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He J, Yu M, Chi C, Du Z, Zheng Y, Chen C, Moawad AS, Song C, Wang X. Insertion of 643bp Retrotransposon Upstream of PPARγ CDS Is Associated with Backfat of Large White Pigs. Animals (Basel) 2023; 13:2355. [PMID: 37508132 PMCID: PMC10376311 DOI: 10.3390/ani13142355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/16/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
PPARs are essential regulators of mammalian fatty acid and lipid metabolism. Although the effects of genetic variations, including single nucleotide polymorphisms (SNPs) in PPARs genes on the phenotype of domestic animals have been investigated, there is limited information on the impact of retrotransposon insertion polymorphisms (RIPs). In this study, a combined comparative genome and polymerase chain reaction (PCR) was used to excavate the RIPs in porcine PPARs. We also investigated the potential effects of retrotransposon insertion on phenotype and expression patterns. This study identified the two RIPs in PPARs genes, namely an ERV in intron 1 of PPARα and a combined retrotransposon in intron 2 of PPARγ, designated as PPARα-ERV-RIP and PPARγ-COM-RIP, respectively. These RIPs exhibited different distribution patterns among Chinese indigenous breeds and Western commercial breeds. Individuals with the PPARα-ERV-RIP+/+ genotype (+/+ indicated homozygous with insertion) among Large White pigs had significantly higher (p < 0.05) corrected backfat thickness compared to those with the other two genotypes. Similarly, those with the PPARγ-COM-RIP-/- genotype had significantly higher (p < 0.05) corrected backfat thickness than those with the other two genotypes in Large White pigs. Moreover, in 30-day-old Sujiang piglets, the PPARγ gene expression in the backfat of those with the PPARγ-COM-RIP-/- genotype (-/- indicated homozygous without insertion) was significantly greater (p < 0.01) than those with other genotypes. The dual luciferase reporter gene assay demonstrated that the combined retrotransposon insertion significantly reduced the activity of the MYC promoter in both C2C12 and 3T3-L1 cells (p < 0.01). Therefore, the combined retrotransposon insertion could function as a repressor to decrease the expression of PPARγ, making PPARγ-COM-RIP a valuable molecular marker for assisted selection of backfat thickness in pig breeding.
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Affiliation(s)
- Jia He
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Miao Yu
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Chenglin Chi
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Zhanyu Du
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Yao Zheng
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Cai Chen
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Ali Shoaib Moawad
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
- Department of Animal Production, Faculty of Agriculture, Kafrelsheikh University, Kafrelsheikh 33516, Egypt
| | - Chengyi Song
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Xiaoyan Wang
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
- International Joint Research Laboratory in Universities of Jiangsu Province of China for Domestic Animal Germplasm Resources and Genetic Improvement, Yangzhou 225009, China
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Peroxisome Proliferator-Activated Receptor-Targeted Therapies: Challenges upon Infectious Diseases. Cells 2023; 12:cells12040650. [PMID: 36831317 PMCID: PMC9954612 DOI: 10.3390/cells12040650] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) α, β, and γ are nuclear receptors that orchestrate the transcriptional regulation of genes involved in a variety of biological responses, such as energy metabolism and homeostasis, regulation of inflammation, cellular development, and differentiation. The many roles played by the PPAR signaling pathways indicate that PPARs may be useful targets for various human diseases, including metabolic and inflammatory conditions and tumors. Accumulating evidence suggests that each PPAR plays prominent but different roles in viral, bacterial, and parasitic infectious disease development. In this review, we discuss recent PPAR research works that are focused on how PPARs control various infections and immune responses. In addition, we describe the current and potential therapeutic uses of PPAR agonists/antagonists in the context of infectious diseases. A more comprehensive understanding of the roles played by PPARs in terms of host-pathogen interactions will yield potential adjunctive personalized therapies employing PPAR-modulating agents.
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Medical devices as a source of phthalate exposure: a review of current knowledge and alternative solutions. Arh Hig Rada Toksikol 2022; 73:179-190. [PMID: 36226817 PMCID: PMC9837533 DOI: 10.2478/aiht-2022-73-3639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/01/2022] [Indexed: 11/07/2022] Open
Abstract
Phthalates are a group of phthalic acid esters used as plasticisers in a large number of products to improve their flexibility, softness, and extensibility. Their wide use in medical devices, however, raises a lot of concern, as they can enter the organism and have toxic effects on human liver, thyroid, kidneys, lungs, reproductive, endocrine, nervous, and respiratory system and are associated with asthma, obesity, autism, and diabetes. The aim of this review is to summarise current knowledge about phthalate migration from medical devices during different medical procedures and possible impact on patient health. It also looks at alternative plasticisers with supposedly lower migration rates and safer profile. Not enough is known about which and how many phthalates make part of medical devices or about the health impacts of alternative plasticisers or their migration rates.
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Dumas T, Courant F, Almunia C, Boccard J, Rosain D, Duporté G, Armengaud J, Fenet H, Gomez E. An integrated metabolomics and proteogenomics approach reveals molecular alterations following carbamazepine exposure in the male mussel Mytilus galloprovincialis. CHEMOSPHERE 2022; 286:131793. [PMID: 34364230 DOI: 10.1016/j.chemosphere.2021.131793] [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: 04/02/2021] [Revised: 07/05/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
Carbamazepine is one of the most abundant pharmaceutical active compounds detected in aquatic systems. Based on laboratory exposures, carbamazepine has been proven to adversely affect aquatic organisms. However, the underlying molecular events remain poorly understood. This study aims to investigate the molecular mechanisms potentially associated with toxicological effects of carbamazepine on the mussel Mytilus galloprovincialis exposed for 3 days at realistic concentrations encountered in coastal environments (80 ng/L and 8 μg/L). An integrated metabolomics and proteogenomics approach, including data fusion strategy, was applied to gain more insight in molecular events and cellular processes triggered by carbamazepine exposure. Consistent metabolic and protein signatures revealed a metabolic rewiring and cellular stress at both concentrations (e.g. intensification of protein synthesis, transport and catabolism processes, disruption of lipid and amino acid metabolisms). These highlighted molecular signatures point to the induction of autophagy, closely related with carbamazepine mechanism of action, as well as a destabilization of the lysosomal membranes and an enzymatic overactivity of the peroxisomes. Induction of programmed cell death was highlighted by the modulation of apoptotic cognate proteins. The proposed integrative omics data analysis was shown to be highly relevant to identify the modulations of the two molecular levels, i.e. metabolites and proteins. Multi-omics approach is able to explain the resulting complex biological system, and document stronger toxicological pieces of evidence on pharmaceutical active compounds at environmental concentrations in sentinel organisms.
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Affiliation(s)
- Thibaut Dumas
- HydroSciences Montpellier, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Frédérique Courant
- HydroSciences Montpellier, IRD, CNRS, University of Montpellier, Montpellier, France.
| | - Christine Almunia
- Université Paris-Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, 30200, Bagnols-sur-Cèze, France
| | - Julien Boccard
- School of Pharmaceutical Sciences, University of Geneva, Geneva, 1211, Switzerland; Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Geneva, 1211, Switzerland
| | - David Rosain
- HydroSciences Montpellier, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Geoffroy Duporté
- HydroSciences Montpellier, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Jean Armengaud
- Université Paris-Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, 30200, Bagnols-sur-Cèze, France
| | - Hélène Fenet
- HydroSciences Montpellier, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Elena Gomez
- HydroSciences Montpellier, IRD, CNRS, University of Montpellier, Montpellier, France
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Dixit G, Prabhu A. The pleiotropic peroxisome proliferator activated receptors: Regulation and therapeutics. Exp Mol Pathol 2021; 124:104723. [PMID: 34822814 DOI: 10.1016/j.yexmp.2021.104723] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 02/07/2023]
Abstract
The Peroxisome proliferator-activated receptors (PPARs) are key regulators of metabolic events in our body. Owing to their implication in maintenance of homeostasis, both PPAR agonists and antagonists assume therapeutic significance. Understanding the molecular mechanisms of each of the PPAR isotypes in the healthy body and during disease is crucial to exploiting their full therapeutic potential. This article is an attempt to present a rational analysis of the multifaceted therapeutic effects and underlying mechanisms of isotype-specific PPAR agonists, dual PPAR agonists, pan PPAR agonists as well as PPAR antagonists. A holistic understanding of the mechanistic dimensions of these key metabolic regulators will guide future efforts to identify novel molecules in the realm of metabolic, inflammatory and immunotherapeutic diseases.
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Affiliation(s)
- Gargi Dixit
- Department of Pharmaceutical Chemistry & Quality Assurance, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai, India
| | - Arati Prabhu
- Department of Pharmaceutical Chemistry & Quality Assurance, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai, India.
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Tahri-Joutey M, Andreoletti P, Surapureddi S, Nasser B, Cherkaoui-Malki M, Latruffe N. Mechanisms Mediating the Regulation of Peroxisomal Fatty Acid Beta-Oxidation by PPARα. Int J Mol Sci 2021; 22:ijms22168969. [PMID: 34445672 PMCID: PMC8396561 DOI: 10.3390/ijms22168969] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/14/2021] [Accepted: 08/15/2021] [Indexed: 12/12/2022] Open
Abstract
In mammalian cells, two cellular organelles, mitochondria and peroxisomes, share the ability to degrade fatty acid chains. Although each organelle harbors its own fatty acid β-oxidation pathway, a distinct mitochondrial system feeds the oxidative phosphorylation pathway for ATP synthesis. At the same time, the peroxisomal β-oxidation pathway participates in cellular thermogenesis. A scientific milestone in 1965 helped discover the hepatomegaly effect in rat liver by clofibrate, subsequently identified as a peroxisome proliferator in rodents and an activator of the peroxisomal fatty acid β-oxidation pathway. These peroxisome proliferators were later identified as activating ligands of Peroxisome Proliferator-Activated Receptor α (PPARα), cloned in 1990. The ligand-activated heterodimer PPARα/RXRα recognizes a DNA sequence, called PPRE (Peroxisome Proliferator Response Element), corresponding to two half-consensus hexanucleotide motifs, AGGTCA, separated by one nucleotide. Accordingly, the assembled complex containing PPRE/PPARα/RXRα/ligands/Coregulators controls the expression of the genes involved in liver peroxisomal fatty acid β-oxidation. This review mobilizes a considerable number of findings that discuss miscellaneous axes, covering the detailed expression pattern of PPARα in species and tissues, the lessons from several PPARα KO mouse models and the modulation of PPARα function by dietary micronutrients.
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Affiliation(s)
- Mounia Tahri-Joutey
- Bio-PeroxIL Laboratory, University of Bourgogne Franche-Comté, 21000 Dijon, France; (M.T.-J.); (P.A.); (M.C.-M.)
- Laboratory of Biochemistry, Neurosciences, Natural Resources and Environment, Faculty of Sciences & Techniques, University Hassan I, BP 577, 26000 Settat, Morocco;
| | - Pierre Andreoletti
- Bio-PeroxIL Laboratory, University of Bourgogne Franche-Comté, 21000 Dijon, France; (M.T.-J.); (P.A.); (M.C.-M.)
| | - Sailesh Surapureddi
- Office of Pollution Prevention and Toxics, United States Environmental Protection Agency, Washington, DC 20460, USA;
| | - Boubker Nasser
- Laboratory of Biochemistry, Neurosciences, Natural Resources and Environment, Faculty of Sciences & Techniques, University Hassan I, BP 577, 26000 Settat, Morocco;
| | - Mustapha Cherkaoui-Malki
- Bio-PeroxIL Laboratory, University of Bourgogne Franche-Comté, 21000 Dijon, France; (M.T.-J.); (P.A.); (M.C.-M.)
| | - Norbert Latruffe
- Bio-PeroxIL Laboratory, University of Bourgogne Franche-Comté, 21000 Dijon, France; (M.T.-J.); (P.A.); (M.C.-M.)
- Correspondence:
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Miura H, Mizuguchi H, Amano-Iwashita M, Maeda-Kogure R, Negishi A, Sakai A, Toyama T, Kawai H, Mitsumoto A, Kudo N. Clofibric acid increases molecular species of phosphatidylethanolamine containing arachidonic acid for biogenesis of peroxisomal membranes in peroxisome proliferation in the liver. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158963. [PMID: 33945875 DOI: 10.1016/j.bbalip.2021.158963] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/22/2021] [Accepted: 04/28/2021] [Indexed: 01/22/2023]
Abstract
The biogenesis of peroxisomes in relation to the trafficking of proteins to peroxisomes has been extensively examined. However, the supply of phospholipids, which is needed to generate peroxisomal membranes in mammals, remains unclear. Therefore, we herein investigated metabolic alterations induced by clofibric acid, a peroxisome proliferator, in the synthesis of phospholipids, particularly phosphatidylethanolamine (PE) molecular species, and their relationship with the biogenesis of peroxisomal membranes. The subcutaneous administration of clofibric acid to rats at a relatively low dose (130 mg/kg) once a day time-dependently and gradually increased the integrated perimeter of peroxisomes per 100 μm2 hepatocyte cytoplasm (PA). A strong correlation was observed between the content (μmol/mg DNA) of PE containing arachidonic acid (20:4) and PA (r2 = 0.9168). Moreover, the content of PE containing octadecenoic acid (18:1) positively correlated with PA (r2 = 0.8094). The treatment with clofibric acid markedly accelerated the formation of 16:0-20:4 PE by increasing the production of 20:4 and the activity of acyl chain remodeling of pre-existing PE molecular species. Increases in the acyl chain remodeling of PE by clofibric acid were mainly linked to the up-regulated expression of the Lpcat3 gene. On the other hand, clofibric acid markedly increased the formation of palmitic acid (16:0)-18:1 PE through de novo synthesis. These results suggest that the enhanced formation of particular PE molecular species is related to increases in the mass of peroxisomal membranes in peroxisome proliferation in the liver.
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Affiliation(s)
- Hiroaki Miura
- Research and Development Laboratories, Maruho Co., 1 Awatacho, Chudoji, Shimogyo-ku, Kyoto 600-8815, Japan
| | - Hiroki Mizuguchi
- School of Pharmacy and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Mino Amano-Iwashita
- School of Pharmacy and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Rie Maeda-Kogure
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan
| | - Akio Negishi
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan
| | - Ayako Sakai
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan
| | - Tomoaki Toyama
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan
| | - Hiroshi Kawai
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan
| | - Atsushi Mitsumoto
- Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Naomi Kudo
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan.
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Lerro CC, Hofmann JN, Andreotti G, Koutros S, Parks CG, Blair A, Albert PS, Lubin JH, Sandler DP, Beane Freeman LE. Dicamba use and cancer incidence in the agricultural health study: an updated analysis. Int J Epidemiol 2021; 49:1326-1337. [PMID: 32357211 DOI: 10.1093/ije/dyaa066] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND The herbicide dicamba has been commonly used agriculturally and residentially. Recent approval of genetically engineered dicamba-resistant crops is expected to lead to increased dicamba use, and there has been growing interest in potential human health effects. A prior analysis in the Agricultural Health Study (AHS) suggested associations between dicamba and colon and lung cancer. We re-evaluated dicamba use in the AHS, including an additional 12 years and 2702 exposed cancers. METHODS The AHS is a prospective cohort of pesticide applicators in Iowa and North Carolina. At enrollment (1993-1997) and follow-up (1999-2005), participants reported dicamba use. Exposure was characterized by cumulative intensity-weighted lifetime days, including exposure lags of up to 20 years. We estimated relative risks (RR) and 95% confidence intervals (CI) using multivariable Poisson regression for incident cancers diagnosed from enrollment through 2014/2015. RESULTS Among 49 922 applicators, 26 412 (52.9%) used dicamba. Compared with applicators reporting no dicamba use, those in the highest quartile of exposure had elevated risk of liver and intrahepatic bile duct cancer (nexposed = 28, RRQ4 = 1.80, CI: 1.26-2.56, Ptrend < 0.001) and chronic lymphocytic leukaemia (CLL, nexposed = 93, RRQ4 = 1.20, CI: 0.96-1.50, Ptrend = 0.01) and decreased risk of myeloid leukaemia (nexposed = 55, RRQ4 = 0.73, CI: 0.51-1.03, Ptrend = 0.01). The associations for liver cancer and myeloid leukaemia remained after lagging exposure of up to 20 years. CONCLUSIONS With additional follow-up and exposure information, associations with lung and colon cancer were no longer apparent. In this first evaluation of liver and intrahepatic bile duct cancer, there was an association with increasing use of dicamba that persisted across lags of up to 20 years.
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Affiliation(s)
- Catherine C Lerro
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
| | - Jonathan N Hofmann
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
| | - Gabriella Andreotti
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
| | - Stella Koutros
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
| | - Christine G Parks
- Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Aaron Blair
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
| | - Paul S Albert
- Biostatistics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
| | - Jay H Lubin
- Biostatistics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
| | - Dale P Sandler
- Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Laura E Beane Freeman
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
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Radha MJ, Mahaboob Basha P. Hepatotoxic evaluation of Di- n-butyl phthalate in Wistar rats upon sub-chronic exposure: A multigenerational assessment. Toxicol Rep 2020; 7:772-778. [PMID: 32637323 PMCID: PMC7327266 DOI: 10.1016/j.toxrep.2020.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 05/11/2020] [Accepted: 06/19/2020] [Indexed: 01/24/2023] Open
Abstract
The extensive use of di--n-butyl phthalate (DBP) as a plasticizer in medical devices, personal care products, and industries, which is a major threat to humankind as it leaches out easily from the plastic matrix into the environment. Health risks posed to adults and children from the broad usage of DBP in cosmetics and infant toys observed predominantly due to repeated and prolonged exposure. Hence, this study was undertaken to evaluate the potential effect of DBP in the hepatic tissue of rats up to three generations. Wistar rats were induced at a dose of 500 mg DBP /kg body weight dissolved in olive oil by oral gavage throughout gestation (GD 6–21), lactation and post-weaning and reared by crossing intoxicated rats up to three generations. Results of the present study showed a significant increase in the relative weight of liver, while decreased levels of antioxidant enzymes viz., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and reduced glutathione (GSH) was evident in DBP treated rats at P < 0.05. Besides hepatic marker enzymes viz., alanine transaminase (ALT) and aspartate transaminase (AST) were elevated significantly in experimental rats compared to those of the control group. Furthermore, histological studies revealed congested central veins and dilated sinusoids in F1 progeny while mild to severe focal inflammatory infiltrations were evident in F2 & F3 rats. Negative correlation observed between the levels of antioxidant enzymes and transaminase activity. In brief, DBP exposure elicits oxidative stress and alters the transaminase activity levels causing damage in hepatic tissue. F3 progeny found to high vulnerability to the exposure of DBP than F2 & F1 rats.
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Affiliation(s)
- M J Radha
- Department of Zoology, Bangalore University, Bangalore-560 056, Department of Biotechnology and Genetics, Ramaiah College of Arts, Science and Commerce, Bangalore, 560 054, India
| | - P Mahaboob Basha
- Department of Zoology, Bangalore University, Bangalore, 560 056, India
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10
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Fischer FP, Machleidt C, Rettenmeier AW, Kuhlmann U, Mettang T. Plasticizers and Inhibition of Leukocyte Function in Vitro. Perit Dial Int 2020. [DOI: 10.1177/089686089801800610] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objectives To evaluate the influence of the plasticizer metabolites of di(2-ethylhexyl)phthalate (DEHP), mono(2-ethylhexyl)phthalate (ME HP), 2-ethylhexanol (2-EH), and phthalic acid (PA) on various immune functions of poly-morphonuclear blood leukocytes (PMNL) and monocytes (MN). ME HP, 2-EH, and PA are the main hydrolysis products of DE HP. Since DE HP is leached out of the plastic matrix, patients on hemodialysis and continuous ambulatory peritoneal dialysis are exposed to considerable amounts of DE HP and its metabolites. Setting Teaching hospital, Department of Nephrology. Participants Ten healthy volunteers. Measurements After incubation of leukocytes in solutions with different plasticizer concentrations, oxidative respiratory metabolism was determined by luminolenhanced chemiluminescence (CL) after stimulation with phorbol myristate acetate (PMA). Furthermore, superoxide (02) generation was measured by cytochrome c reduction. Results At pH 5.4, a dose-dependent decrease of luminol-enhanced CL response was found in all assays. For ME HP and PA the level of significance was reached at 10 mg/L and 1 mg/L, respectively. Superoxide generation by PMNL and MN at pH 5.4 was also suppressed by ME HP and PA. At pH 7.4, only a slight suppression of oxidative metabolism at higher concentrations was observed. After incubation of the cells in a solution containing all DE HP metabolites (ME HP, PA, and 2-EH), a significant suppressive effect of CL at pH 5.4 could be observed at final plasticizer concentrations of 0.5 mg/L. Conclusions A dose-dependent impairment of leukocyte oxidative metabolism at a low pH could be demonstrated. The suppressive effect was particularly marked after incubation of the cells in solutions containing a mixture of the main plasticizers. At pH 5.4, we observed a slight alteration even at concentrations very close to those that could be found in commercially available peritoneal dialysis fluids. These results might point toward a possible synergistic detrimental effect of the different DE HP metabolites on leukocyte function, with possible clinical relevance.
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Affiliation(s)
- Frank-Peter Fischer
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart,
| | - Christoph Machleidt
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart,
| | | | - Ulrich Kuhlmann
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart,
| | - Thomas Mettang
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart,
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Abstract
Objectives To evaluate the degree of exposure to and the fate of di(2-ethylhexyl)phthalate (DE HP) and its major derivatives mono(2-ethylhexyl)phthalate (ME HP), 2-ethylhexanol (2-EH), and phthalic acid (PA) in patients undergoing regular continuous ambulatory peritoneal dialysis (CAPD) during a 4-hour dwell period. Design Prospective, controlled. Setting Teaching hospital, Department of Nephrology. Participants Seven elderly patients on stable CAPD using Fresenius instruments and dialysate and 6 agematched healthy controls. Interventions During a routinely performed peritoneal equilibration test (PET), blood and dialysate samples were drawn before and 120 and 240 min after the dwell was started. In addition, blood samples were taken from a group of volunteers participating in a pharmacological study. Measurements Quantitative analysis of DE HP and its hydrolysis products was performed by selected ion-monitoring gas chromatography/mass spectrometry, operating the mass spectrometer in a combined positive and negative ion chemical ionization mode. Results Serum concentrations of DE HP and PA were significantly higher in patients (median: 0.079 I1g/mL, range: 0.032 -0.210 I1g/mL; and 0.167 I1g/mL, range: 0.097 0.231 I1g/mL, respectively) than in controls [0.0195 I1g/mL, range: 0.016 -0.025I1g/mL (p = 0.0027) and 0.0120 I1g/mL, range: 0.006 -0.034I1g/mL (p = 0.0026), respectively]. Concentration of ME HP in the fluid of CAPD bags prior to use was four times higher than that of the parent compound. During the first 4 hours of dwell time, the concentrations of ME HP and 2-EH in dialysate consistently decreased from 0.177 (range: 0.137 -0.239119/ mL) to 0.022 I1g/mL (range: 0.005 -0.058 I1g/mL) (p = 0.017), and from 0.087 (range: 0.075 -0.097I1g/mL) to 0.05 I1g/mL (range: 0.023 0.064I1g/mL) (p = 0.017), respectively, while the concentration of DE HP remained stable. Remarkably high concentrations of PA (0.129 I1g/mL; range: 0.038 -0.466 I1g/mL) were found in CAPD bags prior to use, and these concentrations tended to increase during dwell time, without statistical significance, however (0.135I1g/mL; range: 0.073 -0.659I1g/mL, p = 0.062). Conclusions Patients on CAPD are regularly exposed to considerable amounts of phthalic ester derivatives, mainly to MEHPand PA. ME HP seems to bewellabsorbed by the peritoneal membrane. The long-term effects of this exposure remain to be elucidated.
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Mettang T, Pauli–Magnus C, Alscher DM, Kirchgessner J, Wodarz R, Rettenmeier AW, Kuhlmann U. Influence of Plasticizer-Free CAPD Bags and Tubings on Serum, Urine, and Dialysate Levels of Phthalic Acid Esters in CAPD Patients. Perit Dial Int 2020. [DOI: 10.1177/089686080002000115] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objectives To evaluate the impact of a plasticizer-free device on exposure to di-(2-ethylhexyl) phthalate (DEHP) and its major metabolites in patients on continuous ambulatory peritoneal dialysis (CAPD). DEHP is the most commonly used plasticizer in polyvinyl chloride (PVC) products; it is added to CAPD bags in order to improve the flexibility of the material. Since DEHP leaches out of the plastic matrix, patients on CAPD are exposed to considerable amounts of DEHP and its metabolites. Design A prospective cross-over study. Setting Department of nephrology in a teaching hospital. Participants Six patients (4 female, 2 male) stable on peritoneal dialysis (PD) for at least 6 months. Interventions Patients were switched from a plasticizer-containing PVC CAPD system (A.N.D.Y. Plus, Fresenius Medical Care, Bad Homburg, Germany) to a polyolefine-made plasticizer-free system (stay-safe, Fresenius). Main Outcome Measures Prior to and 42 days after the switch, 24-hour effluent dialysate and urine collections were performed and 10 mL blood was drawn. Concentrations of DEHP, mono-(2-ethylhexyl) phthalate (MEHP), phthalic acid (PA), and 2-ethylhexanol (2-EH) in urine, dialysate, and serum were determined using gas chromatography/mass spectrometry. Results Complete data were obtained from 5 patients. Serum levels of PA decreased significantly during the study period (0.137 ± 0.078 mg/L vs 0.124 ± 0.049 mg/L, p = 0.04), and the respective levels of DEHP decreased insignificantly (0.097 ± 0.076 mg/L vs 0.069 ± 0.046 mg/L, p = 0.07), whereas the concentrations of MEHP and 2-EH remained unchanged. Urine concentrations of PA were high (0.81 ± 0.69 mg/L) but did not change substantially (0.70 ± 0.50 mg/L). Effluent dialysate concentrations of MEHP and PA decreased significantly (0.0176 ± 0.004 mg/L vs 0.0040 ± 0.0007 mg/L, p = 0.043 and 0.158 ± 0.056 mg/L vs 0.111 ± 0.051 mg/L, p = 0.043, respectively). Conclusions Although PD patients seem to be exposed to other sources of phthalates in addition to dialysis, use of plasticizer-free devices may help to reduce potentially immunosuppressive exposure to phthalate esters.
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Affiliation(s)
- Thomas Mettang
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart
| | | | - Dominik Mark Alscher
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart
| | | | - Roman Wodarz
- Department of Occupational and Social Medicine, University of Tuebingen, Tuebingen
| | - Albert W. Rettenmeier
- Department of Hygiene and Occupational Medicine, University of Essen, Essen, Germany
| | - Ulrich Kuhlmann
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart
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Mettang T, Fischer FP, Dunst R, Kuhlmann U, Rettenmeier AW. Plasticizers in Renal Failure: Aspects of Metabolism and Toxicity. Perit Dial Int 2020. [DOI: 10.1177/089686089701702s06] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Thomas Mettang
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart
| | - Frank-Peter Fischer
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart
| | - Robert Dunst
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart
| | - Ulrich Kuhlmann
- Division of Nephrology, Department of Internal Medicine, Robert Bosch Hospital, Stuttgart
| | - Albert W. Rettenmeier
- Department of Hygiene and Occupational Medicine, University of Essen, Essen, Germany
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Bai J, He Z, Li Y, Jiang X, Yu H, Tan Q. Mono-2-ethylhexyl phthalate induces the expression of genes involved in fatty acid synthesis in HepG2 cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2019; 69:104-111. [PMID: 31004931 DOI: 10.1016/j.etap.2019.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 03/28/2019] [Accepted: 04/08/2019] [Indexed: 06/09/2023]
Abstract
Mono-2-ethylhexyl phthalate (MEHP) is a major bioactive metabolite in the widely used industrial plasticizer diethylhexyl phthalate (DEHP) that has been found to be toxic to the liver. The aim of this study is to determine whether MEHP exposure can change the expression of fatty acid metabolism-related genes in HepG2 cells, which might be related to non-alcoholic fatty liver disease (NAFLD). The results revealed that exposure to MEHP promoted lipid accumulation in HepG2 cells. The levels of intracellular triglycerides in the hepatocytes increased after exposure to 0.8-100 μM MEHP for 24 h and 48 h. The genetic expressions of SREBP-1c, ChREBP, ACC1, FASN, and SCD significantly increased at 6 h after exposure to MEHP. At 24 h, the expression of the SREBP-1c and ChREBP genes remained increased, while the expression of the FASN and SCD genes decreased. At 48 h, the expression of SREBP-1c, ChREBP, ACC1, FASN, and SCD decreased. Furthermore, the levels of proteins including ACC1, FASN, SCD, and ChREBP (except SREBP-1c) increased at 24 h. These findings suggest that MEHP exposure can promote fatty acid synthesis in hepatocytes by regulating the expression of relevant genes and proteins, contributing to NAFLD.
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Affiliation(s)
- Jianying Bai
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China.
| | - Zhen He
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Yaofu Li
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Xuexia Jiang
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Hongmei Yu
- Department of Health Statistics, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Qing Tan
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
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15
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de la Rosa Rodriguez MA, Sugahara G, Hooiveld GJEJ, Ishida Y, Tateno C, Kersten S. The whole transcriptome effects of the PPARα agonist fenofibrate on livers of hepatocyte humanized mice. BMC Genomics 2018; 19:443. [PMID: 29879903 PMCID: PMC5991453 DOI: 10.1186/s12864-018-4834-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/29/2018] [Indexed: 01/08/2023] Open
Abstract
Background The role of PPARα in gene regulation in mouse liver is well characterized. However, less is known about the role of PPARα in human liver. The aim of the present study was to better characterize the impact of PPARα activation on gene regulation in human liver. To that end, chimeric mice containing hepatocyte humanized livers were given an oral dose of 300 mg/kg fenofibrate daily for 4 days. Livers were collected and analyzed by hematoxilin and eosin staining, qPCR, and transcriptomics. Transcriptomics data were compared with existing datasets on PPARα activation in normal mouse liver, human primary hepatocytes, and human precision cut liver slices. Results Of the different human liver models, the gene expression profile of hepatocyte humanized livers most closely resembled actual human liver. In the hepatocyte humanized mouse livers, the human hepatocytes exhibited excessive lipid accumulation. Fenofibrate increased the size of the mouse but not human hepatocytes, and tended to reduce steatosis in the human hepatocytes. Quantitative PCR indicated that induction of PPARα targets by fenofibrate was less pronounced in the human hepatocytes than in the residual mouse hepatocytes. Transcriptomics analysis indicated that, after filtering, a total of 282 genes was significantly different between fenofibrate- and control-treated mice (P < 0.01). 123 genes were significantly lower and 159 genes significantly higher in the fenofibrate-treated mice, including many established PPARα targets such as FABP1, HADHB, HADHA, VNN1, PLIN2, ACADVL and HMGCS2. According to gene set enrichment analysis, fenofibrate upregulated interferon/cytokine signaling-related pathways in hepatocyte humanized liver, but downregulated these pathways in normal mouse liver. Also, fenofibrate downregulated pathways related to DNA synthesis in hepatocyte humanized liver but not in normal mouse liver. Conclusion The results support the major role of PPARα in regulating hepatic lipid metabolism, and underscore the more modest effect of PPARα activation on gene regulation in human liver compared to mouse liver. The data suggest that PPARα may have a suppressive effect on DNA synthesis in human liver, and a stimulatory effect on interferon/cytokine signalling.
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Affiliation(s)
- Montserrat A de la Rosa Rodriguez
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708, WE, Wageningen, The Netherlands
| | - Go Sugahara
- Research and Development Department, PhoenixBio, Co., Ltd, 3-4-1 Kagamiyama, Higashi-, Hiroshima, Japan
| | - Guido J E J Hooiveld
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708, WE, Wageningen, The Netherlands
| | - Yuji Ishida
- Research and Development Department, PhoenixBio, Co., Ltd, 3-4-1 Kagamiyama, Higashi-, Hiroshima, Japan.,Liver Research Project Center, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Chise Tateno
- Research and Development Department, PhoenixBio, Co., Ltd, 3-4-1 Kagamiyama, Higashi-, Hiroshima, Japan.,Liver Research Project Center, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Sander Kersten
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708, WE, Wageningen, The Netherlands.
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Walker CL, Pomatto LCD, Tripathi DN, Davies KJA. Redox Regulation of Homeostasis and Proteostasis in Peroxisomes. Physiol Rev 2017; 98:89-115. [PMID: 29167332 DOI: 10.1152/physrev.00033.2016] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 06/19/2017] [Accepted: 06/21/2017] [Indexed: 02/08/2023] Open
Abstract
Peroxisomes are highly dynamic intracellular organelles involved in a variety of metabolic functions essential for the metabolism of long-chain fatty acids, d-amino acids, and many polyamines. A byproduct of peroxisomal metabolism is the generation, and subsequent detoxification, of reactive oxygen and nitrogen species, particularly hydrogen peroxide (H2O2). Because of its relatively low reactivity (as a mild oxidant), H2O2 has a comparatively long intracellular half-life and a high diffusion rate, all of which makes H2O2 an efficient signaling molecule. Peroxisomes also have intricate connections to mitochondria, and both organelles appear to play important roles in regulating redox signaling pathways. Peroxisomal proteins are also subject to oxidative modification and inactivation by the reactive oxygen and nitrogen species they generate, but the peroxisomal LonP2 protease can selectively remove such oxidatively damaged proteins, thus prolonging the useful lifespan of the organelle. Peroxisomal homeostasis must adapt to the metabolic state of the cell, by a combination of peroxisome proliferation, the removal of excess or badly damaged organelles by autophagy (pexophagy), as well as by processes of peroxisome inheritance and motility. More recently the tumor suppressors ataxia telangiectasia mutate (ATM) and tuberous sclerosis complex (TSC), which regulate mTORC1 signaling, have been found to regulate pexophagy in response to variable levels of certain reactive oxygen and nitrogen species. It is now clear that any significant loss of peroxisome homeostasis can have devastating physiological consequences. Peroxisome dysregulation has been implicated in several metabolic diseases, and increasing evidence highlights the important role of diminished peroxisomal functions in aging processes.
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Affiliation(s)
- Cheryl L Walker
- Center for Precision Environmental Health and Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas; and Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, California
| | - Laura C D Pomatto
- Center for Precision Environmental Health and Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas; and Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, California
| | - Durga Nand Tripathi
- Center for Precision Environmental Health and Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas; and Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, California
| | - Kelvin J A Davies
- Center for Precision Environmental Health and Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas; and Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, California
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17
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Topaktas M, Kafkas NE, Sadighazadi S, Istifli ES. In vitro cytogenetic toxicity of bezafibrate in human peripheral blood lymphocytes. Cytotechnology 2017; 69:579-589. [PMID: 28097454 PMCID: PMC5507839 DOI: 10.1007/s10616-017-0069-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/11/2017] [Indexed: 01/14/2023] Open
Abstract
Bezafibrate (BF) is a peroxisome proliferator-activated receptor (PPAR) agonist used as a lipid-lowering agent to treat both the familial or acquired combined forms of hyperlipidemia. BF is the only available fibrate drug that acts on all PPAR subtypes of α, β, and δ. Although there are studies that indicate a genotoxic potential associated with the use of fibrates, to our knowledge, the genotoxicity of BF in human peripheral blood lymphocytes has not been studied. In the present study, the genotoxic potential of BF was evaluated using chromosome aberration (CA) and micronucleus (MN) assays in peripheral blood lymphocytes of healthy human subjects. In addition, a high performance liquid chromatography (HPLC) method was used to identify and quantitate the drug passage into the cells. Human peripheral blood lymphocytes were exposed to four different concentrations (100, 175, 250 and 325 μg/mL) of BF for 24- and 48-h treatment periods. As shown by HPLC, in spite of significant passage of BF into human peripheral blood lymphocytes in 24- and 48-h treatment periods, BF was not found to increase the CA and MN frequency. On the other hand, exposing cells to BF for 24- and 48-h treatment periods caused significant concentration-dependent decreases in the mitotic index (r = -0.995, p < 0.01 for 24-h; r = -0.992, p < 0.01 for 48-h) and nuclear division index (r = -0.990, p < 0.01 for 24-h; r = -0.981, p < 0.01 for 48-h). Our results suggest that BF has cytotoxic effect on cultured human peripheral blood lymphocytes.
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Affiliation(s)
- M Topaktas
- Department of Biology, Faculty of Science and Letters, Cukurova University, 01330, Adana, Turkey
| | - N E Kafkas
- Department of Horticulture, Faculty of Agriculture, Cukurova University, 01330, Adana, Turkey
| | - S Sadighazadi
- Department of Biology, Institute of Basic and Applied Sciences, Cukurova University, 01330, Adana, Turkey
| | - E S Istifli
- Department of Biology, Faculty of Science and Letters, Cukurova University, 01330, Adana, Turkey.
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18
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Tanaka N, Aoyama T, Kimura S, Gonzalez FJ. Targeting nuclear receptors for the treatment of fatty liver disease. Pharmacol Ther 2017; 179:142-157. [PMID: 28546081 DOI: 10.1016/j.pharmthera.2017.05.011] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ligand-activated nuclear receptors, including peroxisome proliferator-activated receptor alpha (PPARα), pregnane X receptor, and constitutive androstane receptor, were first identified as key regulators of the responses against chemical toxicants. However, numerous studies using mouse disease models and human samples have revealed critical roles for these receptors and others, such as PPARβ/δ, PPARγ, farnesoid X receptor (FXR), and liver X receptor (LXR), in maintaining nutrient/energy homeostasis in part through modulation of the gut-liver-adipose axis. Recently, disorders associated with disrupted nutrient/energy homeostasis, e.g., obesity, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD), are increasing worldwide. Notably, in NAFLD, a progressive subtype exists, designated as non-alcoholic steatohepatitis (NASH) that is characterized by typical histological features resembling alcoholic steatohepatitis (ASH), and NASH/ASH are recognized as major causes of hepatitis virus-unrelated liver cirrhosis and hepatocellular carcinoma. Since hepatic steatosis is basically caused by an imbalance between fat/energy influx and utilization, abnormal signaling of these nuclear receptors contribute to the pathogenesis of fatty liver disease. Standard therapeutic interventions have not been fully established for fatty liver disease, but some new agents that activate or inhibit nuclear receptor signaling have shown promise as possible therapeutic targets. In this review, we summarize recent findings on the roles of nuclear receptors in fatty liver disease and discuss future perspectives to develop promising pharmacological strategies targeting nuclear receptors for NAFLD/NASH.
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Affiliation(s)
- Naoki Tanaka
- Department of Metabolic Regulation, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan.
| | - Toshifumi Aoyama
- Department of Metabolic Regulation, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan
| | - Shioko Kimura
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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Madureira TV, Pinheiro I, de Paula Freire R, Rocha E, Castro LF, Urbatzka R. Genome specific PPARαB duplicates in salmonids and insights into estrogenic regulation in brown trout. Comp Biochem Physiol B Biochem Mol Biol 2017; 208-209:94-101. [PMID: 28414176 DOI: 10.1016/j.cbpb.2017.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/10/2017] [Accepted: 04/10/2017] [Indexed: 02/04/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are key regulators of many processes in vertebrates, such as carbohydrate and lipid metabolism. PPARα, a member of the PPAR nuclear receptor gene subfamily (NR1C1), is involved in fatty acid metabolism, namely in peroxisomal β-oxidation. Two gene paralogues, pparαA and pparαB, were described in several teleost species with their origin dating back to the teleost-specific genome duplication (3R). Given the additional salmonid-specific genome duplication (4R), four genes could be theoretically anticipated for this gene subfamily. In this work, we examined the pparα gene repertoire in brown trout, Salmo trutta f. fario. Data disclosed two pparα-like sequences in brown trout. Phylogenetic analyses further revealed that the isolated genes are most likely genome pparαB duplicates, pparαBa and pparαBb, while pparαA is apparently absent in salmonids. Both genes showed a ubiquitous mRNA expression across a panel of 11 different organs. In vitro exposed primary brown trout hepatocytes strongly suggest that pparα gene paralogues are differently regulated by ethinylestradiol (EE2). PparαBb mRNA expression significantly decreased with dosage, reaching significance after exposure to 50μM EE2, while pparαBa mRNA increased, significant at 1μM EE2. The present data enhances the understanding of pparα function and evolution in teleost, and reinforces the evidence of a potential crosstalk between estrogenic and pparα signaling pathways.
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Affiliation(s)
- Tânia Vieira Madureira
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; ICBAS - Institute of Biomedical Sciences Abel Salazar, Department of Microscopy, Laboratory Histology and Embryology, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Ivone Pinheiro
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; ICBAS - Institute of Biomedical Sciences Abel Salazar, Department of Microscopy, Laboratory Histology and Embryology, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Rafaelle de Paula Freire
- ICBAS - Institute of Biomedical Sciences Abel Salazar, Department of Microscopy, Laboratory Histology and Embryology, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Eduardo Rocha
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; ICBAS - Institute of Biomedical Sciences Abel Salazar, Department of Microscopy, Laboratory Histology and Embryology, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Luis Filipe Castro
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; FCUP - Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Ralph Urbatzka
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal.
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Peroxisome Proliferator-Activated Receptor α Activation Is Not the Main Contributor to Teratogenesis Elicited by Polar Compounds from Oxidized Frying Oil. Int J Mol Sci 2017; 18:ijms18030510. [PMID: 28264465 PMCID: PMC5372526 DOI: 10.3390/ijms18030510] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/16/2017] [Accepted: 02/23/2017] [Indexed: 01/28/2023] Open
Abstract
We previously reported that polar compounds (PO) in cooking oil are teratogenic and perturbed retinoic acid (RA) metabolism. Considering PO as a potent peroxisome proliferator-activated receptor α (PPARα) activator, this study aimed to investigate the role of PPARα in PO-induced teratogenesis and disturbance of RA metabolism. Female PPARα knockout or wild type mice were mated with males of the same genotype. Pregnant mice were fed a diet containing 10% fat from either fresh oil (FO) or PO from gestational day1 to day18, and killed at day18. The PO diet significantly increased the incidence of teratogenesis and fetal RA concentrations, regardless of genotype. Though PPARα deficiency disturbed maternal RA homeostasis, itself did not contribute to teratogenesis as long as FO diet was given. The mRNA profile of genes involved in RA metabolism was differentially affected by diet or genotype in mothers and fetuses. Based on hepatic mRNA levels of genes involved in xenobiotic metabolism, we inferred that PO not only activated PPARα, but also altered transactivity of other xenobiotic receptors. We concluded that PO-induced fetal anomalies and RA accumulation were independent of PPARα activation.
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22
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Turnbull D, Rodricks JV. Assessment of Possible Carcinogenic Risk to Humans Resulting from Exposure to Di(2-ethylhexyl)phthalate (DEHP). ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915818509014509] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The purpose of this work was to estimate the degree of risk that might be associated with human exposure to low levels of the plasticizer di(2-ethylhexyl)phthalate (DEHP). DEHP is a common component, sometimes at high concentrations, of polyvinyl chloride (PVC) plastics and was recently reported by the National Toxicology Program (NTP) to be carcinogenic in rats and mice, inducing hepatocellular tumors in both species. This work was also designed to illustrate an approach to risk assessment that attempts to incorporate all available biological data. Based on the dose-response data generated by the NTP bioassays, we have performed extrapolations of risk to low dose levels using several procedures, including some that incorporate inferences from the available data that shed light on the likely relationship between dose level and risk at low dose levels. In drawing these inferences, consideration was given to such factors as genotoxicity, metabolism and pharmacokinetics, and physiological and biochemical effects of DEHP that might reveal its mechanism of action. The relative merits of each of the various risk estimates are described, based on current understanding of DEHP's mode of biological action. It is concluded that DEHP's mechanism of carcinogenicity in rodents most likely involves its ability to induce peroxisome proliferation and related enzymatic changes, although other mechanisms cannot be excluded. If humans and rodents are assumed to be at the same risk at the same daily dose level of DEHP, application of the various low dose extrapolation models leads to the prediction that the daily dose resulting in a lifetime risk of no more than 1 in 1 million would be between 1.5 and 791 mg/kg per day, with the most likely figure being 116 mg/kg per day. If the carcinogenicity of DEHP is dependent upon its pattern of metabolism, however, it would be inappropriate to extrapolate from rodents to man without qualification because of the major quantitative differences in metabolism in rats, mice, and primates, including man. One of the major differences in metabolism of DEHP between rats and mice and primates is in production of a metabolite whose level may be an indicator of the level of peroxisomal activity and, hence, if the peroxisome proliferation theory of DEHP carcinogenicity is correct, of carcinogenic risk. However, the substantial doubt that exists regarding the applicability of rodent carcinogenicity data to humans must be expressed in qualitative terms.
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Affiliation(s)
- D. Turnbull
- Duncan Turnbull Environ Corporation 1000 Potomac Street, N.W. Washington, DC 20007
| | - J. V. Rodricks
- Duncan Turnbull Environ Corporation 1000 Potomac Street, N.W. Washington, DC 20007
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Munro IC, Carlo GL, Orr JC, Sund KG, Wilson RM, Kennepohl E, Lynch BS, Jablinske M. A Comprehensive, Integrated Review and Evaluation of the Scientific Evidence Relating to the Safety of the Herbicide 2,4-D. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915819209141893] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The safety of 2,4-D to farm and forestry workers, commercial applicators and the general public has been of continuing concern because certain epidemiological studies of groups potentially exposed to 2,4-D have suggested a relationship between 2,4-D use and increased risk of soft tissue sarcoma, Hodgkin's disease or non-Hodgkin's lymphoma. This review on 2,4-D is unique in that the approach taken was to integrate data from worker exposure studies, whole animals, metabolic and other relevant laboratory studies with the epidemiological findings to assess the extent to which there is scientific support for the hypothesis that 2,4-D exposure is associated with any increased risk of human cancer. The case-control epidemiological studies that have been the source of the cancer risk hypothesis are inconclusive. Problems in assessing exposure based on patients' memories make these studies difficult to interpret. Cohort studies of exposed workers do not generally support the specific hypothesis that 2,4-D causes cancer. Taken together, the epidemiological studies provide, at best, only weak evidence of an association between 2,4-D and the risk of cancer. Importantly, the cancer hypothesis is not supported by other data. A critical evaluation of the exposure data indicates that exposure to 2,4-D in user groups is intermittent and much lower than the doses tested chronically in long-term animal studies that have not shown evidence of tumor induction. Moreover, the structure of 2,4-D does not suggest it would be a carcinogen. 2,4-D is a simple organic acid, that is largely excreted unchanged, and there is no evidence that it is metabolized to critically reactive metabolites or accumulates in tissues. This evidence is supported by a large body of negative studies on genotoxicity, which taken together with the metabolic studies, clearly indicates that 2,4-D is highly unlikely to be a genotoxic carcinogen. Furthermore, 2,4-D has no known hormonal activity and does not induce proliferative changes in any tissue or organ, indicating that it does not possess any of the characteristics of non-genotoxic animal carcinogens. Thus the available mechanistic studies provide no plausible basis for a hypothesis of carcinogenicity. In this review, data relating to potential neurotoxicity, immunotoxicity and reproductive toxicity also were evaluated. There is no evidence that 2,4-D adversely affects the immune system and neurotoxic and reproductive effects only have been associated with high toxic doses that would not be encountered by 2,4-D users. Historical exposures to 2,4-D by user groups, particularly farmers, forestry workers and commercial applicators, would be higher than those sustained under present rigorous standards for application which involve the use of protective clothing and other measures to reduce exposure. Proposed label changes indicate that in the future exposures will be even further reduced. Viewed in this context, the available data indicate that the potential public health impact of 2,4-D, including the risk of human cancer, was negligible in the past and would be expected to be even smaller in the present and future.
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Affiliation(s)
- Ian C. Munro
- CanTox Inc., 2233 Argentia Road, Suite 308, Mississauga, Ontario, Canada L5N 2X7
| | - George L. Carlo
- Health & Environmental Sciences Group Ltd., 1513 Sixteenth Street NW, Washington, DC 20036
| | - Joan C. Orr
- CanTox Inc., 2233 Argentia Road, Suite 308, Mississauga, Ontario, Canada L5N 2X7
| | - Kelly G. Sund
- Health & Environmental Sciences Group Ltd., 1513 Sixteenth Street NW, Washington, DC 20036
| | - Ross M. Wilson
- CanTox Inc., 2233 Argentia Road, Suite 308, Mississauga, Ontario, Canada L5N 2X7
| | - Elke Kennepohl
- CanTox Inc., 2233 Argentia Road, Suite 308, Mississauga, Ontario, Canada L5N 2X7
| | - Barry S. Lynch
- CanTox Inc., 2233 Argentia Road, Suite 308, Mississauga, Ontario, Canada L5N 2X7
| | - Maureen Jablinske
- Health & Environmental Sciences Group Ltd., 1513 Sixteenth Street NW, Washington, DC 20036
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De La Iglesia FA, Gray RH, Mcguire EJ. Subcellular Organelle Biogenesis and Dynamics in Peroxisome Proliferation. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915819209141873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Peroxisome proliferation, a phenomenon studied intensively for the past quarter century is a seemingly uniform reaction of the liver to hypolipidemic drugs and some industrial chemicals. However, application of quantitative microscopic techniques revealed unsuspected characteristics, and facilitated the analysis of peroxisome biogenesis, a dynamic process occurring without disruption of the hepatocyte architecture. The rate of peroxisome biogenesis accelerates to a significant degree within a brief period after compound administration, and the peroxisome population can accumulate up to seven times the normal level. Degradation of peroxisomes follows a triphasic curve and the overall rate of elimination is about the same as the rate of accumulation. Quantitative morphometric studies show interspecies differences in peroxisome induction, with rats being the most susceptible species. Hamsters show peroxisome induction although not to the same substantive extent seen in rats. Monkeys and dogs show poor response, but longer-term data are needed.
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Affiliation(s)
- Felix A. De La Iglesia
- Department of Pathology and Experimental Toxicology Parke-Davis Pharmaceutical Research Division Warner-Lambert Company Ann Arbor, MI
| | - Robert H. Gray
- Department of Pathology and Experimental Toxicology Parke-Davis Pharmaceutical Research Division Warner-Lambert Company Ann Arbor, MI
| | - Edward J. Mcguire
- Department of Pathology and Experimental Toxicology Parke-Davis Pharmaceutical Research Division Warner-Lambert Company Ann Arbor, MI
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Mcguire EJ, Gray RH, De La Iglesia FA. Chemical Structure-Activity Relationships: Peroxisome Proliferation and Lipid Regulation in Rats. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915819209141875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Studies described here address structure-activity relationships of novel hypolipidemic agents that induce peroxisome proliferation. Male rats were given equivalent doses of three well-studied fibrates, fibrate amides, and structurally dissimilar agents. Aryloxyalkanoic acids, amide analogs, and thio, benzimidazole, phenylpiperazine, and oxazole derivatives induced peroxisome proliferation and decreased plasma cholesterol and triglyceride levels. These compounds contain an acidic function or appear to be readily metabolized to a derivative with an acidic function. Substitution of this substituent with an adamantyloxy eliminated peroxisome proliferation and induced contrasting effects on the lipid profile, substantially increasing triglycerides. A direct correlation was established between hepatocellular peroxisome proliferation and plasma high-density lipoprotein (HDD-cholesterol levels.
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Affiliation(s)
- Edward J. Mcguire
- Department of Pathology and Experimental Toxicology Parke-Davis Pharmaceutical Research Division Warner-Lambert Company Ann Arbor, MI
| | - Robert H. Gray
- Department of Pathology and Experimental Toxicology Parke-Davis Pharmaceutical Research Division Warner-Lambert Company Ann Arbor, MI
| | - Felix A. De La Iglesia
- Department of Pathology and Experimental Toxicology Parke-Davis Pharmaceutical Research Division Warner-Lambert Company Ann Arbor, MI
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26
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Di Meo S, Reed TT, Venditti P, Victor VM. Role of ROS and RNS Sources in Physiological and Pathological Conditions. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:1245049. [PMID: 27478531 PMCID: PMC4960346 DOI: 10.1155/2016/1245049] [Citation(s) in RCA: 744] [Impact Index Per Article: 93.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 05/04/2016] [Accepted: 05/23/2016] [Indexed: 12/19/2022]
Abstract
There is significant evidence that, in living systems, free radicals and other reactive oxygen and nitrogen species play a double role, because they can cause oxidative damage and tissue dysfunction and serve as molecular signals activating stress responses that are beneficial to the organism. Mitochondria have been thought to both play a major role in tissue oxidative damage and dysfunction and provide protection against excessive tissue dysfunction through several mechanisms, including stimulation of opening of permeability transition pores. Until recently, the functional significance of ROS sources different from mitochondria has received lesser attention. However, the most recent data, besides confirming the mitochondrial role in tissue oxidative stress and protection, show interplay between mitochondria and other ROS cellular sources, so that activation of one can lead to activation of other sources. Thus, it is currently accepted that in various conditions all cellular sources of ROS provide significant contribution to processes that oxidatively damage tissues and assure their survival, through mechanisms such as autophagy and apoptosis.
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Affiliation(s)
- Sergio Di Meo
- Dipartimento di Biologia, Università di Napoli “Federico II”, 80126 Napoli, Italy
| | - Tanea T. Reed
- Department of Chemistry, Eastern Kentucky University, Richmond, KY 40475, USA
| | - Paola Venditti
- Dipartimento di Biologia, Università di Napoli “Federico II”, 80126 Napoli, Italy
| | - Victor Manuel Victor
- Service of Endocrinology, University Hospital Dr. Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46010 Valencia, Spain
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27
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Ochs JB, Baldwin LA, Leonard DA, Calabrese EJ. Effects of Joint Exposures to Selected Peroxisome Proliferators on Hepatic Acyl-CoA Oxidase Activity in Male B6C3F1 Mice. Hum Exp Toxicol 2016; 11:83-8. [PMID: 1349224 DOI: 10.1177/096032719201100204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The interaction potential of peroxisome proliferators of similar and dissimilar structure was examined in B6C3F1 mice. Mice were fed diets containing varying concentrations of ciprofibrate (Cipro), clofibrate (Clof) or di(2-ethylhexyl)phthalate (DEHP), or combinations of Cipro and Clof or Cipro and DEHP for 4 d. Induction of peroxisomal beta-oxidation, measured by increased acyl-CoA oxidase activity, was used as the endpoint for analysis. An additive response occurred following joint exposure to the structurally related compounds Cipro and Clof, whereas a possible synergistic response occurred at low dose combinations of the structurally dissimilar Cipro and DEHP. These findings represent the first report assessing the in-vivo interaction potential of structurally similar and dissimilar peroxisome proliferators and provides insight into the dose-response nature of joint exposures to certain non-genotoxic carcinogens.
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Affiliation(s)
- J B Ochs
- Environmental Health Sciences Program, School of Public Health, University of Massachusetts, Amherst 01003
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28
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29
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Maternal exposure to di-(2-ethylhexyl) phthalate exposure deregulates blood pressure, adiposity, cholesterol metabolism and social interaction in mouse offspring. Arch Toxicol 2015; 90:1211-24. [DOI: 10.1007/s00204-015-1539-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/13/2015] [Indexed: 01/28/2023]
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30
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Wang J, Betancourt A, Jenkins S, Biro F, Pinney SM, Chen D, Russo J, Lamartiniere CA. Altered blood proteome in girls with high urine concentrations of bisphenol a, genistein, mono-ethyl hexylphthalate and mono-benzyl phthalate. ACTA ACUST UNITED AC 2015; 2:44-57. [PMID: 31360934 DOI: 10.15406/mojpb.2015.02.00040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Children exposed to endocrine disruptors are hypothesized to be susceptible for cancer development later in life. Identifying functional biomarkers of specific exposures may indicate predisposition for this disease. The objectives of this study were to identify protein biomarkers of 1) effect and 2) susceptibility for cancer from the blood of girls exposed to select environmental chemicals. In prepubertal girls, urine concentrations of bisphenol A (BPA), genistein, mono-ethyl hexylphthalate (MEHP) and mono-benzyl phthalate (MBzP) were used to identify girls in the top quintile of exposure for each of these environmental chemicals, and age-matched prepubertal girls with urine analyte concentrations below the median. Blood samples of these girls were depleted of the seven most abundant proteins using human-specific affinity spin columns. Using isobaric Tandem Mass Tags and quantitative mass spectrometry (TMT-MS), 51, 34, 57 and 47 differentially expressed proteins were identified from the blood of prepubertal girls with high urine concentrations of BPA, genistein, MEHP and MBzP, respectively, compared to controls. The data demonstrates the potential of proteomic technology to not only provide biomarkers of effect from aminimally invasive source of biological material, blood, but to identify protein molecules that are intimately involved in the pathobiology of cancer. The differentially regulated cancer associated proteins in girls with high concentrations of BPA and genistein are consistent with reported roles of BPA in carcinogenesis and of genistein in mammary cancer prevention, respectively.
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Affiliation(s)
- Jun Wang
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, USA
| | - Angela Betancourt
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, USA
| | - Sarah Jenkins
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, USA
| | - Frank Biro
- Division of Adolescent Medicine, Children's Hospital Medical Center, USA
| | - Susan M Pinney
- Department of Environmental Health, University of Cincinnati College of Medicine, USA
| | - Dongquan Chen
- Division of Preventive Medicine, UAB.,UAB Comprehensive Cancer Center, University of Alabama at Birmingham, USA
| | - Jose Russo
- The Irma Russo Breast Cancer Research Laboratory, Fox Chase Cancer Center-Temple University Health System, USA
| | - Coral A Lamartiniere
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, USA.,UAB Comprehensive Cancer Center, University of Alabama at Birmingham, USA
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31
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Zhao JF, Hsiao SH, Hsu MH, Pao KC, Kou YR, Shyue SK, Lee TS. Di-(2-ethylhexyl) phthalate accelerates atherosclerosis in apolipoprotein E-deficient mice. Arch Toxicol 2014; 90:181-90. [DOI: 10.1007/s00204-014-1377-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 09/19/2014] [Indexed: 12/31/2022]
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32
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Effects of clofibric acid alone and in combination with 17β-estradiol on mRNA abundance in primary hepatocytes isolated from rainbow trout. Toxicol In Vitro 2014; 28:1106-16. [DOI: 10.1016/j.tiv.2014.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 05/11/2014] [Accepted: 05/14/2014] [Indexed: 12/08/2022]
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33
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Misra P, Reddy JK. Peroxisome proliferator-activated receptor-α activation and excess energy burning in hepatocarcinogenesis. Biochimie 2014; 98:63-74. [DOI: 10.1016/j.biochi.2013.11.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 11/14/2013] [Indexed: 01/23/2023]
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34
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Yavaşoğlu NÜK, Köksal C, Dağdeviren M, Aktuğ H, Yavaşoğlu A. Induction of oxidative stress and histological changes in liver by subacute doses of butyl cyclohexyl phthalate. ENVIRONMENTAL TOXICOLOGY 2014; 29:345-353. [PMID: 22936646 DOI: 10.1002/tox.21813] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 08/02/2012] [Accepted: 08/04/2012] [Indexed: 06/01/2023]
Abstract
Phthalates are esters of phthalic acid and are mainly used as plasticizers in a wide variety of products and applications. There is no information on butyl cyclohexyl phthalate (BCP) toxicity. This study was performed to evaluate the histopathological effects and to determine oxidative stress inducing potential in liver by subacute exposure of BCP. The animals of the treatment groups were orally administered 100, 200, and 400 mg/kg/day BCP for 5 consecutive days per week during 28 days. As a result, no significant changes were observed in body weight gains, and absolute and relative liver weights of liver of BCP treated mice, when compared with control group. Although the degree of lipid peroxidation in the liver tissue of all BCP exposure groups were significantly higher than those of the control (p < 0.01), SOD and CAT activities in liver tissue of mice of 200 and 400 mg/kg exposure groups were significantly lower than those of the controls (p < 0.01). Moreover, BCP caused dose-dependent histological changes in the liver of mice such as congestions in vena centralis, an enlargement of the sinusoids, degeneration in hepatocytes, vacuole formations and presence of lipid droplets in hepatocytes, eosinophilic cytoplasm. While iNOS immunoreactivity was increased in all treatment groups, Type IV collagen and Connexin 43 immunoreactivities were decreased in all treatment groups compared with the control group. Significant decrease was observed in the number of TUNEL-positive liver cells of BCP treated mice. These results suggested that BCP exposure induces oxidative stress in liver and exposure of BCP during long time period could lead to hepatocarcinogenesis.
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35
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Holovska K, Almasiova V, Cigankova V. Ultrastructural changes in the rabbit liver induced by carbamate insecticide bendiocarb. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2014; 49:616-623. [PMID: 24901965 DOI: 10.1080/03601234.2014.911593] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Carbamates (CB) are used as insecticides and some of them have been registered as human drugs. The mechanism of CB poisoning involves reversible inhibition of acetylcholine esterase. In the present study, we investigated changes in liver ultrastructure in rabbits (Oryctolagus cuniculus) which were administered bendiocarb for 3, 10, 20, and 30 days. Rabbits in all experimental groups received capsules of bendiocarb (96% Bendiocarb, Bayer, Germany) per os daily at a dose of 5 mg/kg of body weight, and after day 11 received the same dose every 48 h. The observed changes were only moderate, focal, and the effect on the liver was not uniform. On the third day of the experiment, injured hepatocytes had dilated bile capillaries with reduced microvilli. There were no visible alterations in the intercellular contacts. Nuclei of these cells were irregular in shape. Many hepatocytes showed considerable increase in the number of peroxisomes. On day 10 of the experiment, the number of peroxisomes was reduced. Other changes, such as dilated rough endoplasmic reticulum and proliferation of smooth endoplasmic reticulum were observed on day 20. The number of lipid droplets in hepatocytes gradually increased. Usually they were present in low numbers, but on day 30 of the experiment their number increased significantly. They coalesced and formed a single lipid droplet which changed the shape of the nuclei. The results presented in this study indicate that both short and long-term administration of bendiocarb affects the liver ultrastructure. At the same time we also observed rapid onset of regeneration of the damaged tissue through activation of hepatocytes and oval cells.
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Affiliation(s)
- Katarina Holovska
- a Department of Anatomy, Histology and Physiology , University of Veterinary Medicine and Pharmacy , Kosice , Slovak Republic
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36
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Jia Y, Viswakarma N, Reddy JK. Med1 subunit of the mediator complex in nuclear receptor-regulated energy metabolism, liver regeneration, and hepatocarcinogenesis. Gene Expr 2014; 16:63-75. [PMID: 24801167 PMCID: PMC4093800 DOI: 10.3727/105221614x13919976902219] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Several nuclear receptors regulate diverse metabolic functions that impact on critical biological processes, such as development, differentiation, cellular regeneration, and neoplastic conversion. In the liver, some members of the nuclear receptor family, such as peroxisome proliferator-activated receptors (PPARs), constitutive androstane receptor (CAR), farnesoid X receptor (FXR), liver X receptor (LXR), pregnane X receptor (PXR), glucocorticoid receptor (GR), and others, regulate energy homeostasis, the formation and excretion of bile acids, and detoxification of xenobiotics. Excess energy burning resulting from increases in fatty acid oxidation systems in liver generates reactive oxygen species, and the resulting oxidative damage influences liver regeneration and liver tumor development. These nuclear receptors are important sensors of exogenous activators as well as receptor-specific endogenous ligands. In this regard, gene knockout mouse models revealed that some lipid-metabolizing enzymes generate PPARα-activating ligands, while others such as ACOX1 (fatty acyl-CoA oxidase1) inactivate these endogenous PPARα activators. In the absence of ACOX1, the unmetabolized ACOX1 substrates cause sustained activation of PPARα, and the resulting increase in energy burning leads to hepatocarcinogenesis. Ligand-activated nuclear receptors recruit the multisubunit Mediator complex for RNA polymerase II-dependent gene transcription. Evidence indicates that the Med1 subunit of the Mediator is essential for PPARα, PPARγ, CAR, and GR signaling in liver. Med1 null hepatocytes fail to respond to PPARα activators in that these cells do not show induction of peroxisome proliferation and increases in fatty acid oxidation enzymes. Med1-deficient hepatocytes show no increase in cell proliferation and do not give rise to liver tumors. Identification of nuclear receptor-specific coactivators and Mediator subunits should further our understanding of the complexities of metabolic diseases associated with increased energy combustion in liver.
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Affiliation(s)
- Yuzhi Jia
- *Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Navin Viswakarma
- †Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Maywood, IL, USA
| | - Janardan K. Reddy
- *Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
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37
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Differential induction of cytochrome P450 isoforms and peroxisomal proliferation by cyfluthrin in male Wistar rats. Toxicol Lett 2013; 220:135-42. [DOI: 10.1016/j.toxlet.2013.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 04/16/2013] [Accepted: 04/18/2013] [Indexed: 11/19/2022]
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38
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Hepatic and renal Bcrp transporter expression in mice treated with perfluorooctanoic acid. Toxicology 2013; 306:108-13. [PMID: 23435180 DOI: 10.1016/j.tox.2013.02.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 02/10/2013] [Accepted: 02/12/2013] [Indexed: 01/09/2023]
Abstract
The breast cancer resistance protein (Bcrp) is an efflux transporter that participates in the biliary and renal excretion of drugs and environmental chemicals. Recent evidence suggests that pharmacological activation of the peroxisome proliferator activated receptor alpha (PPARα) can up-regulate the hepatic expression of Bcrp. The current study investigated the regulation of hepatic and renal Bcrp mRNA and protein in mice treated with the PPARα agonist perfluorooctanoic acid (PFOA) and the ability of PFOA to alter human BCRP function in vitro. Bcrp mRNA and protein expression were quantified in the livers and kidneys of male C57BL/6 mice treated with vehicle or PFOA (1 or 3mg/kg/day oral gavage) for 7 days. PFOA treatment increased liver weights as well as the hepatic mRNA and protein expression of the PPARα target gene, cytochrome P450 4a14. Compared to vehicle-treated control mice, PFOA increased hepatic Bcrp mRNA and protein between 1.5- and 3-fold. Immunofluorescent staining confirmed enhanced canalicular Bcrp staining in liver sections from PFOA-treated mice. The kidney expression of cytochrome P450 4a14 mRNA, but not Bcrp, was increased in mice treated with PFOA. Micromolar concentrations of PFOA decreased human BCRP ATPase activity and inhibited BCRP-mediated transport in inverted membrane vesicles. Together, these studies demonstrate that PFOA induces hepatic Bcrp expression in mice and may inhibit human BCRP transporter function at concentrations that exceed levels observed in humans.
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Misra P, Viswakarma N, Reddy JK. Peroxisome proliferator-activated receptor-α signaling in hepatocarcinogenesis. Subcell Biochem 2013; 69:77-99. [PMID: 23821144 DOI: 10.1007/978-94-007-6889-5_5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Peroxisomes are subcellular organelles that are found in the cytoplasm of most animal cells. They perform diverse metabolic functions, including H2O2-derived respiration, β-oxidation of fatty acids, and cholesterol metabolism. Peroxisome proliferators are a large class of structurally dissimilar industrial and pharmaceutical chemicals that were originally identified as inducers of both the size and the number of peroxisomes in rat and mouse livers or hepatocytes in vitro. Exposure to peroxisome proliferators leads to a stereotypical orchestration of adaptations consisting of hepatocellular hypertrophy and hyperplasia, and transcriptional induction of fatty acid metabolizing enzymes regulated in parallel with peroxisome proliferation. Chronic exposure to peroxisome proliferators causes liver tumors in both male and female mice and rats. Evidence indicates a pivotal role for a subset of nuclear receptor superfamily members, called peroxisome proliferator-activated receptors (PPARs), in mediating energy metabolism. Upon activation, PPARs regulate the expression of genes involved in lipid metabolism and peroxisome proliferation, as well as genes involved in cell growth. In this review, we describe the molecular mode of action of PPAR transcription factors, including ligand binding, interaction with specific DNA response elements, transcriptional activation, and cross talk with other signaling pathways. We discuss the evidence that suggests that PPARα and transcriptional coactivator Med1/PBP, a key subunit of the Mediator complex play a central role in mediating hepatic steatosis to hepatocarcinogenesis. Disproportionate increases in H2O2-generating enzymes generates excess reactive oxygen species resulting in sustained oxidative stress and progressive endoplasmic reticulum (ER) stress with activation of unfolded protein response signaling. Thus, these major contributors coupled with hepatocellular proliferation are the key players of peroxisome proliferators-induced hepatocarcinogenesis.
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Affiliation(s)
- Parimal Misra
- Department of Biology, Dr. Reddy's Institute of Life Sciences, An Associate Institute of University of Hyderabad, Gachibowli, Hyderabad, 500046, India,
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40
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Arias E. Effects of the peroxisome proliferator di(2-ethylhexyl)phthalate on cell turnover and peroxisome proliferation in primary chick embryo hepatocytes. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2012; 31:2856-60. [PMID: 23001933 DOI: 10.1002/etc.2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 07/07/2012] [Accepted: 08/16/2012] [Indexed: 05/24/2023]
Abstract
The peroxisome proliferator (PP) di(2-ethylhexyl)phthalate (DEHP) is widely used as a plasticizer and can contaminate air, water, and soil. As yet, no data have been published on its potential to induce changes in cell growth of nonmammalian hepatocytes. In the present study, the effects of DEHP on cell turnover and induction of peroxisome proliferation were evaluated in primary hepatocyte cultures from chick embryos. Cells were treated after attachment with 0, 25, 50, 75, and 100 µM DEHP for up to 96 h. S-phase increased significantly (p < 0.01) from a background level of 5.5 ± 0.1% in solvent-control hepatocytes to a maximum level of 7.1 ± 0.1% in cells exposed for 48 h to 100 µM DEHP and decreased to near 6% by 96 h. Lower (p < 0.05) levels of induction were seen at 50 and 75 µM DEHP. Spontaneous apoptosis showed a slight (p < 0.05) decrease in hepatocytes treated with ≥75 µM dosages, as measured at 72 to 96 h. Induction of peroxisome proliferation was observed for cultures treated with ≥75 µM dosages at 48 h onwards. The results of the present study indicate that avian species may be responsive to the effects of PPs and may thus be affected by the presence of DEHP in the environment, but that this species is less sensitive than rodents.
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Affiliation(s)
- Elio Arias
- Department of Bioscience, State University of Milan, Milan, Italy.
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41
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In vitro inhibition of mouse and rat glutathione S-transferases by di(2-ethylhexyl) phthalate, mono(2-ethylhexyl) phthalate, 2-ethylhexanol, 2-ethylhexanoic acid and clofibric acid. Toxicol In Vitro 2012; 5:207-10. [PMID: 20732017 DOI: 10.1016/0887-2333(91)90019-a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/1990] [Revised: 11/06/1990] [Indexed: 11/22/2022]
Abstract
The in vitro inhibitory response of mouse and rat liver cytosolic glutathione S-transferase (GST) activities using the substrates 1,2-dichloro-4-nitrobenzene (DCNB) and 1,2-epoxy-3-(p-nitrophenoxy)propane (ENPP) was determined for the peroxisome proliferators di(2-ethylhexyl) phthalate (DEHP), mono(2-ethylhexyl) phthalate (MEHP), 2-ethylhexanol, 2-ethylhexanoic acid and clofibric acid. MEHP was a potent inhibitor of GST activities in both species, with IC(50)s for DCNB and ENPP of 0.34 and 0.10 mm in the mouse, and 0.32 and 0.88 mm in the rat, respectively. DEHP demonstrated substrate specificity; it inhibited the DCNB-transferase with IC(50)s of 1.05 and 0.55 mm in the mouse and rat, respectively. The other compounds were moderate to weak inhibitors. The inhibitory potency ranking of these compounds was qualitatively similar in both species. Quantitatively, the DCNB-transferase was more sensitive in rats, while ENPP-transferase was more sensitive in mice. The in vitro inhibition may explain, in part, decreases in GST activity seen in vivo following treatment with these compounds. The finding of low IC(50)s for the inhibition of GST activity(s) by MEHP and DEHP in the rat and mouse livers strongly suggests that further studies should be conducted to test for the potential of these compounds to inhibit human liver GST.
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Bhattacharya P, Keating AF. Impact of environmental exposures on ovarian function and role of xenobiotic metabolism during ovotoxicity. Toxicol Appl Pharmacol 2012; 261:227-35. [PMID: 22531813 DOI: 10.1016/j.taap.2012.04.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/04/2012] [Accepted: 04/05/2012] [Indexed: 11/19/2022]
Abstract
The mammalian ovary is a heterogeneous organ and contains oocyte-containing follicles at varying stages of development. The most immature follicular stage, the primordial follicle, comprises the ovarian reserve and is a finite number, defined at the time of birth. Depletion of all follicles within the ovary leads to reproductive senescence, known as menopause. A number of chemical classes can destroy follicles, thus hastening entry into the menopausal state. The ovarian response to chemical exposure can determine the extent of ovotoxicity that occurs. Enzymes capable of bioactivating as well as detoxifying xenobiotics are expressed in the ovary and their impact on ovotoxicity has been partially characterized for trichloroethylene, 7,12-dimethylbenz[a]anthracene, and 4-vinylcyclohexene. This review will discuss those studies, as well as illustrate where knowledge gaps remain for chemicals that have also been established as ovotoxicants.
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Youssef R, Hegazy RA, Fawzy MM, Abdel Halim DM, Nabil N, Sayed SS, Shaker OG. Peroxisome proliferator-activated receptor gamma, a possible culprit in mycosis fungoides: an immunohistochemical study. J Eur Acad Dermatol Venereol 2011; 26:1522-32. [PMID: 22112149 DOI: 10.1111/j.1468-3083.2011.04333.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND It still remains debatable whether peroxisome proliferator-activated receptor gamma (PPARγ) is pro- or antineoplastic, and its exact role in mycosis fungoides (MF) remains unclear. OBJECTIVE This prospective comparative study aimed to investigate the expression of PPARγ in MF and compare it with psoriatics and controls in a trial to deduce its possible role in MF. Also, we tried to clarify the relation between PPARγ and Bcl-2 in MF. METHODS Twenty MF patients, 20 psoriatic patients and 20 controls were included. All participants underwent a skin biopsy, and immunohistochemical staining for both PPARγ and Bcl-2 were performed. Western blot analysis was performed for detection of both PPARγ and Bcl-2. RESULTS The mean area per cent of PPARγ measured in the MF patients (57.1217±9.502417) was significantly higher (P<0.001) when compared with that of both the psoriatics (2.989±1.723) and controls (35.9357±8.1789). The mean area per cent of Bcl-2 in MF patients (9.3763±6.6328) was significantly higher (P<0.001) than that of both the psoriatics (2.35±1.35) and the controls (0.73105±0.5302)]. Our results were confirmed using the western blot analysis. We detected a highly significant positive correlation between the PPARγ and Bcl-2 mean area per cents in all patients. In our MF patients, both parameters were also positively correlated with the age of the patient, duration and stage of MF (P<0.05). CONCLUSION Our data suggest a possible role for PPARγ in the pathogenesis of MF possibly through several mechanisms, one of which might be conferring upon the lymphoma cells, a survival advantage at least partially through up regulating Bcl-2.
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Affiliation(s)
- R Youssef
- Department of Dermatology, Kasr AlAini Hospital, Cairo University, Cairo, Egypt
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Holth TF, Beckius J, Zorita I, Cajaraville MP, Hylland K. Assessment of lysosomal membrane stability and peroxisome proliferation in the head kidney of Atlantic cod (Gadus morhua) following long-term exposure to produced water components. MARINE ENVIRONMENTAL RESEARCH 2011; 72:127-134. [PMID: 21821279 DOI: 10.1016/j.marenvres.2011.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/05/2011] [Accepted: 07/11/2011] [Indexed: 05/31/2023]
Abstract
There is a need for sensitive biological effect methods by which to detect impacts of chronic exposure to low concentrations of contaminants. Two methods shown to be potentially useful for monitoring purposes in fish include lysosomal membrane stability and peroxisome proliferation. These biological endpoints were assessed in Atlantic cod (Gadus morhua) head kidney following exposure to a mixture of produced water components including polycyclic aromatic hydrocarbons, phenol, and alkylphenols. Lysosomal damage of head kidney cells occurred within the first two weeks and did not recover during the entire exposure period (32 weeks). Lysosomal membrane stability was not affected by gender and was responsive at low concentrations of contamination, indicating that lysosomal membrane stability measured in the head kidney could be a useful biomarker for effects of offshore pollution. Peroxisome proliferation, measured as acyl-CoA oxidase activity in the head kidney, appeared to be a potential biomarker in male cod exposed less than 16 weeks.
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Affiliation(s)
- T F Holth
- University of Oslo, Department of Biology, Norway.
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Omiecinski CJ, Vanden Heuvel JP, Perdew GH, Peters JM. Xenobiotic metabolism, disposition, and regulation by receptors: from biochemical phenomenon to predictors of major toxicities. Toxicol Sci 2011; 120 Suppl 1:S49-75. [PMID: 21059794 PMCID: PMC3145385 DOI: 10.1093/toxsci/kfq338] [Citation(s) in RCA: 240] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 11/01/2010] [Indexed: 02/07/2023] Open
Abstract
To commemorate the 50th anniversary of the Society of Toxicology, this special edition article reviews the history and current scope of xenobiotic metabolism and transport, with special emphasis on the discoveries and impact of selected "xenobiotic receptors." This overall research realm has witnessed dynamic development in the past 50 years, and several of the key milestone events that mark the impressive progress in these areas of toxicological sciences are highlighted. From the initial observations regarding aspects of drug metabolism dating from the mid- to late 1800's, the area of biotransformation research witnessed seminal discoveries in the mid-1900's and onward that are remarkable in retrospect, including the discovery and characterization of the phase I monooxygenases, the cytochrome P450s. Further research uncovered many aspects of the biochemistry of xenobiotic metabolism, expanding to phase II conjugation and phase III xenobiotic transport. This led to hallmark developments involving integration of genomic technologies to elucidate the basis for interindividual differences in response to xenobiotic exposures and discovery of nuclear and soluble receptor families that selectively "sense" the chemical milieu of the mammalian cell and orchestrate compensatory changes in gene expression programming to accommodate complex xenobiotic exposures. This review will briefly summarize these developments and investigate the expanding roles of xenobiotic receptor biology in the underlying basis of toxicological response to chemical agents.
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Affiliation(s)
- Curtis J Omiecinski
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, Penn State University, University Park, Pennsylvania 16802, USA.
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Reumann S, Voitsekhovskaja O, Lillo C. From signal transduction to autophagy of plant cell organelles: lessons from yeast and mammals and plant-specific features. PROTOPLASMA 2010; 247:233-56. [PMID: 20734094 DOI: 10.1007/s00709-010-0190-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Accepted: 07/28/2010] [Indexed: 05/08/2023]
Abstract
Autophagy is an evolutionarily conserved intracellular process for the vacuolar degradation of cytoplasmic constituents. The central structures of this pathway are newly formed double-membrane vesicles (autophagosomes) that deliver excess or damaged cell components into the vacuole or lysosome for proteolytic degradation and monomer recycling. Cellular remodeling by autophagy allows organisms to survive extensive phases of nutrient starvation and exposure to abiotic and biotic stress. Autophagy was initially studied by electron microscopy in diverse organisms, followed by molecular and genetic analyses first in yeast and subsequently in mammals and plants. Experimental data demonstrate that the basic principles, mechanisms, and components characterized in yeast are conserved in mammals and plants to a large extent. However, distinct autophagy pathways appear to differ between kingdoms. Even though direct information remains scarce particularly for plants, the picture is emerging that the signal transduction cascades triggering autophagy and the mechanisms of organelle turnover evolved further in higher eukaryotes for optimization of nutrient recycling. Here, we summarize new research data on nitrogen starvation-induced signal transduction and organelle autophagy and integrate this knowledge into plant physiology.
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Affiliation(s)
- Sigrun Reumann
- Centre for Organelle Research, University of Stavanger, 4021 Stavanger, Norway.
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Cunningham ML, Collins BJ, Hejtmancik MR, Herbert RA, Travlos GS, Vallant MK, Stout MD. Effects of the PPARα Agonist and Widely Used Antihyperlipidemic Drug Gemfibrozil on Hepatic Toxicity and Lipid Metabolism. PPAR Res 2010; 2010:681963. [PMID: 20953357 PMCID: PMC2952818 DOI: 10.1155/2010/681963] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/13/2010] [Accepted: 07/29/2010] [Indexed: 11/17/2022] Open
Abstract
Gemfibrozil is a widely prescribed hypolipidemic agent in humans and a peroxisome proliferator and liver carcinogen in rats. Three-month feed studies of gemfibrozil were conducted by the National Toxicology Program (NTP) in male Harlan Sprague-Dawley rats, B6C3F1 mice, and Syrian hamsters, primarily to examine mechanisms of hepatocarcinogenicity. There was morphologic evidence of peroxisome proliferation in rats and mice. Increased hepatocyte proliferation was observed in rats, primarily at the earliest time point. Increases in peroxisomal enzyme activities were greatest in rats, intermediate in mice, and least in hamsters. These studies demonstrate that rats are most responsive while hamsters are least responsive. These events are causally related to hepatotoxicity and hepatocarcinogenicity of gemfibrozil in rodents via peroxisome proliferator activated receptor-α (PPARα) activation; however, there is widespread evidence that activation of PPARα in humans results in expression of genes involved in lipid metabolism, but not in hepatocellular proliferation.
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Affiliation(s)
- Michael L. Cunningham
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Bradley J. Collins
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Milton R. Hejtmancik
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Ronald A. Herbert
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Gregory S. Travlos
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Molly K. Vallant
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Matthew D. Stout
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, Research Triangle Park, NC 27709, USA
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Pyper SR, Viswakarma N, Yu S, Reddy JK. PPARalpha: energy combustion, hypolipidemia, inflammation and cancer. NUCLEAR RECEPTOR SIGNALING 2010; 8:e002. [PMID: 20414453 PMCID: PMC2858266 DOI: 10.1621/nrs.08002] [Citation(s) in RCA: 291] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 03/04/2010] [Indexed: 12/11/2022]
Abstract
The peroxisome proliferator-activated receptor alpha (PPARalpha, or NR1C1) is a nuclear hormone receptor activated by a structurally diverse array of synthetic chemicals known as peroxisome proliferators. Endogenous activation of PPARalpha in liver has also been observed in certain gene knockout mouse models of lipid metabolism, implying the existence of enzymes that either generate (synthesize) or degrade endogenous PPARalpha agonists. For example, substrates involved in fatty acid oxidation can function as PPARalpha ligands. PPARalpha serves as a xenobiotic and lipid sensor to regulate energy combustion, hepatic steatosis, lipoprotein synthesis, inflammation and liver cancer. Mainly, PPARalpha modulates the activities of all three fatty acid oxidation systems, namely mitochondrial and peroxisomal beta-oxidation and microsomal omega-oxidation, and thus plays a key role in energy expenditure. Sustained activation of PPARalpha by either exogenous or endogenous agonists leads to the development of hepatocellular carcinoma resulting from sustained oxidative and possibly endoplasmic reticulum stress and liver cell proliferation. PPARalpha requires transcription coactivator PPAR-binding protein (PBP)/mediator subunit 1(MED1) for its transcriptional activity.
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Affiliation(s)
| | | | | | - Janardan K. Reddy
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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Asano J, Kudo T, Shimizu T, Fan Y, Nanashima N, Yamana D, Miura T, Yamada T, Tsuchida S. Histone acetylation and steroid receptor coactivator expression during clofibrate-induced rat hepatocarcinogenesis. Cancer Sci 2010; 101:869-75. [PMID: 20132223 PMCID: PMC11158118 DOI: 10.1111/j.1349-7006.2009.01460.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Peroxisome proliferators (PPs), non-genotoxic rodent carcinogens, cause the induction of the peroxisomal fatty acid beta-oxidation system, including bifunctional enzyme (BE) and 3-ketoacyl-CoA thiolase (TH), in the liver. GST M1 gene is polymorphic in Sprague-Dawley rats, NC- and KS-type. The KS-type rats showed enhanced susceptibility to ethyl-alpha-chlorophenoxyisobutyrate (clofibrate, CF), one of the PPs. The degree of BE induction was higher in the KS-type and preneoplastic foci developed after 6-8 weeks of treatment, whereas no foci developed in the NC-type. In the preset study, factors involved in different BE inducibility were investigated. There were no differences in hepatic peroxisome proliferator-activated receptor (PPAR) alpha levels between them. Among various coactivators for PPARalpha, only steroid receptor coactivator (SRC)-3 level was higher in the KS-type. To investigate the association between PPARalpha and SRC-3 or other proteins, nuclear extracts from CF-treated livers were applied to a PPARalpha column. In the KS-type, 110, 72, and 42 kDa proteins were bound and these were identified as SRC-3, BE, and TH, respectively. EMSA supported the binding of these proteins to PPARalpha associated to the BE enhancer in CF-treated KS-type, but not in the NC-type. Histone H3 acetylation was increased 11-fold in the KS-type by CF treatment but not in the NC-type. As BE and TH are responsible for acetyl-CoA production and SRC-3 possesses a histone acetyltransferase activity, these results suggest that enhanced BE induction in the KS-type livers is due to acetylation-mediated transcriptional activation and epigenetic mechanisms might be involved in CF-induced rat hepatocarcinogenesis.
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Affiliation(s)
- Jumpei Asano
- Department of Biochemistry and Genome Biology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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Ren H, Aleksunes LM, Wood C, Vallanat B, George MH, Klaassen CD, Corton JC. Characterization of peroxisome proliferator-activated receptor alpha--independent effects of PPARalpha activators in the rodent liver: di-(2-ethylhexyl) phthalate also activates the constitutive-activated receptor. Toxicol Sci 2009; 113:45-59. [PMID: 19850644 DOI: 10.1093/toxsci/kfp251] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Peroxisome proliferator chemicals (PPC) are thought to mediate their effects in rodents on hepatocyte growth and liver cancer through the nuclear receptor peroxisome proliferator-activated receptor (PPAR) alpha. Recent studies indicate that the plasticizer di-(2-ethylhexyl) phthalate (DEHP) increased the incidence of liver tumors in PPARalpha-null mice. We hypothesized that some PPC, including DEHP, induce transcriptional changes independent of PPARalpha but dependent on other nuclear receptors, including the constitutive-activated receptor (CAR) that mediates phenobarbital (PB) effects on hepatocyte growth and liver tumor induction. To determine the potential role of CAR in mediating effects of PPC, a meta-analysis was performed on transcript profiles from published studies in which rats and mice were exposed to PPC and compared the profiles to those produced by exposure to PB. Valproic acid, clofibrate, and DEHP in rat liver and DEHP in mouse liver induced genes, including Cyp2b family members that are known to be regulated by CAR. Examination of transcript changes by Affymetrix ST 1.0 arrays and reverse transcription-PCR in the livers of DEHP-treated wild-type, PPARalpha-null, and CAR-null mice demonstrated that (1) most (approximately 94%) of the transcriptional changes induced by DEHP were PPARalpha-dependent, (2) many PPARalpha-independent genes overlapped with those regulated by PB, (3) induction of genes Cyp2b10, Cyp3a11, and metallothionine-1 by DEHP was CAR dependent but PPARalpha-independent, and (4) induction of a number of genes (Cyp8b1, Gstm4, and Gstm7) was independent of both CAR and PPARalpha. Our results indicate that exposure to PPARalpha activators including DEHP leads to activation of multiple nuclear receptors in the rodent liver.
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Affiliation(s)
- Hongzu Ren
- National Health and Environmental Effects Research Lab Toxicogenomics Core, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
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