects. For PFOA, the increase in serum total cholesterol was the critical effect. Also reduced birth weight (for both compounds) and increased prevalence of high serum levels of the liver enzyme alanine aminotransferase (ALT) (for PFOA) were considered. After benchmark modelling of serum levels of PFOS and PFOA, and estimating the corresponding daily intakes, the CONTAM Panel established a tolerable weekly intake (TWI) of 13 ng/kg body weight (bw) per week for PFOS and 6 ng/kg bw per week for PFOA. For both compounds, exposure of a considerable proportion of the population exceeds the proposed TWIs.
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25
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Hoogenboom LR, Nebbia CS, Oswald IP, Petersen A, Rose M, Roudot AC, Vleminckx C, Vollmer G, Wallace H, Bodin L, Cravedi JP, Halldorsson TI, Haug LS, Johansson N, van Loveren H, Gergelova P, Mackay K, Levorato S, van Manen M, Schwerdtle T. Risk to human health related to the presence of perfluorooctane sulfonic acid and perfluorooctanoic acid in food. EFSA J 2018; 16:e05194. [PMID: 32625773 PMCID: PMC7009575 DOI: 10.2903/j.efsa.2018.5194] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in food. Regarding PFOS and PFOA occurrence, the final data set available for dietary exposure assessment contained a total of 20,019 analytical results (PFOS n = 10,191 and PFOA n = 9,828). There were large differences between upper and lower bound exposure due to analytical methods with insufficient sensitivity. The CONTAM Panel considered the lower bound estimates to be closer to true exposure levels. Important contributors to the lower bound mean chronic exposure were 'Fish and other seafood', 'Meat and meat products' and 'Eggs and egg products', for PFOS, and 'Milk and dairy products', 'Drinking water' and 'Fish and other seafood' for PFOA. PFOS and PFOA are readily absorbed in the gastrointestinal tract, excreted in urine and faeces, and do not undergo metabolism. Estimated human half-lives for PFOS and PFOA are about 5 years and 2-4 years, respectively. The derivation of a health-based guidance value was based on human epidemiological studies. For PFOS, the increase in serum total cholesterol in adults, and the decrease in antibody response at vaccination in children were identified as the critical effects. For PFOA, the increase in serum total cholesterol was the critical effect. Also reduced birth weight (for both compounds) and increased prevalence of high serum levels of the liver enzyme alanine aminotransferase (ALT) (for PFOA) were considered. After benchmark modelling of serum levels of PFOS and PFOA, and estimating the corresponding daily intakes, the CONTAM Panel established a tolerable weekly intake (TWI) of 13 ng/kg body weight (bw) per week for PFOS and 6 ng/kg bw per week for PFOA. For both compounds, exposure of a considerable proportion of the population exceeds the proposed TWIs.
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26
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Zhang Y, Zhang Y, Klaassen CD, Cheng X. Alteration of Bile Acid and Cholesterol Biosynthesis and Transport by Perfluorononanoic Acid (PFNA) in Mice. Toxicol Sci 2018; 162:225-233. [PMID: 29112762 PMCID: PMC6693384 DOI: 10.1093/toxsci/kfx237] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Perfluorochemicals produce hepatotoxic effects via activation of peroxisome proliferator-activated receptor alpha (PPARα) and constitutive androstane receptor (CAR) nuclear receptors in animals. Bile formation is one major liver function. But it remains unknown whether perfluorochemicals alter metabolism of bile acids (BAs) in liver. The present study was designed to determine the impact of perfluorononanoic acid (PFNA) on BA and cholesterol homeostasis in mice. A single dose of PFNA (0.1 mmol/kg) was intraperitoneally administered to adult male wild-type (WT), PPARα-null, and CAR-null mice. PFNA caused cholestasis in the WT mice, indicated by increased serum alanine aminotransferase, hyperbilirubinemia, elevated BA concentrations in mouse serum, and appearance of bile plugs in mouse liver. In addition, PFNA decreased total and some individual BAs in mouse liver. PFNA increased the concentrations of total and taurine-conjugated, as well as some individual BAs in the serum of WT and CAR-null mice but not in PPARα-null mice, indicating a PPARα-dependent mechanism. PFNA decreased mRNA expression of most BA-related transporters (sodium-taurocholate cotransporting polypeptide, organic anion transporting polypeptide [Oatp]1a1, Oatp1b2, and bile salt export pump) and BA biosynthetic enzymes (Cyp7a1, 7b1, 8b1, and 27a1) in mouse liver, but increased mRNA expression of some efflux transporters (breast cancer resistance protein, multidrug resistance transporter 2, multidrug resistance-associated protein [Mrp] 2, Mrp3, and Mrp4), primarily via a PPARα-dependent mechanism. Moreover, PFNA increased free and total cholesterol in mouse liver but not in mouse serum. Furthermore, PFNA increased mRNA expression of sterol transporters, namely Abca1, g1, g5/g8, and steroidogenic acute regulatory protein via PPARα. In conclusion, PFNA produced cholestasis in mouse liver, and the activation of PPARα plays a central role in regulating BA and cholesterol metabolism and transport in mouse serum and liver.
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Affiliation(s)
- Yue Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John’s University, Jamaica, New York 11439
| | - Youcai Zhang
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, P.R. China
| | - Curtis D Klaassen
- Department of Environmental & Occupational Health Sciences, School of Public Health, University of Washington, Seattle, Washington 98195
| | - Xingguo Cheng
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John’s University, Jamaica, New York 11439
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27
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PPARα-independent transcriptional targets of perfluoroalkyl acids revealed by transcript profiling. Toxicology 2017; 387:95-107. [PMID: 28558994 DOI: 10.1016/j.tox.2017.05.013] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/17/2017] [Accepted: 05/23/2017] [Indexed: 01/09/2023]
Abstract
Perfluoroalkyl acids (PFAAs) are ubiquitous and persistent environmental contaminants. Compounds such as perfluoroocanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS) are readily found in the tissues of humans and wildlife. While PFOA and PFOS have been the subject of numerous studies since they were first described over a decade ago, less is known about the biological activity of PFHxS and PFNA. Most PFAAs are activators of peroxisome proliferator-activated receptor α (PPARα), although the biological effects of these compounds are likely mediated by other factors in addition to PPARα. To evaluate the effects of PFHxS and PFNA, male wild-type and Pparα-null mice were dosed by oral gavage with PFHxS (3 or 10mg/kg/day), PFNA (1 or 3mg/kg/day), or vehicle for 7days, and liver gene expression was evaluated by full-genome microarrays. Gene expression patterns were then compared to historical in-house data for PFOA and PFOS in addition to the experimental hypolipidemic agent, WY-14,643. While WY-14,643 altered most genes in a PPARα-dependent manner, approximately 11-24% of regulated genes in PFAA-treated mice were independent of PPARα. The possibility that PFAAs regulate gene expression through other molecular pathways was evaluated. Using data available through a microarray database, PFAA gene expression profiles were found to exhibit significant similarity to profiles from mouse tissues exposed to agonists of the constitutive activated receptor (CAR), estrogen receptor α (ERα), and PPARγ. Human PPARγ and ERα were activated by all four PFAAs in trans-activation assays from the ToxCast screening program. Predictive gene expression biomarkers showed that PFAAs activate CAR in both genotypes and cause feminization of the liver transcriptome through suppression of signal transducer and activator of transcription 5B (STAT5B). These results indicate that, in addition to activating PPARα as a primary target, PFAAs also have the potential to activate CAR, PPARγ, and ERα as well as suppress STAT5B.
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28
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Dong T, Peng Y, Zhong N, Liu F, Zhang H, Xu M, Liu R, Han M, Tian X, Jia J, Chang LK, Guo LH, Liu S. Perfluorodecanoic acid (PFDA) promotes gastric cell proliferation via sPLA2-IIA. Oncotarget 2017; 8:50911-50920. [PMID: 28881615 PMCID: PMC5584216 DOI: 10.18632/oncotarget.17284] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 04/05/2017] [Indexed: 01/09/2023] Open
Abstract
The association of perfluorodecanoicacid (PFDA) with tumor promotion and associated effects is not clear. Given that PDFA is mostly consumed with food and drinking water, we evaluated the effects of PFDA on a gastric cell line. When added to cell cultures, PFDA significantly increased growth rate and colony forming ability compared with control treatment. We found that suppression of cell senescence, but not apoptosis or autophagy was associated with PFDA-induced promotion of cell amount. To determine the molecular mechanism that was involved, DNA microarray assays was used to analyze changes in gene expression in response to PFDA treatment. Data analysis demonstrated that the vascular endothelial growth factor signaling pathway had the lowest p-value, with sPLA2-IIA (pla2g2a) exhibits the most altered expression pattern within the pathway. Moreover, sPLA2-IIA and its transcription factor TCF4, known as a direct target and a binding partner of Wnt/β-catenin signaling in gastric cells respectively, were the third and second most varied genes globally. Cells transfected with expression plasmids pENTER-tcf4 and pENTER-pla2g2a show reduced cell proliferation by more than 60% and 30% respectively. Knockdown with sPLA2-IIA siRNA provided additional evidence that sPLA2-IIA was a mediator of PFDA-induced cell senescence suppression. The results suggest for the first time that PFDA induced suppression of cell senescence through inhibition of sPLA2-IIA protein expression and might increased the proliferative capacity of an existing tumor.
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Affiliation(s)
- Tianyi Dong
- School of Medicine, Shandong University, Jinan, Shandong, 250012, China.,Department of Breast Thyroid Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, 250021, China
| | - Yanping Peng
- School of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Ning Zhong
- Department of Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Fengyan Liu
- Department of Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Hanyu Zhang
- School of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Mengchen Xu
- School of Environmental Science and Engineering, Shandong University, Jinan, Shandong, 250100, China
| | - Rutao Liu
- School of Environmental Science and Engineering, Shandong University, Jinan, Shandong, 250100, China
| | - Mingyong Han
- Cancer Therapy and Research Center, Shandong Provincial Hospital, Shandong university, Jinan, Shandong 250021, China
| | - Xingsong Tian
- Department of Breast Thyroid Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, 250021, China
| | - Jihui Jia
- School of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Lap Kam Chang
- School of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Liang-Hong Guo
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Shili Liu
- School of Medicine, Shandong University, Jinan, Shandong, 250012, China
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Vogeler S, Galloway TS, Isupov M, Bean TP. Cloning retinoid and peroxisome proliferator-activated nuclear receptors of the Pacific oyster and in silico binding to environmental chemicals. PLoS One 2017; 12:e0176024. [PMID: 28426724 PMCID: PMC5398557 DOI: 10.1371/journal.pone.0176024] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 04/04/2017] [Indexed: 01/15/2023] Open
Abstract
Disruption of nuclear receptors, a transcription factor superfamily regulating gene expression in animals, is one proposed mechanism through which pollution causes effects in aquatic invertebrates. Environmental pollutants have the ability to interfere with the receptor's functions through direct binding and inducing incorrect signals. Limited knowledge of invertebrate endocrinology and molecular regulatory mechanisms, however, impede the understanding of endocrine disruptive effects in many aquatic invertebrate species. Here, we isolated three nuclear receptors of the Pacific oyster, Crassostrea gigas: two isoforms of the retinoid X receptor, CgRXR-1 and CgRXR-2, a retinoic acid receptor ortholog CgRAR, and a peroxisome proliferator-activated receptor ortholog CgPPAR. Computer modelling of the receptors based on 3D crystal structures of human proteins was used to predict each receptor's ability to bind to different ligands in silico. CgRXR showed high potential to bind and be activated by 9-cis retinoic acid and the organotin tributyltin (TBT). Computer modelling of CgRAR revealed six residues in the ligand binding domain, which prevent the successful interaction with natural and synthetic retinoid ligands. This supports an existing theory of loss of retinoid binding in molluscan RARs. Modelling of CgPPAR was less reliable due to high discrepancies in sequence to its human ortholog. Yet, there are suggestions of binding to TBT, but not to rosiglitazone. The effect of potential receptor ligands on early oyster development was assessed after 24h of chemical exposure. TBT oxide (0.2μg/l), all-trans retinoic acid (ATRA) (0.06 mg/L) and perfluorooctanoic acid (20 mg/L) showed high effects on development (>74% abnormal developed D-shelled larvae), while rosiglitazone (40 mg/L) showed no effect. The results are discussed in relation to a putative direct (TBT) disruption effect on nuclear receptors. The inability of direct binding of ATRA to CgRAR suggests either a disruptive effect through a pathway excluding nuclear receptors or an indirect interaction. Our findings provide valuable information on potential mechanisms of molluscan nuclear receptors and the effects of environmental pollution on aquatic invertebrates.
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Affiliation(s)
- Susanne Vogeler
- School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
- Centre for Environment, Fisheries and Aquaculture Science, Cefas Weymouth Laboratory, Weymouth, United Kingdom
| | - Tamara S. Galloway
- School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Michail Isupov
- School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Tim P. Bean
- Centre for Environment, Fisheries and Aquaculture Science, Cefas Weymouth Laboratory, Weymouth, United Kingdom
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Recent experimental results of effects of perfluoroalkyl substances in laboratory animals - Relation to current regulations and guidance values. Int J Hyg Environ Health 2017; 220:766-775. [PMID: 28286084 DOI: 10.1016/j.ijheh.2017.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 02/23/2017] [Accepted: 03/01/2017] [Indexed: 01/27/2023]
Abstract
The detection of perfluoroalkyl substances (PFAS) in surface and drinking water from various countries raised the attention to the presence of these chemicals in environmental probes and led to several regulatory actions to limit exposure in human beings. There was particular concern about perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), due to their former wide-spread use. Recently, several institutions published revisions of former regulatory or recommended maximum concentrations in drinking water and food, which are markedly lower than the former values. The present short overview describes the current regulations for PFAS and compares them with the outcome of several experimental studies in laboratory animals at low-level exposure to PFOA and PFOS. In addition, regulations for short-chain PFAS are presented which, due to lack of toxicological information, are evaluated according to the concepts of Threshold of Toxicological Concern (TTC) or the Health-related Indication Values (HRIV).
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Crosstalk of HNF4 α with extracellular and intracellular signaling pathways in the regulation of hepatic metabolism of drugs and lipids. Acta Pharm Sin B 2016; 6:393-408. [PMID: 27709008 PMCID: PMC5045537 DOI: 10.1016/j.apsb.2016.07.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 05/05/2016] [Accepted: 05/11/2016] [Indexed: 12/15/2022] Open
Abstract
The liver is essential for survival due to its critical role in the regulation of metabolic homeostasis. Metabolism of xenobiotics, such as environmental chemicals and drugs by the liver protects us from toxic effects of these xenobiotics, whereas metabolism of cholesterol, bile acids (BAs), lipids, and glucose provide key building blocks and nutrients to promote the growth or maintain the survival of the organism. As a well-established master regulator of liver development and function, hepatocyte nuclear factor 4 alpha (HNF4α) plays a critical role in regulating a large number of key genes essential for the metabolism of xenobiotics, metabolic wastes, and nutrients. The expression and activity of HNF4α is regulated by diverse hormonal and signaling pathways such as growth hormone, glucocorticoids, thyroid hormone, insulin, transforming growth factor-β, estrogen, and cytokines. HNF4α appears to play a central role in orchestrating the transduction of extracellular hormonal signaling and intracellular stress/nutritional signaling onto transcriptional changes in the liver. There have been a few reviews on the regulation of drug metabolism, lipid metabolism, cell proliferation, and inflammation by HNF4α. However, the knowledge on how the expression and transcriptional activity of HNF4α is modulated remains scattered. Herein I provide comprehensive review on the regulation of expression and transcriptional activity of HNF4α, and how HNF4α crosstalks with diverse extracellular and intracellular signaling pathways to regulate genes essential in liver pathophysiology.
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Dual action of peroxisome proliferator-activated receptor alpha in perfluorodecanoic acid-induced hepatotoxicity. Arch Toxicol 2016; 91:897-907. [PMID: 27344344 DOI: 10.1007/s00204-016-1779-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 06/20/2016] [Indexed: 10/21/2022]
Abstract
Perfluorodecanoic acid (PFDA) is widely used in production of many daily necessities based on their surface properties and stability. It was assigned as a Persistent Organic Pollutant in 2009 and became a public concern partly because of its potential for activation of the peroxisome proliferator-activated receptor alpha (PPARα). In this study, wild-type and Ppara-null mice were administered PFDA (80 mg/kg). Blood and liver tissues were collected and subjected to systemic toxicological and mechanistic analysis. UPLC-ESI-QTOFMS-based metabolomics was used to explore the contributing components of the serum metabolome that led to variation between wild-type and Pparα-null mice. Bile acid homeostasis was disrupted, and slight hepatocyte injury in wild-type mice accompanied by adaptive regulation of bile acid synthesis and transport was observed. The serum metabolome in wild-type clustered differently from that in Pparα-null, featured by sharp increases in bile acid components. Differential toxicokinetic tendency was supported by regulation of UDP-glucuronosyltransferases dependent on PPARα, but it did not contribute to the hepatotoxic responses. Increase in Il-10 and activation of the JNK pathway indicated inflammation was induced by disruption of bile acid homeostasis in wild-type mice. Inhibition of p-p65 dependent on PPARα activation by PFDA stopped the inflammatory cascade, as indicated by negative response of Il-6, Tnf-α, and STAT3 signaling. These data suggest disruptive and protective role of PPARα in hepatic responses induced by PFDA.
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Abstract
Atherosclerosis is a chronic inflammatory disease with deposition of excessive cholesterol in the arterial intima. Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor that can activate or inhibit the expression of many target genes by forming a heterodimer complex with the retinoid X receptor. Activation of PPARα plays an important role in the metabolism of multiple lipids, including high-density lipoprotein, cholesterol, low-density lipoprotein, triglyceride, phospholipid, bile acids, and fatty acids. Increased PPARα activity also mitigates atherosclerosis by blocking macrophage foam cell formation, vascular inflammation, vascular smooth muscle cell proliferation and migration, plaque instability, and thrombogenicity. Clinical use of synthetic PPARα agonist fibrate improved dyslipidemia and attenuated atherosclerosis-related disease risk. This review summarizes PPARα in lipid and lipoprotein metabolism and atherosclerosis, and also highlights its potential therapeutic benefits.
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Everds NE, Kennedy GL. Serum perfluorooctanoic acid (PFOA) concentrations in normal and hyperlipidemic female hamsters dosed orally with ammonium perfluorooctanoate (APFO) for up to 30 days. Toxicol Rep 2015; 2:70-77. [PMID: 28962339 PMCID: PMC5598093 DOI: 10.1016/j.toxrep.2015.01.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/23/2015] [Accepted: 01/25/2015] [Indexed: 02/02/2023] Open
Abstract
In epidemiology studies, the presence of perfluorooctanoate (PFOA) in human blood has been associated with higher serum cholesterol concentrations. A possible explanation for these results is that elevated serum cholesterol might reduce clearance of PFOA. In this study, female hamsters, which transport and regulate cholesterol in a manner similar to humans, were fed normal diet or diet supplemented with 0.05% cholesterol and 10% coconut oil (high-fat diet) resulting in hyperlipidemia throughout the study in supplemented animals. Hamsters on either a normal and high-fat diet were given oral doses of 0.1, 1.0, or 10 mg APFO/kg for 30 days. Serum PFOA concentrations evaluated 24 h after 1, 10, 20, and 30 doses of APFO were not altered in hyperlipidemic hamsters compared to those fed normal diet. For a given dose group, serum concentrations of PFOA were highest following the 10 doses (except for the 10 mg/kg group where concentrations were the highest after the first dose) and were lowest after 20 and 30 doses. Under the condition of this study, higher serum lipids did not affect the absorption and clearance of serum PFOA. Serum PFOA concentrations declined over the course of the study despite continued daily dosing with APFO. This does not support the hypothesis that higher serum lipids might increase the retention of PFOA in the body.
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Affiliation(s)
- Nancy E Everds
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE, USA.,Department of Pathology, Amgen, Inc., Seattle, WA, USA
| | - Gerald L Kennedy
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE, USA.,DuPont Sustainable Growth Center, Health and Environmental Sciences, Wilmington, DE, USA
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Yao PL, Ehresman DJ, Rae JMC, Chang SC, Frame SR, Butenhoff JL, Kennedy GL, Peters JM. Comparative in vivo and in vitro analysis of possible estrogenic effects of perfluorooctanoic acid. Toxicology 2014; 326:62-73. [PMID: 25456267 DOI: 10.1016/j.tox.2014.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 10/09/2014] [Accepted: 10/17/2014] [Indexed: 11/25/2022]
Abstract
Previous studies suggested that perfluorooctanoate (PFOA) could activate the estrogen receptor (ER). The present study examined the hypothesis that PFOA can activate ER using an in vivo uterotrophic assay in CD-1 mice and an in vitro reporter assay. Pre-pubertal female CD-1 mice fed an estrogen-free diet from postnatal day (PND)14 through weaning on PND18 were administered 0, 0.005, 0.01, 0.02, 0.05, 0.1, or 1mg/kg PFOA or 17β-estradiol (E2, 0.5mg/kg) from PND18-20. In contrast to E2, PFOA caused no changes in the relative uterine weight, the expression of ER target genes, or the morphology of the uterus/cervix and/or vagina on PND21. Treatment of a stable human cell line containing an ER-dependent luciferase reporter construct with a broad concentration range of PFOA caused no change in ER-dependent luciferase activity; whereas E2 caused a marked increase of ER-dependent luciferase activity. These data indicate that PFOA does not activate mouse or human ER.
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Affiliation(s)
- Pei-Li Yao
- Department of Veterinary and Biomedical Sciences and The Center of Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802, USA
| | | | | | | | - Steven R Frame
- Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19701, USA
| | | | | | - Jeffrey M Peters
- Department of Veterinary and Biomedical Sciences and The Center of Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802, USA.
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Ng CA, Hungerbühler K. Bioaccumulation of perfluorinated alkyl acids: observations and models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:4637-48. [PMID: 24762048 DOI: 10.1021/es404008g] [Citation(s) in RCA: 223] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this review, we consider the two prevailing hypotheses for the mechanisms that control the bioaccumulation of perfluorinated alkyl acids (PFAAs). The first assumes that partitioning to membrane phospholipids, which have a higher affinity for charged species than neutral storage lipids, can explain the high bioaccumulation potential of these compounds. The second assumes that interactions with proteins--including serum albumin, liver fatty acid binding proteins (L-FABP), and organic anion transporters--determine the distribution, accumulation and half-lives of PFAAs. We consider three unique phenomena to evaluate the two models: (1) observed patterns of tissue distribution in the laboratory and field, (2) the relationship between perfluorinated chain length and bioaccumulation, and (3) species- and gender-specific variation in elimination half-lives. Through investigation of these three characteristics of PFAA bioaccumulation, we show the strengths and weaknesses of the two modeling approaches. We conclude that the models need not be mutually exclusive, but that protein interactions are needed to explain some important features of PFAA bioaccumulation. Although open questions remain, further research should include perfluorinated alkyl substances (PFASs) beyond the long-chain PFAAs, as these substances are being phased out and replaced by a wide variety of PFASs with largely unknown properties and bioaccumulation behavior.
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Affiliation(s)
- Carla A Ng
- Safety and Environmental Technology Group, Institute for Chemical and Bioengineering, ETH Zurich , Zurich 8093, Switzerland
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Li F, Patterson AD, Krausz KW, Tanaka N, Gonzalez FJ. Metabolomics reveals an essential role for peroxisome proliferator-activated receptor α in bile acid homeostasis. J Lipid Res 2012; 53:1625-35. [PMID: 22665165 PMCID: PMC3540854 DOI: 10.1194/jlr.m027433] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 06/04/2012] [Indexed: 12/15/2022] Open
Abstract
Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor that regulates fatty acid transport and metabolism. Previous studies revealed that PPARα can affect bile acid metabolism; however, the mechanism by which PPARα regulates bile acid homeostasis is not understood. In this study, an ultraperformance liquid chromatography coupled with electrospray ionization qua dru pole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS)-based metabolomics approach was used to profile metabolites in urine, serum, and bile of wild-type and Ppara-null mice following cholic acid (CA) dietary challenge. Metabolomic analysis showed that the levels of several serum bile acids, such as CA (25-fold) and taurocholic acid (16-fold), were significantly increased in CA-treated Ppara-null mice compared with CA-treated wild-type mice. Phospholipid homeostasis, as revealed by decreased serum lysophos phati dylcholine (LPC) 16:0 (1.6-fold) and LPC 18:0 (1.6-fold), and corticosterone metabolism noted by increased urinary excretion of 11β-hydroxy-3,20-dioxopregn-4-en-21-oic acid (20-fold) and 11β,20α-dihydroxy-3-oxo-pregn-4-en-21-oic acid (3.6-fold), were disrupted in CA-treated Ppara-null mice. The hepatic levels of mRNA encoding transporters Abcb11, Abcb4, Abca1, Abcg5, and Abcg8 were diminished in Ppara-null mice, leading to the accumulation of bile acids in the liver during the CA challenge. These observations revealed that PPARα is an essential regulator of bile acid biosynthesis, transport, and secretion.
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Affiliation(s)
- Fei Li
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD; and
| | - Andrew D. Patterson
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD; and
- Department of Veterinary and Biomedical Sciences and Pennsylvania State University, University Park, PA
- Center for Molecular Toxicology and Carcinogenesis, Pennsylvania State University, University Park, PA
| | - Kristopher W. Krausz
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD; and
| | - Naoki Tanaka
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD; and
| | - Frank J. Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD; and
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More VR, Wen X, Thomas PE, Aleksunes LM, Slitt AL. Severe diabetes and leptin resistance cause differential hepatic and renal transporter expression in mice. COMPARATIVE HEPATOLOGY 2012; 11:1. [PMID: 22524730 PMCID: PMC3416584 DOI: 10.1186/1476-5926-11-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 04/23/2012] [Indexed: 12/29/2022]
Abstract
Background Type-2 Diabetes is a major health concern in the United States and other Westernized countries, with prevalence increasing yearly. There is a need to better model and predict adverse drug reactions, drug-induced liver injury, and drug efficacy in this population. Because transporters significantly contribute to drug clearance and disposition, it is highly significant to determine whether a severe diabetes phenotype alters drug transporter expression, and whether diabetic mouse models have altered disposition of acetaminophen (APAP) metabolites. Results Transporter mRNA and protein expression were quantified in livers and kidneys of adult C57BKS and db/db mice, which have a severe diabetes phenotype due to a lack of a functional leptin receptor. The urinary excretion of acetaminophen-glucuronide, a substrate for multidrug resistance-associated proteins transporters was also determined. The mRNA expression of major uptake transporters, such as organic anion transporting polypeptide Slco1a1 in liver and kidney, 1a4 in liver, and Slc22a7 in kidney was decreased in db/db mice. In contrast, Abcc3 and 4 mRNA and protein expression was more than 2 fold higher in db/db male mouse livers as compared to C57BKS controls. Urine levels of APAP-glucuronide, -sulfate, and N-acetyl cysteine metabolites were higher in db/db mice. Conclusion A severe diabetes phenotype/presentation significantly altered drug transporter expression in liver and kidney, which corresponded with urinary APAP metabolite levels.
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Affiliation(s)
- Vijay R More
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, 02881, USA.
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Loccisano AE, Campbell JL, Butenhoff JL, Andersen ME, Clewell HJ. Comparison and evaluation of pharmacokinetics of PFOA and PFOS in the adult rat using a physiologically based pharmacokinetic model. Reprod Toxicol 2011; 33:452-467. [PMID: 21565266 DOI: 10.1016/j.reprotox.2011.04.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/22/2011] [Accepted: 04/23/2011] [Indexed: 01/13/2023]
Abstract
Perfluoroalkyl acid carboxylates and sulfonates (PFAAs) have many consumer and industrial applications. The persistence and widespread distribution of PFAAs have brought them under intense scrutiny. Limited PK data for PFAAs is available for humans; however, toxicological and pharmacokinetic data exist for rats, which can be useful for cross-species extrapolation. In this work, PBPK models were developed for adult male and female rats to describe the pharmacokinetics of PFOA and PFOS. The models contain a description of saturable renal resorption, free fraction of chemical in plasma, and saturable binding in liver. Both male and female rat models for each chemical were consistent with available PK data resulting from IV, oral, and dietary dosing regimens. Predicted plasma concentration curves followed trends observed in experimental data, and model predictions were within a factor of two of experimental values. PFOA and PFOS rat model output is sensitive to parameters governing renal resorption, indicating that renal resorption is responsible for the long-half life. These models, along with the PFAA gestation and lactation models published in this issue, will help address concerns about possible health effects due to PFAA exposure in the fetus and neonate and will be useful in comparing PK across life stages.
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Affiliation(s)
- Anne E Loccisano
- Center for Human Health Assessment, The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC 27709, United States.
| | - Jerry L Campbell
- Center for Human Health Assessment, The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC 27709, United States
| | - John L Butenhoff
- 3M Medical Department, Corporate Toxicology, 3M Center 220-2E-02, St. Paul, MN 55144, United States
| | - Melvin E Andersen
- Center for Human Health Assessment, The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC 27709, United States
| | - Harvey J Clewell
- Center for Human Health Assessment, The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC 27709, United States
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Study of the performance of three LC-MS/MS platforms for analysis of perfluorinated compounds. Anal Bioanal Chem 2010; 398:1145-59. [DOI: 10.1007/s00216-010-3911-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 06/05/2010] [Accepted: 06/08/2010] [Indexed: 11/26/2022]
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Klaassen CD, Aleksunes LM. Xenobiotic, bile acid, and cholesterol transporters: function and regulation. Pharmacol Rev 2010; 62:1-96. [PMID: 20103563 PMCID: PMC2835398 DOI: 10.1124/pr.109.002014] [Citation(s) in RCA: 561] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting beta polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) alpha and beta] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of regulatory factors that influence transporter expression and function, including transcriptional activation and post-translational modifications as well as subcellular trafficking. Sex differences, ontogeny, and pharmacological and toxicological regulation of transporters are also addressed. Transporters are important transmembrane proteins that mediate the cellular entry and exit of a wide range of substrates throughout the body and thereby play important roles in human physiology, pharmacology, pathology, and toxicology.
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Affiliation(s)
- Curtis D Klaassen
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160-7417, USA.
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Kay HY, Wu H, Lee SI, Kim SG. Applications of genetically modified tools to safety assessment in drug development. Toxicol Res 2010; 26:1-8. [PMID: 24278499 PMCID: PMC3834461 DOI: 10.5487/tr.2010.26.1.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 01/26/2010] [Accepted: 01/26/2010] [Indexed: 02/01/2023] Open
Abstract
The process of new drug development consists of several stages; after identifying potential candidate compounds, preclinical studies using animal models link the laboratory and human clinical trials. Among many steps in preclinical studies, toxicology and safety assessments contribute to identify potential adverse events and provide rationale for setting the initial doses in clinical trials. Gene modulation is one of the important tools of modern biology, and is commonly employed to examine the function of genes of interest. Advances in new drug development have been achieved by exploding information on target selection and validation using genetically modified animal models as well as those of cells. In this review, a recent trend of genetically modified methods is discussed with reference to safety assessments, and the exemplary applications of gene-modulating tools to the tests in new drug development were summarized.
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Affiliation(s)
- Hee Yeon Kay
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University
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MINATA M, HARADA KH, KÄRRMAN A, HITOMI T, HIROSAWA M, MURATA M, GONZALEZ FJ, KOIZUMI A. Role of peroxisome proliferator-activated receptor-alpha in hepatobiliary injury induced by ammonium perfluorooctanoate in mouse liver. INDUSTRIAL HEALTH 2010; 48:96-107. [PMID: 20160413 PMCID: PMC7385711 DOI: 10.2486/indhealth.48.96] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Peroxisome proliferator-activated receptor-alpha (PPARalpha) has been suggested to protect against chemically induced hepatobiliary injuries in rodents. This function could mask the potential toxicities of perfluorooctanoic acid (PFOA) that is an emerging environmental contaminant and a weak ligand of PPARalpha. However its function has not been clarified. In this study, PFOA was found to elicit hepatocyte and bile duct injuries in Pparalpha-null mice after 4 wk treatment with PFOA ammonium salt (0, 12.5, 25, 50 micromol/kg/d, gavage). In wild-type mice, PFOA caused major hepatocellular damage dose-dependently and minor cholangiopathy observed only at 25 and 50 micromol/kg. In treated Pparalpha-null mice, PFOA produced marked fat accumulation, severe cholangiopathy, hepatocellular damage and apoptotic cells especially in bile ducts. Oxidative stress was also increased 4-fold at 50 micromol/kg and TNF-alpha mRNA was upregulated more than 3-fold at 25 micromol/kg in Pparalpha-null mice. Biliary bile acid/phospholipid ratios were higher in Pparalpha-null mice than in wild-type mice. Results from these studies suggest that PPARalpha is protective against PFOA and have a critical role in drug induced hepatobiliary injury.
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Affiliation(s)
- Mutsuko MINATA
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Kouji H. HARADA
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Anna KÄRRMAN
- MTM Research Centre, Örebro University, Örebro 70182, Sweden
| | - Toshiaki HITOMI
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Michi HIROSAWA
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Mariko MURATA
- Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514-8507, Japan
| | - Frank J. GONZALEZ
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Akio KOIZUMI
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
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Ren H, Aleksunes LM, Wood C, Vallanat B, George MH, Klaassen CD, Corton JC. Characterization of peroxisome proliferator-activated receptor alpha--independent effects of PPARalpha activators in the rodent liver: di-(2-ethylhexyl) phthalate also activates the constitutive-activated receptor. Toxicol Sci 2009; 113:45-59. [PMID: 19850644 DOI: 10.1093/toxsci/kfp251] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Peroxisome proliferator chemicals (PPC) are thought to mediate their effects in rodents on hepatocyte growth and liver cancer through the nuclear receptor peroxisome proliferator-activated receptor (PPAR) alpha. Recent studies indicate that the plasticizer di-(2-ethylhexyl) phthalate (DEHP) increased the incidence of liver tumors in PPARalpha-null mice. We hypothesized that some PPC, including DEHP, induce transcriptional changes independent of PPARalpha but dependent on other nuclear receptors, including the constitutive-activated receptor (CAR) that mediates phenobarbital (PB) effects on hepatocyte growth and liver tumor induction. To determine the potential role of CAR in mediating effects of PPC, a meta-analysis was performed on transcript profiles from published studies in which rats and mice were exposed to PPC and compared the profiles to those produced by exposure to PB. Valproic acid, clofibrate, and DEHP in rat liver and DEHP in mouse liver induced genes, including Cyp2b family members that are known to be regulated by CAR. Examination of transcript changes by Affymetrix ST 1.0 arrays and reverse transcription-PCR in the livers of DEHP-treated wild-type, PPARalpha-null, and CAR-null mice demonstrated that (1) most (approximately 94%) of the transcriptional changes induced by DEHP were PPARalpha-dependent, (2) many PPARalpha-independent genes overlapped with those regulated by PB, (3) induction of genes Cyp2b10, Cyp3a11, and metallothionine-1 by DEHP was CAR dependent but PPARalpha-independent, and (4) induction of a number of genes (Cyp8b1, Gstm4, and Gstm7) was independent of both CAR and PPARalpha. Our results indicate that exposure to PPARalpha activators including DEHP leads to activation of multiple nuclear receptors in the rodent liver.
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Affiliation(s)
- Hongzu Ren
- National Health and Environmental Effects Research Lab Toxicogenomics Core, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
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Csanaky IL, Aleksunes LM, Tanaka Y, Klaassen CD. Role of hepatic transporters in prevention of bile acid toxicity after partial hepatectomy in mice. Am J Physiol Gastrointest Liver Physiol 2009; 297:G419-33. [PMID: 19497955 PMCID: PMC2739828 DOI: 10.1152/ajpgi.90728.2008] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The enterohepatic recirculation of bile acids (BAs) is important in several physiological processes. Although there has been considerable research on liver regeneration after two-thirds partial hepatectomy (PHx), little is known about how the liver protects itself against BA toxicity during regeneration. In this study, various BAs in plasma and liver, the composition of micelle-forming bile constituents, as well as gene expression of the main hepatobiliary transporters were quantified in sham-operated and PHx mice 24 and 48 h after surgery. PHx did not influence the hepatic concentrations of taurine-conjugated BAs (T-BA) but increased the concentration of glycine-conjugated (G-BA) and unconjugated BAs. Total BA excretion (microg x min(-1) x g liver wt(-1)) increased 2.4-fold and was accompanied by a 55% increase in bile flow after PHx. The plasma concentrations of T-BAs (402-fold), G-BAs (17-fold), and unconjugated BAs (500-fold) increased. The mRNA and protein levels of the BA uptake transporter Ntcp were unchanged after PHx, whereas the canalicular Bsep protein increased twofold at 48 h. The basolateral efflux transporter Mrp3 was induced at the mRNA (2.6-fold) and protein (3.1-fold) levels after PHx, which may contribute to elevated plasma BA and bilirubin levels. Biliary phospholipid excretion was nearly doubled in PHx mice, most likely owing to increased mRNA expression of the phospholipid transporter, Mdr2. In conclusion, the remnant liver after PHx excretes 2.5-fold more BAs and three times more phospholipids per gram liver than the sham-operated mouse liver. Upregulation of phospholipid transport may be important in protecting the biliary tract from BA toxicity during PHx.
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Affiliation(s)
- Iván L. Csanaky
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Lauren M. Aleksunes
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Yuji Tanaka
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Curtis D. Klaassen
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
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48
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Regulation of bile acid and cholesterol metabolism by PPARs. PPAR Res 2009; 2009:501739. [PMID: 19636418 PMCID: PMC2712638 DOI: 10.1155/2009/501739] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 05/15/2009] [Indexed: 01/27/2023] Open
Abstract
Bile acids are amphipathic molecules synthesized from cholesterol in the liver. Bile acid synthesis is a major pathway for hepatic cholesterol catabolism. Bile acid synthesis generates bile flow which is important for biliary secretion of free cholesterol, endogenous metabolites, and xenobiotics. Bile acids are biological detergents that facilitate intestinal absorption of lipids and fat-soluble vitamins. Recent studies suggest that bile acids are important metabolic regulators of lipid, glucose, and energy homeostasis. Agonists of peroxisome proliferator-activated receptors (PPARα, PPARγ, PPARδ) regulate lipoprotein metabolism, fatty acid oxidation, glucose homeostasis and inflammation, and therefore are
used as anti-diabetic drugs for treatment of dyslipidemia and insulin insistence. Recent studies have shown that activation of
PPARα alters bile acid synthesis, conjugation, and transport, and also cholesterol synthesis, absorption and reverse cholesterol transport. This review will focus on the roles of PPARs in the regulation of pathways in bile acid and cholesterol homeostasis, and the therapeutic implications of using PPAR agonists for the treatment of metabolic syndrome.
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49
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Foreman JE, Chang SC, Ehresman DJ, Butenhoff JL, Anderson CR, Palkar PS, Kang BH, Gonzalez FJ, Peters JM. Differential hepatic effects of perfluorobutyrate mediated by mouse and human PPAR-alpha. Toxicol Sci 2009; 110:204-11. [PMID: 19359353 DOI: 10.1093/toxsci/kfp077] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Perfluorobutyrate (PFBA) is a short chain perfluoroalkyl carboxylate that is structurally similar to perfluorooctanoate. Administration of PFBA can cause peroxisome proliferation, induction of peroxisomal fatty acid oxidation and hepatomegaly, suggesting that PFBA activates the nuclear receptor, peroxisome proliferator-activated receptor-alpha (PPAR-alpha). In this study, the role of PPAR-alpha in mediating the effects of PFBA was examined using PPAR-alpha null mice and a mouse line expressing the human PPAR-alpha in the absence of mouse PPAR-alpha (PPAR-alpha humanized mice). PFBA caused upregulation of known PPAR-alpha target genes that modulate lipid metabolism in wild-type and PPAR-alpha humanized mice, and this effect was not found in PPAR-alpha null mice. Increased liver weight and hepatocyte hypertrophy were also found in wild-type and humanized PPAR-alpha mice treated with PFBA, but not in PPAR-alpha null mice. Interestingly, hepatocyte focal necrosis with inflammatory cell infiltrate was only found in wild-type mice administered PFBA; this effect was markedly diminished in both PPAR-alpha null and PPAR-alpha humanized mice. Results from these studies demonstrate that PFBA can modulate gene expression and cause mild hepatomegaly and hepatocyte hypertrophy through a mechanism that requires PPAR-alpha and that these effects do not exhibit a species difference. In contrast, the PPAR-alpha-dependent increase in PFBA-induced hepatocyte focal necrosis with inflammatory cell infiltrate was mediated by the mouse PPAR-alpha but not the human PPAR-alpha. Collectively, these findings demonstrate that PFBA can activate both the mouse and human PPAR-alpha, but there is a species difference in the hepatotoxic response to this chemical.
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Affiliation(s)
- Jennifer E Foreman
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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50
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Evidence for the involvement of xenobiotic-responsive nuclear receptors in transcriptional effects upon perfluoroalkyl acid exposure in diverse species. Reprod Toxicol 2009; 27:266-277. [PMID: 19162173 DOI: 10.1016/j.reprotox.2008.12.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 12/12/2008] [Accepted: 12/22/2008] [Indexed: 12/18/2022]
Abstract
Humans and ecological species have been found to have detectable body burdens of a number of perfluorinated alkyl acids (PFAA) including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). In mouse and rat liver these compounds elicit transcriptional and phenotypic effects similar to peroxisome proliferator chemicals (PPC) that work through the nuclear receptor peroxisome proliferator-activated receptor alpha (PPAR alpha). Recent studies indicate that along with PPAR alpha other nuclear receptors are required for transcriptional changes in the mouse liver after PFOA exposure including the constitutive activated receptor (CAR) and pregnane X receptor (PXR) that regulate xenobiotic metabolizing enzymes (XME). To determine the potential role of CAR/PXR in mediating effects of PFAAs in rat liver, we performed a meta-analysis of transcript profiles from published studies in which rats were exposed to PFOA or PFOS. We compared the profiles to those produced by exposure to prototypical activators of CAR, (phenobarbital (PB)), PXR (pregnenolone 16 alpha-carbonitrile (PCN)), or PPAR alpha (WY-14,643 (WY)). As expected, PFOA and PFOS elicited transcript profile signatures that included many known PPAR alpha target genes. Numerous XME genes were also altered by PFOA and PFOS but not WY. These genes exhibited expression changes shared with PB or PCN. Reexamination of the transcript profiles from the livers of chicken or fish exposed to PFAAs indicated that PPAR alpha, CAR, and PXR orthologs were not activated. Our results indicate that PFAAs under these experimental conditions activate PPAR alpha, CAR, and PXR in rats but not chicken and fish. Lastly, we discuss evidence that human populations with greater CAR expression have lower body burdens of PFAAs.
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