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Cholico GN, Fling RR, Sink WJ, Nault R, Zacharewski T. Inhibition of the urea cycle by the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin increases serum ammonia levels in mice. J Biol Chem 2024; 300:105500. [PMID: 38013089 PMCID: PMC10731612 DOI: 10.1016/j.jbc.2023.105500] [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: 08/29/2023] [Revised: 10/26/2023] [Accepted: 11/18/2023] [Indexed: 11/29/2023] Open
Abstract
The aryl hydrocarbon receptor is a ligand-activated transcription factor known for mediating the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. TCDD induces nonalcoholic fatty liver disease (NAFLD)-like pathologies including simple steatosis that can progress to steatohepatitis with fibrosis and bile duct proliferation in male mice. Dose-dependent progression of steatosis to steatohepatitis with fibrosis by TCDD has been associated with metabolic reprogramming, including the disruption of amino acid metabolism. Here, we used targeted metabolomic analysis to reveal dose-dependent changes in the level of ten serum and eleven hepatic amino acids in mice upon treatment with TCDD. Bulk RNA-seq and protein analysis showed TCDD repressed CPS1, OTS, ASS1, ASL, and GLUL, all of which are associated with the urea cycle and glutamine biosynthesis. Urea and glutamine are end products of the detoxification and excretion of ammonia, a toxic byproduct of amino acid catabolism. Furthermore, we found that the catalytic activity of OTC, a rate-limiting step in the urea cycle was also dose dependently repressed. These results are consistent with an increase in circulating ammonia. Collectively, the repression of the urea and glutamate-glutamine cycles increased circulating ammonia levels and the toxicity of TCDD.
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Affiliation(s)
- Giovan N Cholico
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA; Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Russell R Fling
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA; Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Warren J Sink
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA; Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Rance Nault
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA; Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Tim Zacharewski
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA; Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA.
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2
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Kumbale CM, Zhang Q, Voit EO. Hepatic cholesterol biosynthesis and dioxin-induced dysregulation: A multiscale computational approach. Food Chem Toxicol 2023; 181:114086. [PMID: 37820785 PMCID: PMC10841405 DOI: 10.1016/j.fct.2023.114086] [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: 05/25/2023] [Revised: 09/18/2023] [Accepted: 10/03/2023] [Indexed: 10/13/2023]
Abstract
Humans are constantly exposed to lipophilic persistent organic pollutants (POPs) that accumulate in fatty foods. Among the numerous POPs, dioxins, in particular 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), can impact several organ systems. While the hazard is clearly recognized, it is still difficult to develop a comprehensive understanding of the overall health impacts of dioxins. As chemical toxicity testing is steadily adopting new approach methodologies (NAMs), it becomes imperative to develop computational models that can bridge the data gaps between in vitro testing and in vivo outcomes. As an effort to address this challenge, we propose a multiscale computational approach using a "template-and-anchor" (T&A) structure. A template is a high-level umbrella model that permits the integration of information from various, detailed anchor models. In the present study, we use this T&A approach to describe the effect of TCDD on cholesterol dynamics. Specifically, we represent hepatic cholesterol biosynthesis as an anchor model that is perturbed by TCDD, leading to steatosis, along with alterations of plasma cholesterol. In the future, incorporating pertinent information from all anchor models into the template model will allow the characterization of the global effects of dioxin, which can subsequently be translated into overall - and ultimately personalized - human health risk assessment.
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Affiliation(s)
- Carla M Kumbale
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
| | - Eberhard O Voit
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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3
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Jurgelewicz A, Nault R, Harkema J, Zacharewski TR, LaPres JJ. Characterizing the impact of simvastatin co-treatment of cell specific TCDD-induced gene expression and systemic toxicity. Sci Rep 2023; 13:16598. [PMID: 37789023 PMCID: PMC10547718 DOI: 10.1038/s41598-023-42972-8] [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: 09/15/2022] [Accepted: 09/17/2023] [Indexed: 10/05/2023] Open
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is associated with metabolic syndrome (MetS) in humans and elicits pathologies in rodents that resemble non-alcoholic fatty liver disease (NAFLD) in humans through activation of the aryl hydrocarbon receptor (AHR) pathway. Dysregulation of cholesterol homeostasis, an aspect of MetS, is linked to NAFLD pathogenesis. TCDD exposure is also linked to the suppression of genes that encode key cholesterol biosynthesis steps and changes in serum cholesterol levels. In a previous experiment, treating mice with TCDD in the presence of simvastatin, a 3-Hydroxy-3-Methylglutaryl-CoA Reductase competitive inhibitor, altered lipid and glycogen levels, AHR-battery gene expression, and liver injury in male mice compared to TCDD alone. The aim of this study was to deduce a possible mechanism(s) for the metabolic changes and increased injury using single-nuclei RNA sequencing in mouse liver. We demonstrated that co-treated mice experienced wasting and increased AHR activation compared to TCDD alone. Furthermore, relative proportions of cell (sub)types were different between TCDD alone and co-treated mice including important mediators of NAFLD progression like hepatocytes and immune cell populations. Analysis of non-overlapping differentially expressed genes identified several pathways where simvastatin co-treatment significantly impacted TCDD-induced changes, which may explain the differences between treatments. Overall, these results demonstrate a connection between dysregulation of cholesterol homeostasis and toxicant-induced metabolic changes.
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Affiliation(s)
- Amanda Jurgelewicz
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
- Institute for Integrative Toxicological Sciences, Michigan State University, East Lansing, MI, USA
| | - Rance Nault
- Institute for Integrative Toxicological Sciences, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, 602 Wilson Rd, East Lansing, MI, 48824, USA
| | - Jack Harkema
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI, USA
| | - Timothy R Zacharewski
- Institute for Integrative Toxicological Sciences, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, 602 Wilson Rd, East Lansing, MI, 48824, USA
| | - John J LaPres
- Institute for Integrative Toxicological Sciences, Michigan State University, East Lansing, MI, USA.
- Department of Biochemistry and Molecular Biology, Michigan State University, 602 Wilson Rd, East Lansing, MI, 48824, USA.
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4
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Hammoudeh N, Soukkarieh C, Murphy DJ, Hanano A. Female-to-male differential transcription patterns of miRNA-mRNA networks in the livers of dioxin-exposed mice. ENVIRONMENTAL TOXICOLOGY 2023; 38:2310-2331. [PMID: 37318321 DOI: 10.1002/tox.23868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/14/2023] [Accepted: 06/05/2023] [Indexed: 06/16/2023]
Abstract
Non-coding microRNAs (miRNAs) have important roles in regulating the expression of liver mRNAs in response to xenobiotic-exposure, but their roles concerning dioxins such as TCDD (2,3,7,8-Tetrachlorodibenzo-p-dioxin) are less clear. This report concerns the potential implication of liver (class I) and circulating (class II) miRNAs in hepatotoxicity of female and male mice after acute exposure to TCDD. The data show that, of a total of 38 types of miRNAs, the expression of eight miRNAs were upregulated in both female and male mice exposed to TCDD. Inversely, the expression of nine miRNAs were significantly downregulated in both animal genders. Moreover, certain miRNAs were preferentially induced in either females or males. The potential downstream regulatory effects of miRNAs on their target genes was evaluated by determining the expression of three group of genes that are potentially involved in cancer biogenesis, other diseases and in hepatotoxicity. It was found that certain cancer-related genes were more highly expressed females rather than males after exposure to TCDD. Furthermore, a paradoxical female-to-male transcriptional pattern was found for several disease-related and hepatotoxicity-related genes. These results suggest the possibility of developing of new miRNA-specific interfering molecules to address their dysfunctions as caused by TCDD.
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Affiliation(s)
- Nour Hammoudeh
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Chadi Soukkarieh
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Denis J Murphy
- School of Applied Sciences, University of South Wales, Pontypridd, UK
| | - Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), Damascus, Syria
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5
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Faiad W, Soukkarieh C, Hanano A. 2,3,7,8-tetrachlorodibenzo-p-dioxin induces multigenerational testicular toxicity and biosynthetic disorder of testosterone in BALB/C mice: Transcriptional, histopathological and hormonal determinants. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 263:115233. [PMID: 37421896 DOI: 10.1016/j.ecoenv.2023.115233] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 06/30/2023] [Accepted: 07/04/2023] [Indexed: 07/10/2023]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent environmental contaminant, is an endocrine disrupter with a proven reproductive toxicity in mammals. However, its effects on male fertility across generations are still elusive. The current work evaluates the toxicity of dioxin on male reproductive system in two separate groups of BALB/C mice; a group of pubertal males directly exposed to TCDD (referred to as DEmG), and a group of indirectly exposed males (referred to as IDEmG) comprises of F1, F2 and F3 males born from TCDD-exposed pregnant females. Both groups were exposed to 25 μg TCDD/kg body weight for a week. Our data show that males of TCDD-DEmG exhibited significant alterations in the expression of certain genes involved in the detoxification of TCDD and the biosynthesis of testosterone. This was accompanied with testicular pathological symptoms, including a sloughing in the germinal epithelium and a congestion of blood vessels in interstitial tissue with the presence of multinuclear cells into seminiferous tubule, with a 4-fold decline in the level of serum testosterone and reduced sperm count. Otherwise, the male reproductive toxicity across F1, F2 and F3 generations from TCDD-IDEmG was mainly characterized by: i) a reduce in body and testis weight. ii) a decrease in gene expression of steriodogenesis enzyme, e.g., AhR, CYP1A1, CYP11A1, COX1, COX2, LOX5 and LOX12. iii) a remarked and similar testicular histopathology that found for DEmG, iv) a serious decline in serum testosterone. v) a decreased male-to-female ratio. vi) a low sperm count with increasing abnormalities. Thus, pubertal or maternal exposure to TCDD provokes multigenerational male reproductive toxicity in mice, ultimately affecting the spermatogenesis and suggesting that the hormonal alternation and sperm abnormality are the most marked effects of the indirect exposure of mammalian male to TCDD.
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Affiliation(s)
- Walaa Faiad
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Chadi Soukkarieh
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), Damascus, Syria.
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Badawy AB. The kynurenine pathway of tryptophan metabolism: a neglected therapeutic target of COVID-19 pathophysiology and immunotherapy. Biosci Rep 2023; 43:BSR20230595. [PMID: 37486805 PMCID: PMC10407158 DOI: 10.1042/bsr20230595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/29/2023] [Accepted: 07/21/2023] [Indexed: 07/26/2023] Open
Abstract
SARS-CoV-2 (COVID-19) exerts profound changes in the kynurenine (Kyn) pathway (KP) of tryptophan (Trp) metabolism that may underpin its pathophysiology. The KP is the main source of the vital cellular effector NAD+ and intermediate metabolites that modulate immune and neuronal functions. Trp metabolism is the top pathway influenced by COVID-19. Sixteen studies established virus-induced activation of the KP mediated mainly by induction of indoleamine 2,3-dioxygenase (IDO1) in most affected tissues and of IDO2 in lung by the increased release of proinflammatory cytokines but could additionally involve increased flux of plasma free Trp and induction of Trp 2,3-dioxygenase (TDO) by cortisol. The major Kyn metabolite targeted by COVID-19 is kynurenic acid (KA), the Kyn metabolite with the greatest affinity for the aryl hydrocarbon receptor (AhR), which is also activated by COVID-19. AhR activation initiates two important series of events: a vicious circle involving IDO1 induction, KA accumulation and further AhR activation, and activation of poly (ADP-ribose) polymerase (PARP) leading to NAD+ depletion and cell death. The virus further deprives the host of NAD+ by inhibiting its main biosynthetic pathway from quinolinic acid, while simultaneously acquiring NAD+ by promoting its synthesis from nicotinamide in the salvage pathway. Additionally, the protective effects of sirtuin 1 are minimised by the PARP activation. KP dysfunction may also underpin the mood and neurological disorders acutely and during 'long COVID'. More studies of potential effects of vaccination therapy on the KP are required and exploration of therapeutic strategies involving modulation of the KP changes are proposed.
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Affiliation(s)
- Abdulla Abu-Bakr Badawy
- Formerly School of Health Sciences, Cardiff Metropolitan University, Western Avenue, Cardiff CF5 2YB, Wales, U.K
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7
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Orlowska K, Fling RR, Nault R, Schilmiller AL, Zacharewski TR. Cystine/Glutamate Xc - Antiporter Induction Compensates for Transsulfuration Pathway Repression by 2,3,7,8-Tetrachlorodibenzo- p-dioxin (TCDD) to Ensure Cysteine for Hepatic Glutathione Biosynthesis. Chem Res Toxicol 2023; 36:900-915. [PMID: 37184393 PMCID: PMC10284067 DOI: 10.1021/acs.chemrestox.3c00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Indexed: 05/16/2023]
Abstract
Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been associated with the induction of oxidative stress and the progression of steatosis to steatohepatitis with fibrosis. It also disrupts metabolic pathways including one-carbon metabolism (OCM) and the transsulfuration pathway with possible consequences on glutathione (GSH) levels. In this study, complementary RNAseq and metabolomics data were integrated to examine the hepatic transsulfuration pathway and glutathione biosynthesis in mice following treatment with TCDD every 4 days for 28 days. TCDD dose-dependently repressed hepatic cystathionine β-synthase (CBS) and cystathionine γ-lyase (CTH) mRNA and protein levels. Reduced CBS and CTH levels are also correlated with dose-dependent decreases in hepatic extract hydrogen sulfide (H2S). In contrast, cysteine levels increased consistent with the induction of Slc7a11, which encodes for the cystine/glutamate Xc- antiporter. Cotreatment of primary hepatocytes with sulfasalazine, a cystine/glutamate Xc- antiporter inhibitor, decreased labeled cysteine incorporation into GSH with a corresponding increase in TCDD cytotoxicity. Although reduced and oxidized GSH levels were unchanged following treatment due to the induction of GSH/GSSG efflux transporter by TCDD, the GSH:GSSG ratio decreased and global protein S-glutathionylation levels in liver extracts increased in response to oxidative stress along with the induction of glutamate-cysteine ligase catalytic subunit (Gclc), glutathione synthetase (Gss), glutathione disulfide reductase (Gsr), and glutathione transferase π (Gstp). Furthermore, levels of ophthalmic acid, a biomarker of oxidative stress indicating GSH consumption, were also increased. Collectively, the data suggest that increased cystine transport due to cystine/glutamate Xc- antiporter induction compensated for decreased cysteine production following repression of the transsulfuration pathway to support GSH synthesis in response to TCDD-induced oxidative stress.
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Affiliation(s)
- Karina Orlowska
- Biochemistry
& Molecular Biology, Institute for Integrative Toxicology, Microbiology &
Molecular Genetics, and Mass Spectrometry and Metabolomics Core, Michigan State University, East Lansing, Michigan 48824, United States
| | - Russ R. Fling
- Biochemistry
& Molecular Biology, Institute for Integrative Toxicology, Microbiology &
Molecular Genetics, and Mass Spectrometry and Metabolomics Core, Michigan State University, East Lansing, Michigan 48824, United States
| | - Rance Nault
- Biochemistry
& Molecular Biology, Institute for Integrative Toxicology, Microbiology &
Molecular Genetics, and Mass Spectrometry and Metabolomics Core, Michigan State University, East Lansing, Michigan 48824, United States
| | - Anthony L. Schilmiller
- Biochemistry
& Molecular Biology, Institute for Integrative Toxicology, Microbiology &
Molecular Genetics, and Mass Spectrometry and Metabolomics Core, Michigan State University, East Lansing, Michigan 48824, United States
| | - Timothy R. Zacharewski
- Biochemistry
& Molecular Biology, Institute for Integrative Toxicology, Microbiology &
Molecular Genetics, and Mass Spectrometry and Metabolomics Core, Michigan State University, East Lansing, Michigan 48824, United States
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8
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Dolce A, Della Torre S. Sex, Nutrition, and NAFLD: Relevance of Environmental Pollution. Nutrients 2023; 15:nu15102335. [PMID: 37242221 DOI: 10.3390/nu15102335] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/12/2023] [Accepted: 05/13/2023] [Indexed: 05/28/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease and represents an increasing public health issue given the limited treatment options and its association with several other metabolic and inflammatory disorders. The epidemic, still growing prevalence of NAFLD worldwide cannot be merely explained by changes in diet and lifestyle that occurred in the last few decades, nor from their association with genetic and epigenetic risk factors. It is conceivable that environmental pollutants, which act as endocrine and metabolic disruptors, may contribute to the spreading of this pathology due to their ability to enter the food chain and be ingested through contaminated food and water. Given the strict interplay between nutrients and the regulation of hepatic metabolism and reproductive functions in females, pollutant-induced metabolic dysfunctions may be of particular relevance for the female liver, dampening sex differences in NAFLD prevalence. Dietary intake of environmental pollutants can be particularly detrimental during gestation, when endocrine-disrupting chemicals may interfere with the programming of liver metabolism, accounting for the developmental origin of NAFLD in offspring. This review summarizes cause-effect evidence between environmental pollutants and increased incidence of NAFLD and emphasizes the need for further studies in this field.
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Affiliation(s)
- Arianna Dolce
- Department of Pharmaceutical Sciences, University of Milan, 20133 Milan, Italy
| | - Sara Della Torre
- Department of Pharmaceutical Sciences, University of Milan, 20133 Milan, Italy
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Aldeli N, Soukkarie C, Hanano A. Transcriptional, hormonal and histological alterations in the ovaries of BALB/c mice exposed to TCDD in connection with multigenerational female infertility. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 258:114990. [PMID: 37156038 DOI: 10.1016/j.ecoenv.2023.114990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener of dioxins, has a proven reproductive toxicity. Due to the lack of evidence on the multigenerational female reproductive toxicity of TCDD through the maternal exposure, the current study aims to evaluate, on the one hand, the acute reproductive toxicity of TCDD on adult female pre-gestational exposed to a critical single dose of TCDD (25 μg/kg) for a week (group referred to as AFnG; adult female/non-gestation). On the other hand, the transcription, hormonal and histological effects of TCDD on the females of two generations F1 and F2, were also investigated after the exposure of pregnant females to TCDD on gestational day 13 (GD13) (group referred to as AFG; adult female/gestation). First, our data showed alternations in the ovarian expressional pattern of certain key genes involved in the detoxification of TCDD as well as in the biosynthesis of steroidal hormones. The expression of Cyp1a1 was highly induced in TCDD-AFnG group, but reduced in both F1 and F2. While the transcripts levels of Cyp11a1 and 3βhsd2 were decreased, Cyp19a1 transcripts were increased as a function of TCDD exposure. This was synchronized with a dramatic increase in the level of estradiol hormone in the females of both experimental groups. Beside a significant reduce in their size and weight, ovaries of TCDD-exposed females showed serious histological alterations marked by atrophy of the ovary, congestion in the blood vessels, necrosis in the layer of granular cells, dissolution of the oocyte and nucleus of ovarian follicles. Finally, the female fertility was dramatically affected across generations with a reduced male\female ratio. Our data indicate that the exposure of pregnant female to TCDD has serious negative effects in the female productive system across generations and suggest the use of hormonal alternation as biomarker to monitor and assess the indirect exposure of these generations to TCDD.
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Affiliation(s)
- Nour Aldeli
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Chadi Soukkarie
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), Damascus, Syria.
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10
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Zhou W, Shi W, Du X, Han Y, Tang Y, Ri S, Ju K, Kim T, Huang L, Zhang W, Yu Y, Tian D, Yu Y, Chen L, Wu Z, Liu G. Assessment of Nonalcoholic Fatty Liver Disease Symptoms and Gut-Liver Axis Status in Zebrafish after Exposure to Polystyrene Microplastics and Oxytetracycline, Alone and in Combination. ENVIRONMENTAL HEALTH PERSPECTIVES 2023; 131:47006. [PMID: 37027337 PMCID: PMC10081693 DOI: 10.1289/ehp11600] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/31/2022] [Accepted: 02/23/2023] [Indexed: 05/19/2023]
Abstract
BACKGROUND Environmental pollution may give rise to the incidence and progression of nonalcoholic fatty liver disease (NAFLD), the most common cause for chronic severe liver lesions. Although knowledge of NAFLD pathogenesis is particularly important for the development of effective prevention, the relationship between NAFLD occurrence and exposure to emerging pollutants, such as microplastics (MPs) and antibiotic residues, awaits assessment. OBJECTIVES This study aimed to evaluate the toxicity of MPs and antibiotic residues related to NAFLD occurrence using the zebrafish model species. METHODS Taking common polystyrene MPs and oxytetracycline (OTC) as representatives, typical NAFLD symptoms, including lipid accumulation, liver inflammation, and hepatic oxidative stress, were screened after 28-d exposure to environmentally realistic concentrations of MPs (0.69mg/L) and antibiotic residue (3.00μg/L). The impacts of MPs and OTC on gut health, the gut-liver axis, and hepatic lipid metabolism were also investigated to reveal potential affecting mechanisms underpinning the NAFLD symptoms observed. RESULTS Compared with the control fish, zebrafish exposed to MPs and OTC exhibited significantly higher levels of lipid accumulation, triglycerides, and cholesterol contents, as well as inflammation, in conjunction with oxidative stress in their livers. In addition, a markedly smaller proportion of Proteobacteria and higher ratios of Firmicutes/Bacteroidetes were detected by microbiome analysis of gut contents in treated samples. After the exposures, the zebrafish also experienced intestinal oxidative injury and yielded significantly fewer numbers of goblet cells. Markedly higher levels of the intestinal bacteria-sourced endotoxin lipopolysaccharide (LPS) were also detected in serum. Animals treated with MPs and OTC exhibited higher expression levels of LPS binding receptor (LBP) and downstream inflammation-related genes while also exhibiting lower activity and gene expression of lipase. Furthermore, MP-OTC coexposure generally exerted more severe effects compared with single MP or OTC exposure. DISCUSSION Our results suggested that exposure to MPs and OTC may disrupt the gut-liver axis and be associated with NAFLD occurrence. https://doi.org/10.1289/EHP11600.
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Affiliation(s)
- Weishang Zhou
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Wei Shi
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Xueying Du
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Yu Han
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Yu Tang
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Sanghyok Ri
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
- College of Life Science, Kim Hyong Jik University of Education, Pyongyang, DPR Korea
| | - Kwangjin Ju
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
- College of Aquaculture, Wonsan Fisheries University, Wonsan, DPR Korea
| | - Tongchol Kim
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
- College of Life Science, Kim Hyong Jik University of Education, Pyongyang, DPR Korea
| | - Lin Huang
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Weixia Zhang
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Yihan Yu
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Dandan Tian
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Yingying Yu
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Liangbiao Chen
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, P.R. China
| | - Zhichao Wu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, P.R. China
| | - Guangxu Liu
- College of Animal Sciences, Zhejiang University, Hangzhou, P.R. China
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11
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Cholico GN, Orlowska K, Fling RR, Sink WJ, Zacharewski NA, Fader KA, Nault R, Zacharewski T. Consequences of reprogramming acetyl-CoA metabolism by 2,3,7,8-tetrachlorodibenzo-p-dioxin in the mouse liver. Sci Rep 2023; 13:4138. [PMID: 36914879 PMCID: PMC10011583 DOI: 10.1038/s41598-023-31087-9] [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: 08/30/2022] [Accepted: 03/06/2023] [Indexed: 03/14/2023] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant that induces the progression of steatosis to steatohepatitis with fibrosis in mice. Furthermore, TCDD reprograms hepatic metabolism by redirecting glycolytic intermediates while inhibiting lipid metabolism. Here, we examined the effect of TCDD on hepatic acetyl-coenzyme A (acetyl-CoA) and β-hydroxybutyrate levels as well as protein acetylation and β-hydroxybutyrylation. Acetyl-CoA is not only a central metabolite in multiple anabolic and catabolic pathways, but also a substrate used for posttranslational modification of proteins and a surrogate indicator of cellular energy status. Targeted metabolomic analysis revealed a dose-dependent decrease in hepatic acetyl-CoA levels coincident with the phosphorylation of pyruvate dehydrogenase (E1), and the induction of pyruvate dehydrogenase kinase 4 and pyruvate dehydrogenase phosphatase, while repressing ATP citrate lyase and short-chain acyl-CoA synthetase gene expression. In addition, TCDD dose-dependently reduced the levels of hepatic β-hydroxybutyrate and repressed ketone body biosynthesis gene expression. Moreover, levels of total hepatic protein acetylation and β-hydroxybutyrylation were reduced. AMPK phosphorylation was induced consistent with acetyl-CoA serving as a cellular energy status surrogate, yet subsequent targets associated with re-establishing energy homeostasis were not activated. Collectively, TCDD reduced hepatic acetyl-CoA and β-hydroxybutyrate levels eliciting starvation-like conditions despite normal levels of food intake.
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Affiliation(s)
- Giovan N Cholico
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Karina Orlowska
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Russell R Fling
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
- Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Warren J Sink
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Nicholas A Zacharewski
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
| | - Kelly A Fader
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Rance Nault
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Tim Zacharewski
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA.
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA.
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12
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Inhibition of Aryl Hydrocarbon Receptor (AhR) Expression Disrupts Cell Proliferation and Alters Energy Metabolism and Fatty Acid Synthesis in Colon Cancer Cells. Cancers (Basel) 2022; 14:cancers14174245. [PMID: 36077780 PMCID: PMC9454859 DOI: 10.3390/cancers14174245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/12/2022] [Accepted: 08/25/2022] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Cancer cells undergo metabolic modifications in order to meet their high energetic demand. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcriptional factor primarily known as a xenobiotic sensor. However, this receptor seems to have a wide range of physiological roles in many processes including cell proliferation, migration or control of immune responses. AhR is often overexpressed in tumor cells of various tissue origin, and several studies have indicated that AhR may also contribute to regulation of cellular metabolism, including synthesis of fatty acids (FA), one of the major steps in metabolic transition. Potential links between the AhR and the control of tumor cell proliferation and metabolism thus deserve more attention. Abstract The aryl hydrocarbon receptor (AhR) plays a wide range of physiological roles in cellular processes such as proliferation, migration or control of immune responses. Several studies have also indicated that AhR might contribute to the regulation of energy balance or cellular metabolism. We observed that the AhR is upregulated in tumor epithelial cells derived from colon cancer patients. Using wild-type and the corresponding AhR knockout (AhR KO) variants of human colon cancer cell lines HCT116 and HT-29, we analyzed possible role(s) of the AhR in cell proliferation and metabolism, with a focus on regulation of the synthesis of fatty acids (FAs). We observed a decreased proliferation rate in the AhR KO cells, which was accompanied with altered cell cycle progression, as well as a decreased ATP production. We also found reduced mRNA levels of key enzymes of the FA biosynthetic pathway in AhR KO colon cancer cells, in particular of stearoyl-CoA desaturase 1 (SCD1). The loss of AhR was also associated with reduced expression and/or activity of components of the PI3K/Akt pathway, which controls lipid metabolism, and other lipogenic transcriptional regulators, such as sterol regulatory element binding transcription factor 1 (SREBP1). Together, our data indicate that disruption of AhR activity in colon tumor cells may, likely in a cell-specific manner, limit their proliferation, which could be linked with a suppressive effect on their endogenous FA metabolism. More attention should be paid to potential mechanistic links between overexpressed AhR and colon tumor cell metabolism.
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Li H, Gao YH, Song L, Chen TF, Zhang GP, Ye ZG, Gao Y, Huo W. Ginsenoside Rg1 protects mice against 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced liver injury by inhibiting CYP1A1 through the aryl hydrocarbon receptor. JOURNAL OF ETHNOPHARMACOLOGY 2022; 294:115394. [PMID: 35595219 DOI: 10.1016/j.jep.2022.115394] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/26/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Panax ginseng C. A. Meyer (ginseng) is a widely used traditional Chinese medicine that has played a beneficial role in the treatment of various diseases, including liver diseases. Ginsenoside Rg1 is a saponin isolated and purified from ginseng that exerts protective effects on the liver in some liver injury models. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitous dioxin found mostly in food products that causes liver injury and other human diseases. Although significant efforts have been made to reduce the burden of liver disease, there is still a lack of effective treatment methods. AIM OF THE STUDY Although ginsenoside Rg1 was reported to inhibit TCDD-mediated cytochrome P450 1A1 (CYP1A1) induction in HepG2 cells, we sought to verify its hepatoprotective effects and elucidate its mechanism in a TCDD-induced liver injury model in mice. MATERIAL AND METHODS The mouse liver injury model was established by intraperitoneal TCDD injection, followed by treatment with various doses of ginsenoside Rg1 (50, 100, and 200 mg/kg). Clinical indicators of liver injury, such as an increase in serum aspartate aminotransferase and alanine aminotransferase levels, as well as histopathological changes were evaluated. RESULTS The common clinical indicators of liver injury were detected following TCDD injection, including an increase in serum alanine aminotransferase and aspartate aminotransferase levels, increased relative liver weight, and histopathological changes. Following treatment with ginsenoside Rg1, the levels of aspartate aminotransferase and alanine aminotransferase decreased significantly, and the liver histology was improved. In addition, ginsenoside Rg1 competitively inhibited TCDD-induced Cyp1a1 mRNA transcription through the modulation of aryl hydrocarbon receptor (AhR) nuclear translocation. CONCLUSION Ginsenoside Rg1 is a potent partial AhR agonist that has potential as an effective medication for protecting against TCDD-associated liver injury.
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Affiliation(s)
- Han Li
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
| | - Yun-Hang Gao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
| | - Ling Song
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
| | - Teng-Fei Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
| | - Guang-Ping Zhang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
| | - Zu-Guang Ye
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
| | - Yue Gao
- Institute of Radiation Medicine Academy of Military Medical Sciences, Beijing, 100850, China.
| | - Wang Huo
- Department of Traditional Chinese Medicine, The Sixth Medical Center of PLA General Hospital, Beijing, 100048, China.
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Orlowska K, Fling RR, Nault R, Sink WJ, Schilmiller AL, Zacharewski T. Dioxin-elicited decrease in cobalamin redirects propionyl-CoA metabolism to the β-oxidation-like pathway resulting in acrylyl-CoA conjugate buildup. J Biol Chem 2022; 298:102301. [PMID: 35931118 PMCID: PMC9418907 DOI: 10.1016/j.jbc.2022.102301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022] Open
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant that induces diverse biological and toxic effects, including reprogramming intermediate metabolism, mediated by the aryl hydrocarbon receptor. However, the specific reprogramming effects of TCDD are unclear. Here, we performed targeted LC-MS analysis of hepatic extracts from mice gavaged with TCDD. We detected an increase in S-(2-carboxyethyl)-L-cysteine, a conjugate from the spontaneous reaction between the cysteine sulfhydryl group and highly reactive acrylyl-CoA, an intermediate in the cobalamin (Cbl)-independent β-oxidation-like metabolism of propionyl-CoA. TCDD repressed genes in both the canonical Cbl-dependent carboxylase and the alternate Cbl-independent β-oxidation-like pathways as well as inhibited methylmalonyl-CoA mutase (MUT) at lower doses. Moreover, TCDD decreased serum Cbl levels and hepatic cobalt levels while eliciting negligible effects on gene expression associated with Cbl absorption, transport, trafficking, or derivatization to 5'-deoxy-adenosylcobalamin (AdoCbl), the required MUT cofactor. Additionally, TCDD induced the gene encoding aconitate decarboxylase 1 (Acod1), the enzyme responsible for decarboxylation of cis-aconitate to itaconate, and dose-dependently increased itaconate levels in hepatic extracts. Our results indicate MUT inhibition is consistent with itaconate activation to itaconyl-CoA, a MUT suicide inactivator that forms an adduct with adenosylcobalamin. This adduct in turn inhibits MUT activity and reduces Cbl levels. Collectively, these results suggest the decrease in MUT activity is due to Cbl depletion following TCDD treatment, which redirects propionyl-CoA metabolism to the alternate Cbl-independent β-oxidation-like pathway. The resulting hepatic accumulation of acrylyl-CoA likely contributes to TCDD-elicited hepatotoxicity and the multihit progression of steatosis to steatohepatitis with fibrosis.
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Affiliation(s)
- Karina Orlowska
- Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA,Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Russ R. Fling
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA,Microbiology & Molecular Genetics, Michigan Sptate University, East Lansing, Michigan, USA
| | - Rance Nault
- Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA,Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Warren J. Sink
- Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA,Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Anthony L. Schilmiller
- Mass Spectrometry and Metabolomics Core, Michigan State University, East Lansing, Michigan, USA
| | - Tim Zacharewski
- Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA; Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA.
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15
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Environmental Toxicants and NAFLD: A Neglected yet Significant Relationship. Dig Dis Sci 2022; 67:3497-3507. [PMID: 34383198 DOI: 10.1007/s10620-021-07203-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 07/27/2021] [Indexed: 01/09/2023]
Abstract
The liver is an organ of vital importance in the body; it is the center of metabolic activities and acts as the primary line of defense against toxic compounds. Exposure to environmental toxicants is an unavoidable fallout from rapid industrialization across the world and is even higher in developing countries. Technological development and industrialization have led to the release of toxicants such as pollutant toxic gases, chemical discharge, industrial effluents, pesticides and solvents, into the environment. In the last few years, a growing body of evidence has shed light on the potential impact of environmental toxicants on liver health, in particular, on non-alcoholic fatty liver disease (NAFLD) incidence and progression. NAFLD is a multifactorial disease linked to metabolic derangement including diabetes and other complications. Environmental toxicants including xenobiotics and pollutants may have a direct or indirect steatogenic/fibrogenic impact on the liver and should be considered as risk factors associated with NAFLD. This review discusses the contribution of environmental toxicants toward the increasing disease burden of NAFLD.
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16
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Park JG, Iwata H, Tue NM, Kunisue T, Kim EY. Effects of 1,3,7-tribromodibenzo-p-dioxin, a natural dioxin on chicken embryos: Comparison with effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 237:113538. [PMID: 35483143 DOI: 10.1016/j.ecoenv.2022.113538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 04/15/2022] [Accepted: 04/16/2022] [Indexed: 06/14/2023]
Abstract
Several naturally occurring dioxins, including 1,3,7-tribromodibenzo-p-dioxin (1,3,7-TriBDD), synthesized by red algae, have been detected in the marine environment. As 1,3,7-TriBDD is accumulated in mussels and fish, predators, such as marine birds, are exposed to this congener, similar to anthropogenic dioxins (including 2,3,7,8-tetrachlorodibenzo-p-dioxin TCDD). However, little is known about the impact of 1,3,7-TriBDD exposure on the bird health. To understand the effects of 1,3,7-TriBDD on birds, the phenotypic effects and hepatic transcriptome were investigated in chicken (Gallus gallus) embryos treated with 27 μM (2.9 ng/g egg) and 137 μM (14.4 ng/g egg) 1,3,7-TriBDD. The blood glucose levels in the 1,3,7-TriBDD-treated groups were lower than those in the control group. The transcriptome analysis of 6520 sequences in the 27 and 137 μM 1,3,7-TriBDD-treated groups identified 733 and 596 differentially expressed genes (DEGs). Cytochrome P450 1A4 and 1A5 were also identified as DEGs, suggesting that the aryl hydrocarbon receptor is activated by this congener. Pathway and network analyses with DEGs suggested that 1,3,7-TriBDD may induce carcinogenic effects and metabolic alterations. These results were similar to the effects on TCDD-treated embryos. Nevertheless, the overall transcriptome results suggested that compared with TCDD, 1,3,7-TriBDD has a unique impact on insulin- and peroxisome-signaling pathways in chicken embryos. Differences in altered transcriptome profiles between 1,3,7-TriBDD- and TCDD-treated embryos may lead to different phenotypic effects: less severe effects of 1,3,7-TriBDD and more fatal effects of TCDD. Collectively, these findings warrant the further assessment of the hazard and risk of 1,3,7-TriBDD on marine animals, considering increased exposure due to climate change.
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Affiliation(s)
- Jae Gon Park
- Department of Biology, Kyung Hee University, Hoegi-Dong, Dongdaemun-Gu, Seoul 130-701, Republic of Korea
| | - Hisato Iwata
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan
| | - Nguyen Minh Tue
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan
| | - Tatsuya Kunisue
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan
| | - Eun-Young Kim
- Department of Biology, Kyung Hee University, Hoegi-Dong, Dongdaemun-Gu, Seoul 130-701, Republic of Korea; Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan.
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17
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Cholico GN, Nault R, Zacharewski TR. Genome-Wide ChIPseq Analysis of AhR, COUP-TF, and HNF4 Enrichment in TCDD-Treated Mouse Liver. Int J Mol Sci 2022; 23:1558. [PMID: 35163483 PMCID: PMC8836158 DOI: 10.3390/ijms23031558] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/19/2022] [Accepted: 01/27/2022] [Indexed: 02/01/2023] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor known for mediating the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. Although the canonical mechanism of AhR activation involves heterodimerization with the aryl hydrocarbon receptor nuclear translocator, other transcriptional regulators that interact with AhR have been identified. Enrichment analysis of motifs in AhR-bound genomic regions implicated co-operation with COUP transcription factor (COUP-TF) and hepatocyte nuclear factor 4 (HNF4). The present study investigated AhR, HNF4α and COUP-TFII genomic binding and effects on gene expression associated with liver-specific function and cell differentiation in response to TCDD. Hepatic ChIPseq data from male C57BL/6 mice at 2 h after oral gavage with 30 µg/kg TCDD were integrated with bulk RNA-sequencing (RNAseq) time-course (2-72 h) and dose-response (0.01-30 µg/kg) datasets to assess putative AhR, HNF4α and COUP-TFII interactions associated with differential gene expression. Functional enrichment analysis of differentially expressed genes (DEGs) identified differential binding enrichment for AhR, COUP-TFII, and HNF4α to regions within liver-specific genes, suggesting intersections associated with the loss of liver-specific functions and hepatocyte differentiation. Analysis found that the repression of liver-specific, HNF4α target and hepatocyte differentiation genes, involved increased AhR and HNF4α binding with decreased COUP-TFII binding. Collectively, these results suggested TCDD-elicited loss of liver-specific functions and markers of hepatocyte differentiation involved interactions between AhR, COUP-TFII and HNF4α.
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Affiliation(s)
| | | | - Tim R. Zacharewski
- Biochemistry & Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA; (G.N.C.); (R.N.)
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18
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Merrill AK, Anderson T, Conrad K, Marvin E, James-Todd T, Cory-Slechta DA, Sobolewski M. Protracted Impairment of Maternal Metabolic Health in Mouse Dams Following Pregnancy Exposure to a Mixture of Low Dose Endocrine-Disrupting Chemicals, a Pilot Study. TOXICS 2021; 9:346. [PMID: 34941779 PMCID: PMC8706199 DOI: 10.3390/toxics9120346] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/19/2021] [Accepted: 12/07/2021] [Indexed: 12/22/2022]
Abstract
Pregnancy, a period of increased metabolic demands coordinated by fluctuating steroid hormones, is an understudied critical window of disease susceptibility for later-life maternal metabolic health. Epidemiological studies have identified associations between exposures to various endocrine-disrupting chemicals (EDCs) with an increased risk for metabolic syndrome, obesity, and diabetes. Whether such adverse outcomes would be heightened by concurrent exposures to multiple EDCs during pregnancy, consistent with the reality that human exposures are to EDC mixtures, was examined in the current pilot study. Mouse dams were orally exposed to relatively low doses of four EDCs: (atrazine (10 mg/kg), bisphenol-A (50 µg/kg), perfluorooctanoic acid (0.1 mg/kg), 2,3,7,8-tetrachlorodibenzo-p-dioxin (0.036 µg/kg)), or the combination (MIX), from gestational day 7 until birth or for an equivalent 12 days in non-pregnant females. Glucose intolerance, serum lipids, weight, and visceral adiposity were assessed six months later. MIX-exposed dams exhibited hyperglycemia with a persistent elevation in blood glucose two hours after glucose administration in a glucose tolerance test, whereas no such effects were observed in MIX-exposed non-pregnant females. Correspondingly, MIX dams showed elevated serum low-density lipoprotein (LDL). There were no statistically significant differences in weight or visceral adipose; MIX dams showed an average visceral adipose volume to body volume ratio of 0.09, while the vehicle dams had an average ratio of 0.07. Collectively, these findings provide biological plausibility for the epidemiological associations observed between EDC exposures during pregnancy and subsequent maternal metabolic dyshomeostasis, and proof of concept data that highlight the importance of considering complex EDC mixtures based of off common health outcomes, e.g., for increased risk for later-life maternal metabolic effects following pregnancy.
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Affiliation(s)
- Alyssa K. Merrill
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA; (A.K.M.); (T.A.); (K.C.); (E.M.); (D.A.C.-S.)
| | - Timothy Anderson
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA; (A.K.M.); (T.A.); (K.C.); (E.M.); (D.A.C.-S.)
| | - Katherine Conrad
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA; (A.K.M.); (T.A.); (K.C.); (E.M.); (D.A.C.-S.)
| | - Elena Marvin
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA; (A.K.M.); (T.A.); (K.C.); (E.M.); (D.A.C.-S.)
| | - Tamarra James-Todd
- Department of Environmental Health, Harvard University, Boston, MA 02115, USA;
| | - Deborah A. Cory-Slechta
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA; (A.K.M.); (T.A.); (K.C.); (E.M.); (D.A.C.-S.)
| | - Marissa Sobolewski
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA; (A.K.M.); (T.A.); (K.C.); (E.M.); (D.A.C.-S.)
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19
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Fling RR, Zacharewski TR. Aryl Hydrocarbon Receptor (AhR) Activation by 2,3,7,8-Tetrachlorodibenzo- p-Dioxin (TCDD) Dose-Dependently Shifts the Gut Microbiome Consistent with the Progression of Non-Alcoholic Fatty Liver Disease. Int J Mol Sci 2021; 22:12431. [PMID: 34830313 PMCID: PMC8625315 DOI: 10.3390/ijms222212431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 11/17/2022] Open
Abstract
Gut dysbiosis with disrupted enterohepatic bile acid metabolism is commonly associated with non-alcoholic fatty liver disease (NAFLD) and recapitulated in a NAFLD-phenotype elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in mice. TCDD induces hepatic fat accumulation and increases levels of secondary bile acids, including taurolithocholic acid and deoxycholic acid (microbial modified bile acids involved in host bile acid regulation signaling pathways). To investigate the effects of TCDD on the gut microbiota, the cecum contents of male C57BL/6 mice orally gavaged with sesame oil vehicle or 0.3, 3, or 30 µg/kg TCDD were examined using shotgun metagenomic sequencing. Taxonomic analysis identified dose-dependent increases in Lactobacillus species (i.e., Lactobacillus reuteri). Increased species were also associated with dose-dependent increases in bile salt hydrolase sequences, responsible for deconjugation reactions in secondary bile acid metabolism. Increased L. reuteri levels were further associated with mevalonate-dependent isopentenyl diphosphate (IPP) biosynthesis and o-succinylbenzoate synthase, a menaquinone biosynthesis associated gene. Analysis of the gut microbiomes from cirrhosis patients identified an increased abundance of genes from the mevalonate-dependent IPP biosynthesis as well as several other menaquinone biosynthesis genes, including o-succinylbenzoate synthase. These results extend the association of lactobacilli with the AhR/intestinal axis in NAFLD progression and highlight the similarities between TCDD-elicited phenotypes in mice to human NAFLD.
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Affiliation(s)
- Russell R. Fling
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA;
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Timothy R. Zacharewski
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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20
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Cholico GN, Fling RR, Zacharewski NA, Fader KA, Nault R, Zacharewski TR. Thioesterase induction by 2,3,7,8-tetrachlorodibenzo-p-dioxin results in a futile cycle that inhibits hepatic β-oxidation. Sci Rep 2021; 11:15689. [PMID: 34344994 PMCID: PMC8333094 DOI: 10.1038/s41598-021-95214-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 07/15/2021] [Indexed: 02/07/2023] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a persistent environmental contaminant, induces steatosis by increasing hepatic uptake of dietary and mobilized peripheral fats, inhibiting lipoprotein export, and repressing β-oxidation. In this study, the mechanism of β-oxidation inhibition was investigated by testing the hypothesis that TCDD dose-dependently repressed straight-chain fatty acid oxidation gene expression in mice following oral gavage every 4 days for 28 days. Untargeted metabolomic analysis revealed a dose-dependent decrease in hepatic acyl-CoA levels, while octenoyl-CoA and dicarboxylic acid levels increased. TCDD also dose-dependently repressed the hepatic gene expression associated with triacylglycerol and cholesterol ester hydrolysis, fatty acid binding proteins, fatty acid activation, and 3-ketoacyl-CoA thiolysis while inducing acyl-CoA hydrolysis. Moreover, octenoyl-CoA blocked the hydration of crotonyl-CoA suggesting short chain enoyl-CoA hydratase (ECHS1) activity was inhibited. Collectively, the integration of metabolomics and RNA-seq data suggested TCDD induced a futile cycle of fatty acid activation and acyl-CoA hydrolysis resulting in incomplete β-oxidation, and the accumulation octenoyl-CoA levels that inhibited the activity of short chain enoyl-CoA hydratase (ECHS1).
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Affiliation(s)
- Giovan N Cholico
- Department of Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Russell R Fling
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Nicholas A Zacharewski
- Department of Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
| | - Kelly A Fader
- Department of Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Rance Nault
- Department of Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Timothy R Zacharewski
- Department of Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA.
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA.
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21
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Lu J, Liu M, Fan Y, Zheng H, Guan S. TCDD induced lipid accumulation by impairment of autophagic flux in THP-1 macrophages. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:36053-36059. [PMID: 33682057 DOI: 10.1007/s11356-021-13258-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a well-known environmental and food contaminant generated as a byproduct of various industrial activities. It is found in a lot of foods, especially in dairy products, eggs, fish, and meat. Autophagy is a highly conserved cellular degradation and cycling process, which plays an important role in lipid metabolism. This study aimed to explore the effects of TCDD on autophagic flux and lipid metabolism in THP-1 macrophages. The data showed that TCDD promoted the accumulation of autophagosomes in THP-1 macrophages, and subsequent findings revealed that this autophagosome accumulation was caused by the inhibition of autophagic flux by testing the expression of LC3II, p62 levels, and mRFP-GFP-LC3. Further, we found that TCDD treatment significantly increased the amount of triglyceride (TG) and total cholesterol (TC) in THP-1 macrophages. Meanwhile, pretreatment with autophagy activator (rapamycin, Rapa) efficiently relieved TCDD-induced lipid accumulation. On the contrary, pretreatment with autophagy inhibitor (Chloroquine, CQ) promoted TCDD-induced lipid accumulation. In the experiment of co-localization of LC3 and lipid droplets, the co-localization of LC3 and lipid droplets increased after TCDD induction. These results indicated that TCDD promoted lipid accumulation in THP-1 macrophages by inhibiting autophagic flux. Our findings revealed new insights into the toxicity mechanisms of TCDD.
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Affiliation(s)
- Jing Lu
- College of Food Science and Engineering, Jilin University, Changchun, Jilin, 130062, People's Republic of China
| | - Meitong Liu
- College of Food Science and Engineering, Jilin University, Changchun, Jilin, 130062, People's Republic of China
| | - Yong Fan
- College of Food Science and Engineering, Jilin University, Changchun, Jilin, 130062, People's Republic of China
| | - Haochen Zheng
- College of Food Science and Engineering, Jilin University, Changchun, Jilin, 130062, People's Republic of China
| | - Shuang Guan
- College of Food Science and Engineering, Jilin University, Changchun, Jilin, 130062, People's Republic of China.
- Key Laboratory of Zoonosis, Ministry of Education College of Veterinary Medicine, Jilin University, Changchun, Jilin, 130062, People's Republic of China.
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22
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Diani-Moore S, Marques Pedro T, Rifkind AB. Organ-specific effects on glycolysis by the dioxin-activated aryl hydrocarbon receptor. PLoS One 2020; 15:e0243842. [PMID: 33320884 PMCID: PMC7737989 DOI: 10.1371/journal.pone.0243842] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/28/2020] [Indexed: 11/30/2022] Open
Abstract
Activation of the aryl hydrocarbon receptor (AHR) by the environmental toxin dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) causes diverse toxicities, including thymus atrophy and hepatosteatosis. The mechanisms by which AHR activation by TCDD leads to these toxicities are not fully understood. Here we studied the effects of TCDD on a major energy pathway, glycolysis, using the chick embryo close to hatching, a well-established model for studying dioxin toxicity. We showed that 24 hr of TCDD treatment causes changes in glycolysis in both thymus and liver. In thymus glands, TCDD decreased mRNAs for glycolytic genes and glucose transporters, glycolytic indices and levels of IL7 mRNA, phosphorylated AKT (pAKT) and HIF1A, stimulators of glycolysis and promoters of survival and proliferation of thymic lymphocytes. In contrast, in liver, TCDD increased mRNA levels for glycolytic genes and glucose transporters, glycolytic endpoints and pAKT levels. Similarly, increases by TCDD in mRNA levels for glycolytic genes and glucose transporters in human primary hepatocytes showed that effects in chick embryo liver pertain also to human cells. Treatment with the glycolytic inhibitor 2-deoxy-d-glucose exacerbated the effects on thymus atrophy by TCDD, supporting a role for decreased glycolysis in thymus atrophy by TCDD, but did not prevent hepatosteatosis. NAD+ precursors abolished TCDD effects on glycolytic endpoints in both thymus and liver. In summary, we report here that dioxin disrupts glycolysis mediated energy metabolism in both thymus and liver, and that it does so in opposite ways, decreasing it in the thymus and increasing it in the liver. Further, the findings support NAD+ boosting as a strategy against metabolic effects of environmental pollutants such as dioxins.
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Affiliation(s)
- Silvia Diani-Moore
- Department of Pharmacology and Pharmacology PhD Program, Weill Cornell Medicine, New York, New York, United States of America
| | - Tiago Marques Pedro
- Department of Pharmacology and Pharmacology PhD Program, Weill Cornell Medicine, New York, New York, United States of America
| | - Arleen B. Rifkind
- Department of Pharmacology and Pharmacology PhD Program, Weill Cornell Medicine, New York, New York, United States of America
- * E-mail:
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23
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Mahfouz S, Mansour G, Murphy DJ, Hanano A. Dioxin impacts on lipid metabolism of soil microbes: towards effective detection and bioassessment strategies. BIORESOUR BIOPROCESS 2020. [DOI: 10.1186/s40643-020-00347-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AbstractDioxins are the most toxic known environmental pollutants and are mainly formed by human activities. Due to their structural stability, dioxins persist for extended periods and can be transported over long distances from their emission sources. Thus, dioxins can be accumulated to considerable levels in both human and animal food chains. Along with sediments, soils are considered the most important reservoirs of dioxins. Soil microorganisms are therefore highly exposed to dioxins, leading to a range of biological responses that can impact the diversity, genetics and functional of such microbial communities. Dioxins are very hydrophobic with a high affinity to lipidic macromolecules in exposed organisms, including microbes. This review summarizes the genetic, molecular and biochemical impacts of dioxins on the lipid metabolism of soil microbial communities and especially examines modifications in the composition and architecture of cell membranes. This will provide a useful scientific benchmark for future attempts at soil ecological risk assessment, as well as in identifying potential dioxin-specific-responsive lipid biomarkers. Finally, potential uses of lipid-sequestering microorganisms as a part of biotechnological approaches to the bio-management of environmental contamination with dioxins are discussed.
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24
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Leśków A, Tarnowska M, Rosińczuk J, Dobrzyński M, Kaliszewski K, Majda J, Żybura-Wszol̷a K, Sobolewska S, Diakowska D. Xanthohumol Effect on 2,3,7,8-Tetrachlorodibenzo- p-dioxin-Treated Japanese Quails in Terms of Serum Lipids, Liver Enzymes, Estradiol, and Thyroid Hormones. ACS OMEGA 2020; 5:24445-24452. [PMID: 33015460 PMCID: PMC7528308 DOI: 10.1021/acsomega.0c02896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/04/2020] [Indexed: 06/11/2023]
Abstract
Dioxins are compounds classified as persistent organic pollutants, from which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic to living organisms. TCDD is considered a carcinogen and has proinflammatory influence on animals and humans, promoting free radicals' formation, and binding with the aryl hydrocarbon receptor (AhR) leads to expression of cytochrome p-450 genes that in turn predisposes to mutations. Natural flavonoids, in this case xanthohumol (XN), have been reported to attenuate TCDD toxicity through inhibition of the transformation of the AhR. Moreover, XN shows antioxidant properties. The aim of the study was to compare the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and XN on lipid, liver enzyme, estradiol, and thyroid enzyme levels in the serum of Japanese quails. Adult, six-month-old, Japanese quails were divided into eight groups according to treatment procedures. Serum levels of total cholesterol (TCh), high-density lipoproteins (HDLs), triglycerides (TGs), estradiol, triiodothyronine, and thyroxine, and activities of alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase were measured. In comparison with the control group, 2,3,7,8-tetrachlorodibenzo-p-dioxin significantly decreased concentrations of serum HDLs and thyroid hormones and significantly increased the serum TCh level. Levels of serum TGs, liver enzymes, and estradiol were not changed after 2,3,7,8-tetrachlorodibenzo-p-dioxin treatment. Based on our data, XN treatment may also increase the levels of thyroid hormones. Moreover, the tested dioxin disrupts the liver function, especially changing lipids' metabolism. Therefore, more studies are needed for better understanding the mechanism of toxic influence of 2,3,7,8-tetrachlorodibenzo-p-dioxin on key metabolic pathways and organs in living organisms.
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Affiliation(s)
- Anna Leśków
- Department of Nervous System Diseases, Wroclaw Medical University, Wroclaw 51618, Poland
| | - Mal̷gorzata Tarnowska
- Department of Nervous System Diseases, Wroclaw Medical University, Wroclaw 51618, Poland
| | - Joanna Rosińczuk
- Department of Nervous System Diseases, Wroclaw Medical University, Wroclaw 51618, Poland
| | - Maciej Dobrzyński
- Department of Conservative Dentistry and Pedodontics, Wroclaw Medical University, Wroclaw 50425, Poland
| | - Krzysztof Kaliszewski
- Department of General, Gastroenterological and Endocrinological
Surgery, Wroclaw Medical University, Wroclaw 50369, Poland
| | - Jacek Majda
- Department of Laboratory Diagnostics,
4th Military Hospital, Wroclaw 50981, Poland
| | | | - Sylwia Sobolewska
- Department
of Animal Nutrition and Feed Management, Wroclaw University of Environmental and Life Sciences, Wroclaw, 51630, Poland
| | - Dorota Diakowska
- Department of Nervous System Diseases, Wroclaw Medical University, Wroclaw 51618, Poland
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25
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Fling RR, Doskey CM, Fader KA, Nault R, Zacharewski TR. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) dysregulates hepatic one carbon metabolism during the progression of steatosis to steatohepatitis with fibrosis in mice. Sci Rep 2020; 10:14831. [PMID: 32908189 PMCID: PMC7481292 DOI: 10.1038/s41598-020-71795-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/29/2020] [Indexed: 12/13/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a persistent environmental contaminant, induces steatosis that can progress to steatohepatitis with fibrosis, pathologies that parallel stages in the development of non-alcoholic fatty liver disease (NAFLD). Coincidently, one carbon metabolism (OCM) gene expression and metabolites are often altered during NAFLD progression. In this study, the time- and dose-dependent effects of TCDD were examined on hepatic OCM in mice. Despite AhR ChIP-seq enrichment at 2 h, OCM gene expression was not changed within 72 h following a bolus dose of TCDD. Dose-dependent repression of methionine adenosyltransferase 1A (Mat1a), adenosylhomocysteinase (Achy) and betaine-homocysteine S-methyltransferase (Bhmt) mRNA and protein levels following repeated treatments were greater at 28 days compared to 8 days. Accordingly, levels of methionine, betaine, and homocysteic acid were dose-dependently increased, while S-adenosylmethionine, S-adenosylhomocysteine, and cystathionine exhibited non-monotonic dose-dependent responses consistent with regulation by OCM intermediates and repression of glycine N-methyltransferase (Gnmt). However, the dose-dependent effects on SAM-dependent metabolism of polyamines and creatine could not be directly attributed to alterations in SAM levels. Collectively, these results demonstrate persistent AhR activation disrupts hepatic OCM metabolism at the transcript, protein and metabolite levels within context of TCDD-elicited progression of steatosis to steatohepatitis with fibrosis.
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Affiliation(s)
- Russell R Fling
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Claire M Doskey
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Kelly A Fader
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Rance Nault
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Tim R Zacharewski
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA.
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26
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Li C, Liu Y, Dong Z, Xu M, Gao M, Cong M, Liu S. TCDD promotes liver fibrosis through disordering systemic and hepatic iron homeostasis. JOURNAL OF HAZARDOUS MATERIALS 2020; 395:122588. [PMID: 32325343 DOI: 10.1016/j.jhazmat.2020.122588] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/19/2020] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin (TCDD) is a toxic environmental pollutant which can cause severe health problems, such as fibrosis. However, the toxic effects and related mechanism of TCDD on the liver remain largely unknown. In this study, we established a liver fibrosis mouse model upon exposure of TCDD, as evidenced by increased collagen I, tumor growth factor β1 (TGFβ1), α-smooth muscle actin (α-SMA), and Masson staining. Meanwhile, there was also a significant increase of inflammatory factors and TUNEL-positive hepatocytes in liver, indicating that liver inflammation and hepatic cell apoptosis occurred. In addition, increased serum and liver iron were concomitant with liver injury induced by TCDD. We further investigated the mechanism underlying TCDD-induced hepatocyte apoptosis through apoptosis polymerase chain reaction array, and found that a crucial apoptosis-related gene, cell death-inducing DFF45-like effector b (Cideb), was significantly increased in primary hepatocytes from TCDD-exposed mice, and accompanied by liver iron deposition in hepcidin knockout mice. Therefore, Cideb depletion could effectively attenuated TCDD or iron induced cell death related genes expression. In conclusion, our results showed that iron-induced Cideb expression played a critical role in promoting TCDD-induced hepatocyte apoptosis and liver fibrosis, which provide a novel mechanism for understanding TCDD-induced liver injury.
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Affiliation(s)
- Changying Li
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis and National Clinical Research Center of Digestive Diseases, Beijing, 100050, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Yingying Liu
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis and National Clinical Research Center of Digestive Diseases, Beijing, 100050, China
| | - Zheng Dong
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Gao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Min Cong
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis and National Clinical Research Center of Digestive Diseases, Beijing, 100050, China.
| | - Sijin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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27
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Doskey CM, Fader KA, Nault R, Lydic T, Matthews J, Potter D, Sharratt B, Williams K, Zacharewski T. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) alters hepatic polyunsaturated fatty acid metabolism and eicosanoid biosynthesis in female Sprague-Dawley rats. Toxicol Appl Pharmacol 2020; 398:115034. [PMID: 32387183 PMCID: PMC7294678 DOI: 10.1016/j.taap.2020.115034] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/16/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent aryl hydrocarbon receptor (AhR) agonist that elicits a broad spectrum of dose-dependent hepatic effects including lipid accumulation, inflammation, and fibrosis. To determine the role of inflammatory lipid mediators in TCDD-mediated hepatotoxicity, eicosanoid metabolism was investigated. Female Sprague-Dawley (SD) rats were orally gavaged with sesame oil vehicle or 0.01-10 μg/kg TCDD every 4 days for 28 days. Hepatic RNA-Seq data was integrated with untargeted metabolomics of liver, serum, and urine, revealing dose-dependent changes in linoleic acid (LA) and arachidonic acid (AA) metabolism. TCDD also elicited dose-dependent differential gene expression associated with the cyclooxygenase, lipoxygenase, and cytochrome P450 epoxidation/hydroxylation pathways with corresponding changes in ω-6 (e.g. AA and LA) and ω-3 polyunsaturated fatty acids (PUFAs), as well as associated eicosanoid metabolites. Overall, TCDD increased the ratio of ω-6 to ω-3 PUFAs. Phospholipase A2 (Pla2g12a) was induced consistent with increased AA metabolism, while AA utilization by induced lipoxygenases Alox5 and Alox15 increased leukotrienes (LTs). More specifically, TCDD increased pro-inflammatory eicosanoids including leukotriene LTB4, and LTB3, known to recruit neutrophils to damaged tissue. Dose-response modeling suggests the cytochrome P450 hydroxylase/epoxygenase and lipoxygenase pathways are more sensitive to TCDD than the cyclooxygenase pathway. Hepatic AhR ChIP-Seq analysis found little enrichment within the regulatory regions of differentially expressed genes (DEGs) involved in eicosanoid biosynthesis, suggesting TCDD-elicited dysregulation of eicosanoid metabolism is a downstream effect of AhR activation. Overall, these results suggest alterations in eicosanoid metabolism may play a key role in TCDD-elicited hepatotoxicity associated with the progression of steatosis to steatohepatitis.
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Affiliation(s)
- Claire M Doskey
- Department of Biochemistry & Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, United States
| | - Kelly A Fader
- Department of Biochemistry & Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, United States
| | - Rance Nault
- Department of Biochemistry & Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, United States
| | - Todd Lydic
- Department of Physiology, Michigan State University, East Lansing, MI 48824, United States
| | - Jason Matthews
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo 0316, Norway
| | - Dave Potter
- Wellington Laboratories Inc., Guelph, Ontario NIG 3M5, Canada
| | - Bonnie Sharratt
- Wellington Laboratories Inc., Guelph, Ontario NIG 3M5, Canada
| | - Kurt Williams
- Department of Pathobiology and Diagnostic Investigation, Michigan State, East Lansing, MI 48824, United States
| | - Tim Zacharewski
- Department of Biochemistry & Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, United States.
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28
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Huerta-Yepez S, Tirado-Rodriguez A, Montecillo-Aguado MR, Yang J, Hammock BD, Hankinson O. Aryl Hydrocarbon Receptor-Dependent inductions of omega-3 and omega-6 polyunsaturated fatty acid metabolism act inversely on tumor progression. Sci Rep 2020; 10:7843. [PMID: 32398692 PMCID: PMC7217871 DOI: 10.1038/s41598-020-64146-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/13/2020] [Indexed: 12/21/2022] Open
Abstract
The Western diet contains a high ratio of omega-6 (ω6) to omega-3 (ω3) polyunsaturated fatty acids (PUFA). The prototypical aryl hydrocarbon receptor (AHR) ligand, 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), induces CYP1 family enzymes, which can metabolize PUFA to epoxides. Mice fed ω3-rich or ω6-rich diets were treated with TCDD and injected subcutaneously with AHR-competent Hepa1-GFP hepatoma cells or AHR-deficient LLC lung cancer cells. TCDD reduced the growth rates of the resulting tumors in ω3-fed mice and inhibited their metastasis to the liver and/or lung, but had the opposite effects in mice fed ω6 PUFA. These responses were likely attributable to the corresponding PUFA epoxides generated in tumor cells and/or host, since many depended upon co-administration of a soluble epoxide hydrolase (EPHX2) inhibitor in males, and/or were associated with increases in epoxide levels in tumors and sites of metastasis. Equivalent effects occurred in females in the absence of EPHX2 inhibition, probably because this sex expressed reduced levels of EPHX2. The responses elicited by TCDD were associated with effects on tumor vascularity, tumor cell proliferation and/or apoptosis. Thus environmental AHR agonists, and potentially also endogenous, nutritional, and microbiome-derived agonists, may reduce or enhance cancer progression depending on the composition of dietary PUFA, particularly in females.
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Affiliation(s)
- Sara Huerta-Yepez
- Department of Pathology & Laboratory Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Ana Tirado-Rodriguez
- Department of Pathology & Laboratory Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Mayra R Montecillo-Aguado
- Research Unit of Oncology Diseases. Hospital Infantil de Mexico, Federico Gomez, Mexico City, Mexico
| | - Jun Yang
- Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA, 95616, USA
| | - Bruce D Hammock
- Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA, 95616, USA
| | - Oliver Hankinson
- Department of Pathology & Laboratory Medicine, University of California, Los Angeles, CA, 90095, USA.
- Molecular Toxicology Interdepartmental Program and Department of Environmental Health Sciences, University of California, Los Angeles, CA, 90095, USA.
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29
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Selective Ah receptor modulators attenuate NPC1L1-mediated cholesterol uptake through repression of SREBP-2 transcriptional activity. J Transl Med 2020; 100:250-264. [PMID: 31417158 PMCID: PMC6989381 DOI: 10.1038/s41374-019-0306-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/26/2019] [Accepted: 07/02/2019] [Indexed: 02/07/2023] Open
Abstract
The ability of the aryl hydrocarbon receptor (AHR) to alter hepatic expression of cholesterol synthesis genes in a DRE-independent manner in mice and humans has been reported. We have examined the influence of functionally distinct classes of AHR ligands on the levels of Niemann-Pick C1-like intracellular cholesterol transporter (NPC1L1) and enzymes involved in the cholesterol synthesis pathway. NPC1L1 is known to mediate the intestinal absorption of dietary cholesterol and is clinically targeted. AHR ligands were capable of attenuating cholesterol uptake through repression of NPC1L1 expression. Through mutagenesis experiments targeting the two DRE sequences present in the promoter region of the NPC1L1 gene, we provide evidence that the repression does not require functional DRE sequences; while knockdown experiments demonstrated that this regulation is dependent on AHR and sterol-regulatory element-binding protein-2 (SREBP-2). Furthermore, upon ligand activation of AHR, the human intestinal Caco-2 cell line revealed coordinate repression of both mRNA and protein levels for a number of the cholesterol biosynthetic enzymes. Transcription of NPC1L1 and genes of the cholesterol synthesis pathway is predominantly regulated by SREBP-2, especially after treatment with a statin. Immunoblot analyses revealed a significant decrease in transcriptionally active SREBP-2 levels upon ligand treatment, whereas the precursor form of SREBP-2 was modestly increased by AHR activation. Mechanistic insights indicate that AHR induces proteolytic degradation of mature SREBP-2 in a calcium-dependent manner, which correlates with the AHR ligand-mediated upregulation of the transient receptor potential cation channel subfamily V member 6 (TRPV6) gene encoding for a membrane calcium channel. These observations emphasize a role for AHR in the systemic homeostatic regulation of cholesterol synthesis and absorption, indicating the potential use of this receptor as a target for the treatment of hyperlipidosis-associated metabolic diseases.
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30
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Dornbos P, Jurgelewicz A, Fader KA, Williams K, Zacharewski TR, LaPres JJ. Characterizing the Role of HMG-CoA Reductase in Aryl Hydrocarbon Receptor-Mediated Liver Injury in C57BL/6 Mice. Sci Rep 2019; 9:15828. [PMID: 31676775 PMCID: PMC6825130 DOI: 10.1038/s41598-019-52001-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/11/2019] [Indexed: 12/25/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor. The prototypical ligand of the AHR is an environmental contaminant called 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). TCDD exposure is associated with many adverse health outcomes in humans including non-alcoholic fatty liver disease (NAFLD). Previous studies suggest that AHR ligands alter cholesterol homeostasis in mice through repression of genes involved in cholesterol biosynthesis, such as Hmgcr, which encodes the rate-limiting enzyme of cholesterol biosynthesis called 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCR). In this study, we sought to characterize the impact of HMGCR repression in TCDD-induced liver injury. C57BL/6 mice were exposed to TCDD in the presence or absence of simvastatin, a competitive inhibitor of HMGCR. Simvastatin exposure decreased TCDD-induced hepatic lipid accumulation in both sexes, but was most prominent in females. Simvastatin and TCDD (S + T) co-treatment increased hepatic AHR-battery gene expression and liver injury in male, but not female, mice. In addition, the S + T co-treatment led to an increase in hepatic glycogen content that coincides with heavier liver in female mice. Results from this study suggest that statins, which are amongst the most prescribed pharmaceuticals, may protect from AHR-mediated steatosis, but alter glycogen metabolism and increase the risk of TCDD-elicited liver damage in a sex-specific manner.
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Affiliation(s)
- Peter Dornbos
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.,Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Amanda Jurgelewicz
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Pharmacology and Toxicology, Michigan State, East Lansing, MI, 48824, USA
| | - Kelly A Fader
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.,Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Kurt Williams
- Department of Pathobiology and Diagnostic Investigation, Michigan State, East Lansing, MI, 48824, USA
| | - Timothy R Zacharewski
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.,Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - John J LaPres
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA. .,Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA.
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Silva JCP, Marques C, Martins FO, Viegas I, Tavares L, Macedo MP, Jones JG. Determining contributions of exogenous glucose and fructose to de novo fatty acid and glycerol synthesis in liver and adipose tissue. Metab Eng 2019; 56:69-76. [PMID: 31473320 DOI: 10.1016/j.ymben.2019.08.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/26/2019] [Accepted: 08/22/2019] [Indexed: 12/25/2022]
Abstract
The de novo synthesis of triglyceride (TG) fatty acids (FA) and glycerol can be measured with stable isotope tracers. However, these methods typically do not inform the contribution of a given substrate to specific pathways on these synthetic processes. We integrated deuterated water (2H2O) measurement of de novo lipogenesis (DNL) and glycerol-3-phosphate (GLY) synthesis from all substrates with a 13C nuclear magnetic resonance (NMR) method that quantifies TG FA and glycerol enrichment from a specific [U-13C]precursor. This allowed the [U-13C]precursor contribution to DNL and GLY to be estimated. We applied this method in mice to determine the contributions of fructose and glucose supplemented in the drinking water to DNL and GLY in liver, mesenteric adipose tissue (MAT) and subcutaneous adipose tissue (SCAT). In liver, fructose contributed significantly more to DNL of saturated fatty acids (SFA) and oleate as well as to GLY compared to glucose. Moreover, its contribution to SFA synthesis was significantly higher compared to that of oleate. MAT and SCAT had lower fractional rates of total DNL and GLY compared to liver and glucose was utilized more predominantly than fructose for TG synthesis in these tissues. This novel 2H2O/13C integrated method revealed for the first time, tissue specific selection of substrates for DNL, particularly fructose in regard to glucose in liver. Also, this approach was able to resolve the distribution of specific FAs into the TG sn2 and sn1,3 sites. This stable isotope integrated approach yielded information so far uncovered by other lipidomic tools and should powerfully assist in other nutritional, pathological or environmental contexts.
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Affiliation(s)
- João C P Silva
- Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
| | - Cátia Marques
- Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
| | - Fátima O Martins
- CEDOC-Chronic Diseases Research Center, NOVA Medical School / Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Ivan Viegas
- CFE - Center for Functional Ecology, University of Coimbra, Apartado 3046, 3001-401, Coimbra, Portugal
| | - Ludgero Tavares
- Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
| | - Maria Paula Macedo
- CEDOC-Chronic Diseases Research Center, NOVA Medical School / Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal; APDP-Portuguese Diabetes Association, Lisbon, Portugal; Department of Medical Sciences, Universidade Aveiro, Aveiro, Portugal.
| | - John G Jones
- Center for Neurosciences and Cell Biology, University of Coimbra, Portugal; APDP-Portuguese Diabetes Association, Lisbon, Portugal.
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32
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Muku GE, Blazanin N, Dong F, Smith PB, Thiboutot D, Gowda K, Amin S, Murray IA, Perdew GH. Selective Ah receptor ligands mediate enhanced SREBP1 proteolysis to restrict lipogenesis in sebocytes. Toxicol Sci 2019; 171:146-158. [PMID: 31225620 PMCID: PMC6736396 DOI: 10.1093/toxsci/kfz140] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/01/2019] [Accepted: 06/03/2019] [Indexed: 12/12/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) mediates 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) induced toxicity that can lead to chloracne in humans. A characteristic of chloracne, in contrast to acne vulgaris, is shrinkage or loss of sebaceous glands. Acne vulgaris, on the other hand, is often accompanied by excessive sebum production. Here, we examined the role of AHR in lipid synthesis in human sebocytes using distinct classes of AHR ligands. Modulation of AHR activity attenuated the expression of lipogenic genes and key pro-inflammatory markers in the absence of canonical DRE-driven transcription of the AHR target gene CYP1A1. Furthermore, topical treatment with TCDD, which mediates DRE-dependent activity, and SGA360, which fails to induce DRE-mediated responses, both exhibited a decrease in the size of sebaceous glands and the number of sebocytes within each gland in the skin. To elucidate the mechanism of AHR-mediated repression of lipid synthesis, we demonstrated that selective AHR modulators, SGA360 and SGA315 increased the protein turnover of the mature sterol regulatory element-binding protein (mSREBP-1), the principal transcriptional regulator of the fatty acid synthesis pathway. Interestingly, selective AHR ligand treatment significantly activated the AMPK-dependent kinase (AMPK) in sebocytes. Moreover, we demonstrated an inverse correlation between the active AMPK and the mSREBP-1 protein, which is consistent with the previously reported role of AMPK in inhibiting cleavage of SREBP-1. Overall, our findings indicate a DRE-independent function of selective AHR ligands in modulating lipid synthesis in human sebocytes, which might raise the possibility of using AHR as a therapeutic target for treatment of acne.
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Affiliation(s)
- Gulsum E Muku
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Nicholas Blazanin
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Fangcong Dong
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Philip B Smith
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA
| | - Diane Thiboutot
- Department of Dermatology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Krishne Gowda
- Department of Pharmacology or Penn State College of Medicine, Hershey, Pennsylvania
| | - Shantu Amin
- Department of Pharmacology or Penn State College of Medicine, Hershey, Pennsylvania
| | - Iain A Murray
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Gary H Perdew
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, Pennsylvania, USA
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33
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Yu Z, Mao C, Fu X, Ma M. High Density Lipoprotein from Egg Yolk (EYHDL) Improves Dyslipidemia by Mediating Fatty Acids Metabolism in High Fat Diet-induced Obese Mice. Food Sci Anim Resour 2019; 39:179-196. [PMID: 31149661 PMCID: PMC6533406 DOI: 10.5851/kosfa.2018.e38] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/14/2018] [Accepted: 09/17/2018] [Indexed: 12/30/2022] Open
Abstract
We investigated the effect of high density lipoprotein from egg yolk (EYHDL) on
serum, hepatic and fecal lipid and fatty acids (FAs) levels and on gene
expression involved in FAs metabolism. Male KM mice were fed either normal diet
(ND; n=20), high fat diet (HFD; n=20), or high fat diet containing
EYHDL (EYHDL; 0.6 mg/g, every day by oral gavage, n=20) for 100 days. At
the end of the experiment, the effects of treatments on biochemical parameters,
FAs profiles and involved gene expression were analyzed. Our results revealed
that EYHDL markedly suppressed the body weight gain, accumulation of abdominal
fat tissues, serum concentrations of LDL-cholesterol (LDL-C) and triglycerides,
hepatic triglycerides and cholesterol accumulation, while increased serum
concentration of HDL-cholesterol (HDL-C). EYHDL intake also increased total
cholesterol (TC) excretions compared with HFD group. Moreover, it alleviated the
severity of fatty liver and improved glucose and insulin tolerance compared with
HFD. More importantly, EYHDL partially normalized FAs profiles in serum, liver
and fecaces and neutralized the HFD-induced upregulation of SREBP-1c, Acaca,
Fasn, GPAT and Scd1. In conclusion, our findings indicate that EYHDL may have
the potential to improve metabolic disturbances that occur in HFD mice and can
be considered as an appropriate dietary recommendation for the treatment of
metabolic syndrome (MetS).
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Affiliation(s)
- Zhihui Yu
- National R&D Center for Egg Processing, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Changyi Mao
- National R&D Center for Egg Processing, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Xing Fu
- National R&D Center for Egg Processing, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Meihu Ma
- National R&D Center for Egg Processing, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
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Wahlang B, Jin J, Hardesty JE, Head KZ, Shi H, Falkner KC, Prough RA, Klinge CM, Cave MC. Identifying sex differences arising from polychlorinated biphenyl exposures in toxicant-associated liver disease. Food Chem Toxicol 2019; 129:64-76. [PMID: 31026535 DOI: 10.1016/j.fct.2019.04.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/24/2019] [Accepted: 04/06/2019] [Indexed: 12/14/2022]
Abstract
Exposures to persistent environmental pollutants like polychlorinated biphenyls (PCBs) has been associated with liver diseases such as toxicant-associated steatohepatitis (TASH). However, previously published PCB hepatotoxicity studies evaluated mostly male animal models. Moreover, epidemiologic studies on PCB-exposed cohorts evaluating sex differences are scarce. Therefore, the objective of this study was to examine hepato-toxicological responses of PCB exposures in the context of sex-dependent outcomes. Male and female C57Bl/6 mice were exposed to Aroclor 1260 (20 mg/kg), and PCB126 (20 μg/kg), by gavage for two weeks. Female mice appeared to be more sensitive to PCB-induced hepatotoxic effects as manifested by increased liver injury markers, namely, hepatic Serpine1 expression. Additionally, compared to their male counterparts, PCB-exposed females exhibited dysregulated hepatic gene expression favoring lipid accumulation rather than lipid breakdown; accompanied by dyslipidemia. Sex differences were also observed in the expression and activation of PCB targets such as the epidermal growth factor receptor (EGFR) while PCB-induced pancreatic toxicity was similar in both sexes. Importantly, PCB exposure appeared to cause pro-androgenic, anti-estrogenic along with sex-dependent thyroid hormone effects. The overall findings demonstrated that the observed PCB-mediated hepatotoxicity was sex-dependent; confirming the existence of sex differences in environmental exposure-induced markers of TASH and warrants further investigation.
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Affiliation(s)
- Banrida Wahlang
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA; UofL Superfund Research Center, University of Louisville, Louisville, KY, USA
| | - Jian Jin
- Department of Pharmacology & Toxicology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Josiah E Hardesty
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Kimberly Z Head
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Hongxue Shi
- Department of Cell & Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - K Cameron Falkner
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Russell A Prough
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Carolyn M Klinge
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Matthew C Cave
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA; UofL Superfund Research Center, University of Louisville, Louisville, KY, USA; Department of Pharmacology & Toxicology, School of Medicine, University of Louisville, Louisville, KY, USA; Department of Biochemistry & Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY, USA; Robley Rex Veterans Affairs Medical Center, Louisville, KY, USA.
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35
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D'Adamo E, Castorani V, Nobili V. The Liver in Children With Metabolic Syndrome. Front Endocrinol (Lausanne) 2019; 10:514. [PMID: 31428049 PMCID: PMC6687849 DOI: 10.3389/fendo.2019.00514] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/15/2019] [Indexed: 12/17/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is recognized as an emerging health risk in obese children and adolescents. NAFLD represents a wide spectrum of liver conditions, ranging from asymptomatic steatosis to steatohepatitis. The growing prevalence of fatty liver disease in children is associated with an increased risk of metabolic and cardiovascular complications. NAFLD is considered the hepatic manifestation of Metabolic Syndrome (MetS) and several lines of evidence have reported that children with NAFLD present one or more features of MetS. The pathogenetic mechanisms explaining the interrelationships between fatty liver disease and MetS are not clearly understood. Altough central obesity and insulin resistance seem to represent the core of the pathophysiology in both diseases, genetic susceptibility and enviromental triggers are emerging as crucial components promoting the development of NAFLD and MetS in children. In the present review we have identified and summarizied studies discussing current pathogenetic data of the association between NAFLD and MetS in children.
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Affiliation(s)
- Ebe D'Adamo
- Department of Neonatology, University of Chieti, Chieti, Italy
- *Correspondence: Ebe D'Adamo
| | | | - Valerio Nobili
- Department of Pediatrics, University “La Sapienza”, Rome, Italy
- Hepatology, Gastroenterology and Nutrition Unit, IRCCS “Bambino Gesù” Children's Hospital, Rome, Italy
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Girolami F, Badino P, Spalenza V, Manzini L, Renzone G, Salzano AM, Dal Piaz F, Scaloni A, Rychen G, Nebbia C. Identification of candidate biomarkers of the exposure to PCBs in contaminated cattle: A gene expression- and proteomic-based approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 640-641:22-30. [PMID: 29852444 DOI: 10.1016/j.scitotenv.2018.05.284] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/23/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
Dioxins and polychlorinated biphenyls (PCBs) are widespread and persistent contaminants. Through a combined gene expression/proteomic-based approach, candidate biomarkers of the exposure to such environmental pollutants in cattle subjected to a real eco-contamination event were identified. Animals were removed from the polluted area and fed a standard ration for 6 months. The decontamination was monitored by evaluating dioxin and PCB levels in pericaudal fat two weeks after the removal from the contaminated area (day 0) and then bimonthly for six months (days 59, 125 and 188). Gene expression measurements demonstrated that CYP1B1 expression was significantly higher in blood lymphocytes collected in contaminated animals (day 0), and decreased over time during decontamination. mRNA levels of interleukin 2 showed an opposite quantitative trend. MALDI-TOF-MS polypeptide profiling of serum samples ascertained a progressive decrease (from day 0 to 188) of serum levels of fibrinogen β-chain and serpin A3-7-like fragments, apolipoprotein (APO) C-II and serum amyloid A-4 protein, along with an augmented representation of transthyretin isoforms, as well as APOC-III and APOA-II proteins during decontamination. When differentially represented species were combined with serum antioxidant, acute phase and proinflammatory protein levels already ascertained in the same animals (Cigliano et al., 2016), bioinformatics unveiled an interaction network linking together almost all components. This suggests the occurrence of a complex PCB-responsive mechanism associated with animal contamination/decontamination, including a cohort of protein/polypeptide species involved in blood redox homeostasis, inflammation and lipid transport. All together, these results suggest the use in combination of such biomarkers for identifying PCB-contaminated animals, and for monitoring the restoring of their healthy condition following a decontamination process.
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Affiliation(s)
- F Girolami
- Department of Veterinary Sciences, University of Torino, Largo P. Braccini 2, Grugliasco, Italy
| | - P Badino
- Department of Veterinary Sciences, University of Torino, Largo P. Braccini 2, Grugliasco, Italy
| | - V Spalenza
- Department of Veterinary Sciences, University of Torino, Largo P. Braccini 2, Grugliasco, Italy
| | - L Manzini
- Department of Veterinary Sciences, University of Torino, Largo P. Braccini 2, Grugliasco, Italy
| | - G Renzone
- Proteomics and Mass Spectrometry Laboratory, ISPAAM, National Research Council, Via Argine 1085, Napoli, Italy
| | - A M Salzano
- Proteomics and Mass Spectrometry Laboratory, ISPAAM, National Research Council, Via Argine 1085, Napoli, Italy
| | - F Dal Piaz
- Department of Medicine and Surgery, University of Salerno, Via Giovanni Paolo II 132, Fisciano, Italy
| | - A Scaloni
- Proteomics and Mass Spectrometry Laboratory, ISPAAM, National Research Council, Via Argine 1085, Napoli, Italy
| | - G Rychen
- Unité de Recherches Animal et Fonctionnalités des Produits Animaux, INRA-Université de Lorraine, 2 av de la forêt de Haye, Vandoeuvre-lès-Nancy Cedex, France
| | - C Nebbia
- Department of Veterinary Sciences, University of Torino, Largo P. Braccini 2, Grugliasco, Italy.
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Klaunig JE, Li X, Wang Z. Role of xenobiotics in the induction and progression of fatty liver disease. Toxicol Res (Camb) 2018; 7:664-680. [PMID: 30090613 PMCID: PMC6062016 DOI: 10.1039/c7tx00326a] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/09/2018] [Indexed: 12/12/2022] Open
Abstract
Non-alcoholic fatty liver disease is a major cause of chronic liver pathology in humans. Fatty liver disease involves the accumulation of hepatocellular fat in hepatocytes that can progress to hepatitis. Steatohepatitis is categorized into alcoholic (ASH) or non-alcoholic (NASH) steatohepatitis based on the etiology of the insult. Both pathologies involve an initial steatosis followed by a progressive inflammation of the liver and eventual hepatic fibrosis (steatohepatitis) and cirrhosis. The involvement of pharmaceuticals and other chemicals in the initiation and progression of fatty liver disease has received increased study. This review will examine not only how xenobiotics initiate hepatic steatosis and steatohepatitis but also how the presence of fatty liver may modify the metabolism and pathologic effects of xenobiotics. The feeding of a high fat diet results in changes in the expression of nuclear receptors that are involved in adaptive and adverse liver effects following xenobiotic exposure. High fat diets also modulate cellular and molecular pathways involved in inflammation, metabolism, oxidative phosphorylation and cell growth. Understanding the role of hepatic steatosis and steatohepatitis on the sequelae of toxic and pathologic changes seen following xenobiotic exposure has importance in defining proper and meaningful human risk characterization of the drugs and other chemical agents.
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Affiliation(s)
- James E Klaunig
- Indiana University , School of Public Health , Bloomington , Indiana , USA .
| | - Xilin Li
- Indiana University , School of Public Health , Bloomington , Indiana , USA .
| | - Zemin Wang
- Indiana University , School of Public Health , Bloomington , Indiana , USA .
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Deierlein AL, Rock S, Park S. Persistent Endocrine-Disrupting Chemicals and Fatty Liver Disease. Curr Environ Health Rep 2018; 4:439-449. [PMID: 28980219 DOI: 10.1007/s40572-017-0166-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW Non-alcoholic fatty liver disease (NAFLD) is the most prominent chronic liver disease in Western countries, affecting approximately 25% of the population worldwide. Sex-specific differences in the development of NAFLD are apparent. While obesity and insulin resistance are major contributors to the increasing prevalence of NAFLD, a growing body of literature suggests that exposure to persistent endocrine-disrupting chemicals (pEDCs) may also play a role. This review summarizes recent (2011 and later) scientific literature investigating exposures to pEDCs, specifically persistent organic pollutants (POPs), and NAFLD, with a focus on sex-specific associations. RECENT FINDINGS The overwhelming majority of studies were conducted in single-sex animal models and provide biological evidence that exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin polychlorinated biphenyls, and other POPs or POP mixtures are negatively associated with liver health. There were four cross-sectional epidemiological studies in humans that reported associations for several POPs, including polychlorinated biphenyls and perfluorinated chemicals, with elevated liver enzymes. Only one of these studies, using a sample of gastric bypass surgery patients, examined sex-specific associations of POPs and liver enzymes, finding adverse associations among women only. The noticeable lack of studies investigating how differences (i.e., biochemical, physiological, and behavioral) between men and women may influence associations of pEDCs and NAFLD represents a large research gap in environmental health. Sexual dimorphism in metabolic processes throughout the body, including the liver, is established but often overlooked in the designs and analyses of studies. Other factors identified in this review that may also act to modulate associations of environmental chemicals and NAFLD are reproductive status and dietary nutrient intakes, which also remain understudied in the literature. Despite knowledge of sexual dimorphism in the actions of pEDCs, as well as in metabolic processes related to NAFLD development, few experimental or epidemiological studies have investigated sex-dependent associations. Future studies, especially those in humans, should be designed to address this research need. Consideration of other factors, such as reproductive status, dietary intakes, and mixtures of chemicals with varying endocrine-disrupting capabilities, should be explored.
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Affiliation(s)
- Andrea L Deierlein
- College of Global Public Health, New York University, 715/719 Broadway 12th Floor, New York, NY, 10003, USA.
| | - Sarah Rock
- College of Global Public Health, New York University, 715/719 Broadway 12th Floor, New York, NY, 10003, USA
| | - Sally Park
- College of Global Public Health, New York University, 715/719 Broadway 12th Floor, New York, NY, 10003, USA
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Endocrine Disruptors Leading to Obesity and Related Diseases. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14101282. [PMID: 29064461 PMCID: PMC5664782 DOI: 10.3390/ijerph14101282] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 10/17/2017] [Accepted: 10/19/2017] [Indexed: 12/15/2022]
Abstract
The review aims to comprehensively present the impact of exposure to endocrine disruptors (EDs) in relation to the clinical manifestation of obesity and related diseases, including diabetes mellitus, metabolic syndrome, cardiovascular diseases, carcinogenesis and infertility. EDs are strong participants in the obesity epidemic scenery by interfering with cellular morphological and biochemical processes; by inducing inflammatory responses; and by presenting transcriptional and oncogenic activity. Obesity and lipotoxicity enhancement occur through reprogramming and/or remodeling of germline epigenome by exposure to EDs. Specific population groups are vulnerable to ED exposure due to current dietary and environmental conditions. Obesity, morbidity and carcinogenicity induced by ED exposure are an evolving reality. Therefore, a new collective strategic approach is deemed essential, for the reappraisal of current global conditions pertaining to energy management.
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40
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Kania-Korwel I, Wu X, Wang K, Lehmler HJ. Identification of lipidomic markers of chronic 3,3',4,4',5-pentachlorobiphenyl (PCB 126) exposure in the male rat liver. Toxicology 2017; 390:124-134. [PMID: 28890136 PMCID: PMC5633524 DOI: 10.1016/j.tox.2017.09.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/28/2017] [Accepted: 09/05/2017] [Indexed: 12/14/2022]
Abstract
Exposure to PCB 126, an environmentally relevant aryl hydrocarbon receptor agonist, is an environmental factor causing hepatic steatosis in rodent models; however, the lipidome of PCB 126-exposed rats has not been investigated in-depth. The objective of the present study was therefore to characterize dose-dependent changes in the lipid profile in the liver of male Sprague-Dawley rats exposed to PCB 126. Rats were exposed for three month to intraperitoneal injections of 0.01, 0.05 and 0.2μmol/kg bw PCB 126 in corn oil. Control animals were exposed in parallel and received corn oil alone. Lipids were extracted from whole liver homogenate and levels of polar lipids and fatty acids incorporated into triglycerides (FATAGs) were determined with tandem mass spectrometry using electrospray ionization. PCB 126 exposure increased the hepatic content of polar lipids and FATAGs. Protein adjusted levels of several polar lipid classes, in particular phosphatidylserine levels, decreased, whereas FATAGs levels typically increased with increasing PCB 126 dose. Sensitive, dose-dependent endpoints of PCB 126 exposure included an increase in levels of adrenic acid incorporated into triglycerides and changes in levels of certain ether-linked phospholipid and 1-alkyl/1-alkenyldiacylglycerol species, as determined using partial least square discriminant analysis (PLS-DA) and ANOVA. These changes in the composition of polar lipids and fatty acid in the liver of PCB 126 exposed rats identified several novel markers of PCB 126-mediated fatty liver disease that need to be validated in further studies.
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Affiliation(s)
- Izabela Kania-Korwel
- Department of Occupational Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, USA
| | - Xianai Wu
- Department of Occupational Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, USA
| | - Kai Wang
- Department of Biostatistics, College of Public Health, The University of Iowa, Iowa City, IA, USA
| | - Hans-Joachim Lehmler
- Department of Occupational Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, USA.
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41
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Nadal A, Quesada I, Tudurí E, Nogueiras R, Alonso-Magdalena P. Endocrine-disrupting chemicals and the regulation of energy balance. Nat Rev Endocrinol 2017; 13:536-546. [PMID: 28524168 DOI: 10.1038/nrendo.2017.51] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Energy balance involves the adjustment of food intake, energy expenditure and body fat reserves through homeostatic pathways. These pathways include a multitude of biochemical reactions, as well as hormonal cues. Dysfunction of this homeostatic control system results in common metabolism-related pathologies, which include obesity and type 2 diabetes mellitus. Metabolism-disrupting chemicals (MDCs) are a particular class of endocrine-disrupting chemicals that affect energy homeostasis. MDCs affect multiple endocrine mechanisms and thus different cell types that are implicated in metabolic control. MDCs affect gene expression and the biosynthesis of key enzymes, hormones and adipokines that are essential for controlling energy homeostasis. This multifaceted spectrum of actions precludes compensatory responses and favours metabolic disorders. Herein, we review the main mechanisms used by MDCs to alter energy balance. This work should help to identify new MDCs, as well as novel targets of their action.
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Affiliation(s)
- Angel Nadal
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Avda Universidad s/n, 03202 Elche, Alicante, Spain
| | - Ivan Quesada
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Avda Universidad s/n, 03202 Elche, Alicante, Spain
| | - Eva Tudurí
- Instituto de Investigaciones Sanitarias (IDIS), Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS) and Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (CIBERobn), Avda. Barcelona s/n, 15706 Santiago de Compostela, Spain
| | - Rubén Nogueiras
- Instituto de Investigaciones Sanitarias (IDIS), Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS) and Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (CIBERobn), Avda. Barcelona s/n, 15706 Santiago de Compostela, Spain
- Department of Physiology, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), University of Santiago de Compostela, Calle San Francisco s/n, 15706 Santiago de Compostela, Spain
| | - Paloma Alonso-Magdalena
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Avda Universidad s/n, 03202 Elche, Alicante, Spain
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2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-elicited effects on bile acid homeostasis: Alterations in biosynthesis, enterohepatic circulation, and microbial metabolism. Sci Rep 2017; 7:5921. [PMID: 28725001 PMCID: PMC5517430 DOI: 10.1038/s41598-017-05656-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/01/2017] [Indexed: 01/14/2023] Open
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant which elicits hepatotoxicity through activation of the aryl hydrocarbon receptor (AhR). Male C57BL/6 mice orally gavaged with TCDD (0.01–30 µg/kg) every 4 days for 28 days exhibited bile duct proliferation and pericholangitis. Mass spectrometry analysis detected a 4.6-fold increase in total hepatic bile acid levels, despite the coordinated repression of genes involved in cholesterol and primary bile acid biosynthesis including Cyp7a1. Specifically, TCDD elicited a >200-fold increase in taurolithocholic acid (TLCA), a potent G protein-coupled bile acid receptor 1 (GPBAR1) agonist associated with bile duct proliferation. Increased levels of microbial bile acid metabolism loci (bsh, baiCD) are consistent with accumulation of TLCA and other secondary bile acids. Fecal bile acids decreased 2.8-fold, suggesting enhanced intestinal reabsorption due to induction of ileal transporters (Slc10a2, Slc51a) and increases in whole gut transit time and intestinal permeability. Moreover, serum bile acids were increased 45.4-fold, consistent with blood-to-hepatocyte transporter repression (Slco1a1, Slc10a1, Slco2b1, Slco1b2, Slco1a4) and hepatocyte-to-blood transporter induction (Abcc4, Abcc3). These results suggest that systemic alterations in enterohepatic circulation, as well as host and microbiota bile acid metabolism, favor bile acid accumulation that contributes to AhR-mediated hepatotoxicity.
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Nault R, Fader KA, Lydic TA, Zacharewski TR. Lipidomic Evaluation of Aryl Hydrocarbon Receptor-Mediated Hepatic Steatosis in Male and Female Mice Elicited by 2,3,7,8-Tetrachlorodibenzo-p-dioxin. Chem Res Toxicol 2017; 30:1060-1075. [PMID: 28238261 PMCID: PMC5896278 DOI: 10.1021/acs.chemrestox.6b00430] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces hepatic steatosis mediated by the aryl hydrocarbon receptor. To further characterize TCDD-elicited hepatic lipid accumulation, mice were gavaged with TCDD every 4 days for 28 days. Liver samples were examined using untargeted lipidomics with structural confirmation of lipid species by targeted high-resolution MS/MS, and data were integrated with complementary RNA-Seq analyses. Approximately 936 unique spectral features were detected, of which 379 were confirmed as unique lipid species. Both male and female samples exhibited similar qualitative changes (lipid species) but differed in quantitative changes. A shift to higher mass lipid species was observed, indicative of increased free fatty acid (FFA) packaging. For example, of the 13 lipid classes examined, triglycerides increased from 46 to 48% of total lipids to 68-83% in TCDD treated animals. Hepatic cholesterol esters increased 11.3-fold in male mice with moieties consisting largely of dietary fatty acids (FAs) (i.e., linolenate, palmitate, and oleate). Phosphatidylserines, phosphatidylethanolamines, phosphatidic acids, and cardiolipins decreased 4.1-, 5.0-, 5.4- and 7.4-fold, respectively, while ceramides increased 6.6-fold. Accordingly, the integration of lipidomic data with differential gene expression associated with lipid metabolism suggests that in addition to the repression of de novo fatty acid synthesis and β-oxidation, TCDD also increased hepatic uptake and packaging of lipids, while inhibiting VLDL secretion, consistent with hepatic fat accumulation and the progression to steatohepatitis with fibrosis.
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Affiliation(s)
- Rance Nault
- Biochemistry & Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Kelly A. Fader
- Biochemistry & Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Todd A. Lydic
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Timothy R. Zacharewski
- Biochemistry & Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, United States
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Heindel JJ, Blumberg B, Cave M, Machtinger R, Mantovani A, Mendez MA, Nadal A, Palanza P, Panzica G, Sargis R, Vandenberg LN, Vom Saal F. Metabolism disrupting chemicals and metabolic disorders. Reprod Toxicol 2017; 68:3-33. [PMID: 27760374 PMCID: PMC5365353 DOI: 10.1016/j.reprotox.2016.10.001] [Citation(s) in RCA: 629] [Impact Index Per Article: 89.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/04/2016] [Accepted: 10/13/2016] [Indexed: 01/09/2023]
Abstract
The recent epidemics of metabolic diseases, obesity, type 2 diabetes(T2D), liver lipid disorders and metabolic syndrome have largely been attributed to genetic background and changes in diet, exercise and aging. However, there is now considerable evidence that other environmental factors may contribute to the rapid increase in the incidence of these metabolic diseases. This review will examine changes to the incidence of obesity, T2D and non-alcoholic fatty liver disease (NAFLD), the contribution of genetics to these disorders and describe the role of the endocrine system in these metabolic disorders. It will then specifically focus on the role of endocrine disrupting chemicals (EDCs) in the etiology of obesity, T2D and NAFLD while finally integrating the information on EDCs on multiple metabolic disorders that could lead to metabolic syndrome. We will specifically examine evidence linking EDC exposures during critical periods of development with metabolic diseases that manifest later in life and across generations.
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Affiliation(s)
- Jerrold J Heindel
- National Institute of Environmental Health Sciences, Division of Extramural Research and Training Research Triangle Park, NC, USA.
| | - Bruce Blumberg
- University of California, Department of Developmental and Cell Biology, Irvine CA, USA
| | - Mathew Cave
- University of Louisville, Division of Gastroenterology, Hepatology and Nutrition, Louisville KY, USA
| | | | | | - Michelle A Mendez
- University of North Carolina at Chapel Hill, School of Public Health, Chapel Hill NC, USA
| | - Angel Nadal
- Institute of Bioengineering and CIBERDEM, Miguel Hernandez University of Elche, Elche, Alicante, Spain
| | - Paola Palanza
- University of Parma, Department of Neurosciences, Parma, Italy
| | - Giancarlo Panzica
- University of Turin, Department of Neuroscience and Neuroscience Institute Cavalieri Ottolenghi (NICO), Turin, Italy
| | - Robert Sargis
- University of Chicago, Section of Endocrinology, Diabetes and Metabolism, Department of Medicine Chicago, IL, USA
| | - Laura N Vandenberg
- University of Massachusetts, Department of Environmental Health Sciences, School of Public Health & Health Sciences, Amherst, MA, USA
| | - Frederick Vom Saal
- University of Missouri, Department of Biological Sciences, Columbia, MO, USA
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Angrish MM, Kaiser JP, McQueen CA, Chorley BN. Tipping the Balance: Hepatotoxicity and the 4 Apical Key Events of Hepatic Steatosis. Toxicol Sci 2016; 150:261-8. [PMID: 26980302 DOI: 10.1093/toxsci/kfw018] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hepatic steatosis is a condition were fat accumulates in the liver and it is associated with extra-hepatic diseases related to metabolic syndrome and systemic energy metabolism. If not reversed, steatosis can progress to steatohepatitis and irreversible stages of liver disease including fibrosis, cirrhosis, hepatocellular carcinoma, and death. From a public health standpoint, identifying chemical exposures that may be factors in steatosis etiology are important for preventing hepatotoxicity and liver disease progression. It is therefore important to identify the biological events that are key for steatosis pathology mediated by chemical exposure. In this review, we give a current overview of the complex biological cascades that can disrupt lipid homeostasis in hepatocytes in the context of 4 apical key events central to hepatic lipid retention: hepatic fatty acid (FA) uptake,de novoFA and lipid synthesis, FA oxidation, and lipid efflux. Our goal is to review these key cellular events and visually summarize them using a network for application in pathway-based toxicity testing. This effort provides a foundation to improve next-generation chemical screening efforts that may be used to prevent and ultimately reverse the growing incidence of fatty liver disease in our population.
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Affiliation(s)
- Michelle M Angrish
- *National Health and Environmental Effects Research Laboratory, Office of Research and Development (ORD), United States Environmental Protection Agency (US EPA), Research Triangle Park, North Carolina 27709
| | - Jonathan Phillip Kaiser
- United States Environmental Protection Agency (US EPA), National Center for Environmental Assessment, Office of Research and Development (ORD), Cincinnati, Ohio 45268
| | - Charlene A McQueen
- *National Health and Environmental Effects Research Laboratory, Office of Research and Development (ORD), United States Environmental Protection Agency (US EPA), Research Triangle Park, North Carolina 27709
| | - Brian N Chorley
- *National Health and Environmental Effects Research Laboratory, Office of Research and Development (ORD), United States Environmental Protection Agency (US EPA), Research Triangle Park, North Carolina 27709;
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Fader KA, Nault R, Ammendolia DA, Harkema JR, Williams KJ, Crawford RB, Kaminski NE, Potter D, Sharratt B, Zacharewski TR. 2,3,7,8-Tetrachlorodibenzo-p-Dioxin Alters Lipid Metabolism and Depletes Immune Cell Populations in the Jejunum of C57BL/6 Mice. Toxicol Sci 2015; 148:567-80. [PMID: 26377647 PMCID: PMC5009443 DOI: 10.1093/toxsci/kfv206] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent aryl hydrocarbon receptor agonist that elicits dose-dependent hepatic fat accumulation and inflammation that can progress to steatohepatitis. To investigate intestine-liver interactions that contribute to TCDD-elicited steatohepatitis, we examined the dose-dependent effects of TCDD (0.01, 0.03, 0.1, 0.3, 1, 3, 10, or 30 µg/kg) on jejunal epithelial gene expression in C57BL/6 mice orally gavaged every 4 days for 28 days. Agilent 4x44K whole-genome microarray analysis of the jejunal epithelium identified 439 differentially expressed genes (|fold change| ≥ 1.5, P1(t) ≥ 0.999) across 1 or more doses, many related to lipid metabolism and immune system processes. TCDD-elicited differentially expressed genes were associated with lipolysis, fatty acid/cholesterol absorption and transport, the Kennedy pathway, and retinol metabolism, consistent with increased hepatic fat accumulation. Moreover, several major histocompatibility complex (MHC) class II genes (H2-Aa, H2-Ab1, H2-DMb1, Cd74) were repressed, coincident with decreased macrophage and dendritic cell levels in the lamina propria, suggesting migration of antigen-presenting cells out of the intestine. In contrast, hepatic RNA-Seq analysis identified increased expression of MHC class II genes, as well as chemokines and chemokine receptors involved in macrophage recruitment (Ccr1, Ccr5, Ccl5, Cx3cr1), consistent with hepatic F4/80 labeling and macrophage infiltration into the liver. Collectively, these results suggest TCDD elicits changes that support hepatic lipid accumulation, macrophage migration, and the progression of hepatic steatosis to steatohepatitis.
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Affiliation(s)
- Kelly A Fader
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824; Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
| | - Rance Nault
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824; Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
| | - Dustin A Ammendolia
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Jack R Harkema
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824; Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan 48824
| | - Kurt J Williams
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan 48824
| | - Robert B Crawford
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824; and
| | - Norbert E Kaminski
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824; and
| | - Dave Potter
- Wellington Laboratories Inc., Guelph, Ontario N1G 3M5, Canada
| | - Bonnie Sharratt
- Wellington Laboratories Inc., Guelph, Ontario N1G 3M5, Canada
| | - Timothy R Zacharewski
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824; *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824;
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Nault R, Fader KA, Kirby MP, Ahmed S, Matthews J, Jones AD, Lunt SY, Zacharewski TR. Pyruvate Kinase Isoform Switching and Hepatic Metabolic Reprogramming by the Environmental Contaminant 2,3,7,8-Tetrachlorodibenzo-p-Dioxin. Toxicol Sci 2015; 149:358-71. [PMID: 26582802 DOI: 10.1093/toxsci/kfv245] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) elicits dose-dependent hepatotoxicity that includes fat accumulation, inflammation, and fibrosis that may progress to hepatocellular carcinoma. To further investigate these effects, RNA-Seq data were integrated with computationally identified putative dioxin response elements, and complementary targeted metabolomic and aryl hydrocarbon receptor (AhR) ChIP-Seq data from female C57BL/6 mice gavaged with TCDD every 4 days for 28 days. Data integration using CytoKEGG with manual curation identified dose-dependent alterations in central carbon and amino acid metabolism. More specifically, TCDD increased pyruvate kinase isoform M2 (PKM2) gene and protein expression. PKM2 has lower catalytic activity resulting in decreased glycolytic flux and the accumulation of upstream intermediates that were redirected to the pentose phosphate pathway and serine/folate biosynthesis, 2 important NADPH producing pathways stemming from glycolysis. In addition, the GAC:KGA glutaminase (GLS1) protein isoform ratio was increased, consistent with increases in glutaminolysis which serves an anaplerotic role for the TCA cycle and compensates for the reduced glycolytic flux. Collectively, gene expression, protein, and metabolite changes were indicative of increases in NADPH production in support of cytochrome P450 activity and ROS defenses. This AhR-mediated metabolic reprogramming is similar to the Warburg effect and represents a novel advantageous defense mechanism to increase anti-oxidant capacity in normal differentiated hepatocytes.
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Affiliation(s)
- Rance Nault
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, Institute for Integrative Toxicology
| | - Kelly A Fader
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, Institute for Integrative Toxicology
| | - Mathew P Kirby
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Shaimaa Ahmed
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Jason Matthews
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada, Department of Nutrition, University of Oslo, Oslo, 0316, Norway, and
| | - A Daniel Jones
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
| | - Sophia Y Lunt
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Timothy R Zacharewski
- *Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, Institute for Integrative Toxicology,
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Zhang L, Hatzakis E, Nichols RG, Hao R, Correll J, Smith PB, Chiaro CR, Perdew GH, Patterson AD. Metabolomics Reveals that Aryl Hydrocarbon Receptor Activation by Environmental Chemicals Induces Systemic Metabolic Dysfunction in Mice. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:8067-77. [PMID: 26023891 PMCID: PMC4890155 DOI: 10.1021/acs.est.5b01389] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Environmental exposure to dioxins and dioxin-like compounds poses a significant health risk for human health. Developing a better understanding of the mechanisms of toxicity through activation of the aryl hydrocarbon receptor (AHR) is likely to improve the reliability of risk assessment. In this study, the AHR-dependent metabolic response of mice exposed to 2,3,7,8-tetrachlorodibenzofuran (TCDF) was assessed using global (1)H nuclear magnetic resonance (NMR)-based metabolomics and targeted metabolite profiling of extracts obtained from serum and liver. (1)H NMR analyses revealed that TCDF exposure suppressed gluconeogenesis and glycogenolysis, stimulated lipogenesis, and triggered inflammatory gene expression in an Ahr-dependent manner. Targeted analyses using gas chromatography coupled with mass spectrometry showed TCDF treatment altered the ratio of unsaturated/saturated fatty acids. Consistent with this observation, an increase in hepatic expression of stearoyl coenzyme A desaturase 1 was observed. In addition, TCDF exposure resulted in inhibition of de novo fatty acid biosynthesis manifested by down-regulation of acetyl-CoA, malonyl-CoA, and palmitoyl-CoA metabolites and related mRNA levels. In contrast, no significant changes in the levels of glucose and lipid were observed in serum and liver obtained from Ahr-null mice following TCDF treatment, thus strongly supporting the important role of the AHR in mediating the metabolic effects seen following TCDF exposure.
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Affiliation(s)
- Limin Zhang
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences (CAS), Wuhan 430071, China
| | - Emmanuel Hatzakis
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Robert G. Nichols
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Ruixin Hao
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Jared Correll
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Philip B. Smith
- Metabolomics Facility, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Christopher R. Chiaro
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Gary H. Perdew
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Andrew D. Patterson
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
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Zhang L, Nichols RG, Correll J, Murray IA, Tanaka N, Smith PB, Hubbard TD, Sebastian A, Albert I, Hatzakis E, Gonzalez FJ, Perdew GH, Patterson AD. Persistent Organic Pollutants Modify Gut Microbiota-Host Metabolic Homeostasis in Mice Through Aryl Hydrocarbon Receptor Activation. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:679-88. [PMID: 25768209 PMCID: PMC4492271 DOI: 10.1289/ehp.1409055] [Citation(s) in RCA: 227] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 03/09/2015] [Indexed: 05/04/2023]
Abstract
BACKGROUND Alteration of the gut microbiota through diet and environmental contaminants may disturb physiological homeostasis, leading to various diseases including obesity and type 2 diabetes. Because most exposure to environmentally persistent organic pollutants (POPs) occurs through the diet, the host gastrointestinal tract and commensal gut microbiota are likely to be exposed to POPs. OBJECTIVES We examined the effect of 2,3,7,8-tetrachlorodibenzofuran (TCDF), a persistent environmental contaminant, on gut microbiota and host metabolism, and we examined correlations between gut microbiota composition and signaling pathways. METHODS Six-week-old male wild-type and Ahr-/- mice on the C57BL/6J background were treated with 24 μg/kg TCDF in the diet for 5 days. We used 16S rRNA gene sequencing, 1H nuclear magnetic resonance (NMR) metabolomics, targeted ultra-performance liquid chromatography coupled with triplequadrupole mass spectrometry, and biochemical assays to determine the microbiota compositions and the physiological and metabolic effects of TCDF. RESULTS Dietary TCDF altered the gut microbiota by shifting the ratio of Firmicutes to Bacteroidetes. TCDF-treated mouse cecal contents were enriched with Butyrivibrio spp. but depleted in Oscillobacter spp. compared with vehicle-treated mice. These changes in the gut microbiota were associated with altered bile acid metabolism. Further, dietary TCDF inhibited the farnesoid X receptor (FXR) signaling pathway, triggered significant inflammation and host metabolic disorders as a result of activation of bacterial fermentation, and altered hepatic lipogenesis, gluconeogenesis, and glycogenolysis in an AHR-dependent manner. CONCLUSION These findings provide new insights into the biochemical consequences of TCDF exposure involving the alteration of the gut microbiota, modulation of nuclear receptor signaling, and disruption of host metabolism.
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Affiliation(s)
- Limin Zhang
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
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Angrish MM, Madden MC, Pleil JD. Probe molecule (PrM) approach in adverse outcome pathway (AOP) based high-throughput screening (HTS): in vivo discovery for developing in vitro target methods. Chem Res Toxicol 2015; 28:551-9. [PMID: 25692543 DOI: 10.1021/acs.chemrestox.5b00024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Efficient and accurate adverse outcome pathway (AOP) based high-throughput screening (HTS) methods use a systems biology based approach to computationally model in vitro cellular and molecular data for rapid chemical prioritization; however, not all HTS assays are grounded by relevant in vivo exposure data. The challenge is to develop HTS assays with unambiguous quantitative links between in vitro responses and corresponding in vivo effects, which is complicated by metabolically insufficient systems, in vitro to in vivo extrapolation (IVIVE), cross-species comparisons, and other inherent issues correlating IVIVE findings. This article introduces the concept of ultrasensitive gas phase probe molecules (PrMs) to help bridge the current HTS assay IVIVE gap. The PrM concept assesses metabolic pathways that have already been well-defined from intact human or mammalian models. Specifically, the idea is to introduce a gas phase probe molecule into a system, observe normal steady state, add chemicals of interest, and quantitatively measure (from headspace gas) effects on PrM metabolism that can be directly linked back to a well-defined and corresponding in vivo effect. As an example, we developed the pharmacokinetic (PK) parameters and differential equations to estimate methyl tertiary butyl ether (MTBE) metabolism to tertiary butyl alcohol (TBA) via cytochrome (CYP) 2A6 in the liver from human empirical data. Because MTBE metabolic pathways are well characterized from in vivo data, we can use it as a PrM to explore direct and indirect chemical effects on CYP pathways. The PrM concept could be easily applied to in vitro and alternative models of disease and phenotype, and even test for volatile chemicals while avoiding liquid handling robotics. Furthermore, a PrM can be designed for any chemical with known empirical human exposure data and used to assess chemicals for which no information exists. Herein, we propose an elegant gas phase probe molecule-based approach to in vitro toxicity testing.
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Affiliation(s)
- Michelle M Angrish
- †ORISE Participant, US EPA, Research Triangle Park, North Carolina 27711, United States
| | - Michael C Madden
- ‡Environmental Public Health Division, NHEERL/ORD, US EPA, Chapel Hill, North Carolina 27599, United States
| | - Joachim D Pleil
- §Human Exposure and Atmospheric Sciences Division, NERL/ORD, US EPA, Research Triangle Park, North Carolina 27711, United States
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