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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, Hoogenboom L(R, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Wallace H, Benford D, Hart A, Schroeder H, Rose M, Vrijheid M, Kouloura E, Bordajandi LR, Riolo F, Vleminckx C. Update of the scientific opinion on tetrabromobisphenol A (TBBPA) and its derivatives in food. EFSA J 2024; 22:e8859. [PMID: 39010865 PMCID: PMC11247339 DOI: 10.2903/j.efsa.2024.8859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024] Open
Abstract
The European Commission asked EFSA to update its 2011 risk assessment on tetrabromobisphenol A (TBBPA) and five derivatives in food. Neurotoxicity and carcinogenicity were considered as the critical effects of TBBPA in rodent studies. The available evidence indicates that the carcinogenicity of TBBPA occurs via non-genotoxic mechanisms. Taking into account the new data, the CONTAM Panel considered it appropriate to set a tolerable daily intake (TDI). Based on decreased interest in social interaction in male mice, a lowest observed adverse effect level (LOAEL) of 0.2 mg/kg body weight (bw) per day was identified and selected as the reference point for the risk characterisation. Applying the default uncertainty factor of 100 for inter- and intraspecies variability, and a factor of 3 to extrapolate from the LOAEL to NOAEL, a TDI for TBBPA of 0.7 μg/kg bw per day was established. Around 2100 analytical results for TBBPA in food were used to estimate dietary exposure for the European population. The most important contributors to the chronic dietary LB exposure to TBBPA were fish and seafood, meat and meat products and milk and dairy products. The exposure estimates to TBBPA were all below the TDI, including those estimated for breastfed and formula-fed infants. Accounting for the uncertainties affecting the assessment, the CONTAM Panel concluded with 90%-95% certainty that the current dietary exposure to TBBPA does not raise a health concern for any of the population groups considered. There were insufficient data on the toxicity of any of the TBBPA derivatives to derive reference points, or to allow a comparison with TBBPA that would support assignment to an assessment group for the purposes of combined risk assessment.
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Khani L, Martin L, Pułaski Ł. Cellular and physiological mechanisms of halogenated and organophosphorus flame retardant toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 897:165272. [PMID: 37406685 DOI: 10.1016/j.scitotenv.2023.165272] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/19/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
Flame retardants (FRs) are chemical substances used to inhibit the spread of fire in numerous industrial applications, and their abundance in modern manufactured products in the indoor and outdoor environment leads to extensive direct and food chain exposure of humans. Although once considered relatively non-toxic, FRs are demonstrated by recent literature to have disruptive effects on many biological processes, including signaling pathways, genome stability, reproduction, and immune system function. This review provides a summary of research investigating the impact of major groups of FRs, including halogenated and organophosphorus FRs, on animals and humans in vitro and/or in vivo. We put in focus those studies that explained or referenced the modes of FR action at the level of cells, tissues and organs. Since FRs are highly hydrophobic chemicals, their biophysical and biochemical modes of action usually involve lipophilic interactions, e.g. with biological membranes or elements of signaling pathways. We present selected toxicological information about these molecular actions to show how they can lead to damaging membrane integrity, damaging DNA and compromising its repair, changing gene expression, and cell cycle as well as accelerating cell death. Moreover, we indicate how this translates to deleterious bioactivity of FRs at the physiological level, with disruption of hormonal action, dysregulation of metabolism, adverse effects on male and female reproduction as well as alteration of normal pattern of immunity. Concentrating on these subjects, we make clear both the advances in knowledge in recent years and the remaining gaps in our understanding, especially at the mechanistic level.
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Affiliation(s)
- Leila Khani
- Laboratory of Transcriptional Regulation, Institute of Medical Biology PAS, Lodz, Poland; Bio-Med-Chem Doctoral School of the University of Lodz and Lodz Institutes of the Polish Academy of Sciences, Lodz, Poland
| | - Leonardo Martin
- Laboratory of Transcriptional Regulation, Institute of Medical Biology PAS, Lodz, Poland; Department of Biochemistry and Molecular Biology, Federal University of São Paulo, São Paulo, Brazil
| | - Łukasz Pułaski
- Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland; Laboratory of Transcriptional Regulation, Institute of Medical Biology PAS, Lodz, Poland.
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Holuka C, Morel C, Roth S, Lamartinière Y, Mériaux SB, Paoli J, Guébels P, Duca RC, Godderis L, van Nieuwenhuyse A, Kremarik-Bouillaud P, Cariou R, Emond C, Schroeder H, Turner JD, Grova N. The epigenetic hallmark of early-life α-hexabromocyclododecane exposure: From cerebellar 6-mA levels to locomotor performance in adulthood. ENVIRONMENT INTERNATIONAL 2023; 178:108103. [PMID: 37494814 DOI: 10.1016/j.envint.2023.108103] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023]
Abstract
There is a growing evidence that methylation at the N6 position of adenine (6-mA), whose modulation occurs primarily during development, would be a reliable epigenetic marker in eukaryotic organisms. The present study raises the question as to whether early-life exposure to α-hexabromocyclododecane (α-HBCDD), a brominated flame retardant, may trigger modifications in 6-mA epigenetic hallmarks in the brain during the development which, in turn could affect the offspring behaviour in adulthood. Pregnant Wistar rats were split into two groups: control and α-HBCDD (66 ng/kg/per os, G0-PND14). At PND1, α-HBCDD levels were assessed in brain and liver by LC-MS/MS. At PND14, DNA was isolated from the offspring's cerebellum. DNA methylation was measured by 6-mA-specific immunoprecipitation and Illumina® sequencing (MEDIP-Seq). Locomotor activity was finally evaluated at PND120. In our early-life exposure model, we confirmed that α-HBCDD can cross the placental barrier and be detected in pups at birth. An obvious post-exposure phenotype with locomotor deficits was observed when the rats reached adulthood. This was accompanied by sex-specific over-methylation of genes involved in the insulin signaling pathway, MAPK signaling pathway as well as serotonergic and GABAergic synapses, potentially altering the normal process of neurodevelopment with consequent motor impairments crystalized at adulthood.
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Affiliation(s)
- Cyrielle Holuka
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg; Faculty of Science, University of Luxembourg, L-4365 Belval, Luxembourg.
| | - Chloé Morel
- Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France.
| | - Sarah Roth
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg.
| | - Yordenca Lamartinière
- Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France.
| | - Sophie B Mériaux
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg.
| | - Justine Paoli
- Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France.
| | - Pauline Guébels
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg.
| | - Radu C Duca
- Department of Health Protection, National Health Laboratory (LNS), Dudelange, Luxembourg; Centre for Environment and Health, University of Leuven (KU Leuven), Leuven, Belgium.
| | - Lode Godderis
- Centre for Environment and Health, University of Leuven (KU Leuven), Leuven, Belgium; IDEWE, External Service for Prevention and Protection at Work, Heverlee 3001, Belgium.
| | - An van Nieuwenhuyse
- Department of Health Protection, National Health Laboratory (LNS), Dudelange, Luxembourg; Centre for Environment and Health, University of Leuven (KU Leuven), Leuven, Belgium.
| | - Pascaline Kremarik-Bouillaud
- UMR Inserm 1256 nGERE, Nutrition-Génétique et exposition aux risques environnementaux, Institute of Medical Research (Pôle BMS), University of Lorraine, B.P. 184, 54511 Nancy, France.
| | | | - Claude Emond
- PKSH Inc., Crabtree, Quebec, Canada; School of Public Health, DSEST, University of Montreal, Montreal, Quebec, Canada.
| | - Henri Schroeder
- Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France; UMR Inserm 1256 nGERE, Nutrition-Génétique et exposition aux risques environnementaux, Institute of Medical Research (Pôle BMS), University of Lorraine, B.P. 184, 54511 Nancy, France.
| | - Jonathan D Turner
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg.
| | - Nathalie Grova
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg; Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France; UMR Inserm 1256 nGERE, Nutrition-Génétique et exposition aux risques environnementaux, Institute of Medical Research (Pôle BMS), University of Lorraine, B.P. 184, 54511 Nancy, France.
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Barańska A, Bukowska B, Michałowicz J. Determination of Apoptotic Mechanism of Action of Tetrabromobisphenol A and Tetrabromobisphenol S in Human Peripheral Blood Mononuclear Cells: A Comparative Study. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27186052. [PMID: 36144785 PMCID: PMC9500834 DOI: 10.3390/molecules27186052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 11/16/2022]
Abstract
Background: Tetrabromobisphenol A (TBBPA) is the most commonly used brominated flame retardant (BFR) in the industry. TBBPA has been determined in environmental samples, food, tap water, dust as well as outdoor and indoor air and in the human body. Studies have also shown the toxic potential of this substance. In search of a better and less toxic BFR, tetrabromobisphenol S (TBBPS) has been developed in order to replace TBBPA in the industry. There is a lack of data on the toxic effects of TBBPS, while no study has explored apoptotic mechanism of action of TBBPA and TBBPS in human leukocytes. Methods: The cells were separated from leucocyte-platelet buffy coat and were incubated with studied compounds in concentrations ranging from 0.01 to 50 µg/mL for 24 h. In order to explore the apoptotic mechanism of action of tested BFRs, phosphatidylserine externalization at cellular membrane (the number of apoptotic cells), cytosolic calcium ion and transmembrane mitochondrial potential levels, caspase-8, -9 and -3 activation, as well as PARP-1 cleavage, DNA fragmentation and chromatin condensation in PBMCs were determined. Results: TBBPA and TBBPS triggered apoptosis in human PBMCs as they changed all tested parameters in the incubated cells. It was also observed that the mitochondrial pathway was mainly involved in the apoptotic action of studied compounds. Conclusions: It was found that TBBPS, and more strongly TBBPA, triggered apoptosis in human PBMCs. Generally, the mitochondrial pathway was involved in the apoptotic action of tested compounds; nevertheless, TBBPS more strongly than TBBPA caused intrinsic pathway activation.
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Rigby H, Dowding A, Fernandes A, Humphries D, Jones NR, Lake I, Petch RG, Reynolds CK, Rose M, Smith SR. Concentrations of organic contaminants in industrial and municipal bioresources recycled in agriculture in the UK. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:142787. [PMID: 33246727 DOI: 10.1016/j.scitotenv.2020.142787] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 08/14/2020] [Accepted: 09/30/2020] [Indexed: 06/12/2023]
Abstract
Many types of bioresource materials are beneficially recycled in agriculture for soil improvement and as alternative bedding materials for livestock, but they also potentially transfer contaminants into plant and animal foods. Representative types of industrial and municipal bioresources were selected to assess the extent of organic chemical contamination, including: (i) land applied materials: treated sewage sludge (biosolids), meat and bone meal ash (MBMA), poultry litter ash (PLA), paper sludge ash (PSA) and compost-like-output (CLO), and (ii) bedding materials: recycled waste wood (RWW), dried paper sludge (DPS), paper sludge ash (PSA) and shredded cardboard. The materials generally contained lower concentrations of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) relative to earlier reports, indicating the decline in environmental emissions of these established contaminants. However, concentrations of polycyclic aromatic hydrocarbons (PAHs) remain elevated in biosolids samples from urban catchments. Polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) were present in larger amounts in biosolids and CLO compared to their chlorinated counterparts and hence are of potentially greater significance in contemporary materials. The presence of non-ortho-polychlorinated biphenyls (PCBs) in DPS was probably due to non-legacy sources of PCBs in paper production. Flame retardent chemicals were one of the most significant and extensive groups of contaminants found in the bioresource materials. Decabromodiphenylether (deca-BDE) was the most abundant polybrominated diphenyl ether (PBDE) and may explain the formation and high concentrations of PBDD/Fs detected. Emerging flame retardant compounds, including: decabromodiphenylethane (DBDPE) and organophosphate flame retardants (OPFRs), were also detected in several of the materials. The profile of perfluoroalkyl substances (PFAS) depended on the type of waste category; perfluoroundecanoic acid (PFUnDA) was the most significant PFAS for DPS, whereas perfluorooctane sulfonate (PFOS) was dominant in biosolids and CLO. The concentrations of polychlorinated alkanes (PCAs) and di-2-ethylhexyl phthalate (DEHP) were generally much larger than the other contaminants measured, indicating that there are major anthropogenic sources of these potentially hazardous chemicals entering the environment. The study results suggest that continued vigilance is required to control emissions and sources of these contaminants to support the beneficial use of secondary bioresource materials.
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Affiliation(s)
- Hannah Rigby
- Imperial College Consultants Ltd., 58 Prince's Gate, Exhibition Road, London SW7 2PG, UK
| | - Alan Dowding
- Chemical Contaminants and Residues Branch, Food Safety Policy, Food Standards Agency, Clive House, 70 Petty France, London SW1H 9EX, UK
| | - Alwyn Fernandes
- The Food and Environment Research Agency (Fera), Sand Hutton, York YO41 1LZ, UK; University of East Anglia, School of Environmental Sciences, Norwich NR4 7TJ, UK
| | - David Humphries
- The University of Reading, School of Agriculture, Policy and Development, Centre for Dairy Research, POB 237, Reading, Berkshire RG6 6AR, UK
| | - Natalia R Jones
- University of East Anglia, School of Environmental Sciences, Norwich NR4 7TJ, UK
| | - Iain Lake
- University of East Anglia, School of Environmental Sciences, Norwich NR4 7TJ, UK
| | - Rupert G Petch
- The Food and Environment Research Agency (Fera), Sand Hutton, York YO41 1LZ, UK
| | - Christopher K Reynolds
- The University of Reading, School of Agriculture, Policy and Development, Centre for Dairy Research, POB 237, Reading, Berkshire RG6 6AR, UK
| | - Martin Rose
- The Food and Environment Research Agency (Fera), Sand Hutton, York YO41 1LZ, UK
| | - Stephen R Smith
- Imperial College Consultants Ltd., 58 Prince's Gate, Exhibition Road, London SW7 2PG, UK.
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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, Hoogenboom L(R, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Wallace H, Benford D, Fürst P, Rose M, Ioannidou S, Nikolič M, Bordajandi LR, Vleminckx C. Update of the risk assessment of hexabromocyclododecanes (HBCDDs) in food. EFSA J 2021; 19:e06421. [PMID: 33732387 PMCID: PMC7938899 DOI: 10.2903/j.efsa.2021.6421] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The European Commission asked EFSA to update its 2011 risk assessment on hexabromocyclododecanes (HBCDDs) in food. HBCDDs, predominantly mixtures of the stereoisomers α-, β- and γ-HBCDD, were widely used additive flame retardants. Concern has been raised because of the occurrence of HBCDDs in the environment, food and in humans. Main targets for toxicity are neurodevelopment, the liver, thyroid hormone homeostasis and the reproductive and immune systems. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour in mice can be considered the critical effects. Based on effects on spontaneous behaviour in mice, the Panel identified a lowest observed adverse effect level (LOAEL) of 0.9 mg/kg body weight (bw) as the Reference Point, corresponding to a body burden of 0.75 mg/kg bw. The chronic intake that would lead to the same body burden in humans was calculated to be 2.35 μg/kg bw per day. The derivation of a health-based guidance value (HBGV) was not considered appropriate. Instead, the margin of exposure (MOE) approach was applied to assess possible health concerns. Over 6,000 analytical results for HBCDDs in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary LB exposure to HBCDDs were fish meat, eggs, livestock meat and poultry. The CONTAM Panel concluded that the resulting MOE values support the conclusion that current dietary exposure to HBCDDs across European countries does not raise a health concern. An exception is breastfed infants with high milk consumption, for which the lowest MOE values may raise a health concern.
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Bowen C, Childers G, Perry C, Martin N, McPherson CA, Lauten T, Santos J, Harry GJ. Mitochondrial-related effects of pentabromophenol, tetrabromobisphenol A, and triphenyl phosphate on murine BV-2 microglia cells. CHEMOSPHERE 2020; 255:126919. [PMID: 32402876 PMCID: PMC8439439 DOI: 10.1016/j.chemosphere.2020.126919] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/18/2020] [Accepted: 04/27/2020] [Indexed: 05/02/2023]
Abstract
The predominant reliance on bromated flame retardants (BFRs) is diminishing with expanded use of alternative organophosphate flame retardants. However, exposure related issues for susceptible populations, the developing, infirmed, or aged, remain given environmental persistence and home-environment detection. In this regard, reports of flame retardant (FR)-related effects on the innate immune system suggest process by which a spectrum of adverse health effects could manifest across the life-span. As representative of the nervous system innate immune system, the current study examined changes in microglia following exposure to representative FRs, pentabromophenol (PBP), tetrabromobisphenol A (2,2',6,6',-tetrabromo-4,4'-isopropylidine diphenol; TBBPA) and triphenyl phosphate (TPP). Following 18hr exposure of murine BV-2 cells, at dose levels resulting in ≥80% viability (10 and 40 μM), limited alterations in pro-inflammatory responses were observed however, changes were observed in mitochondrial respiration. Basal respiration was altered by PBP; ATP-linked respiration by PBP and TBBPA, and maximum respiration by all three FRs. Basal glycolytic rate was altered by PBP and TBBPA and compensatory glycolysis by all three. Phagocytosis was decreased for PBP and TBBPA. NLRP3 inflammasome activation was assessed using BV-2-ASC (apoptosis-associated speck-like protein containing a CARD) reporter cells to visualize aggregate formation. PBP, showed a direct stimulation of aggregate formation and properties as a NLRP3 inflammasome secondary trigger. TBBPA showed indications of possible secondary triggering activity while no changes were seen with TPP. Thus, the data suggests an effect of all three FRs on mitochondria metabolism yet, different functional outcomes including, phagocytic capability and NLRP3 inflammasome activation.
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Affiliation(s)
| | | | | | - Negin Martin
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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Park SY, Choi EM, Suh KS, Kim HS, Chin SO, Rhee SY, Kim DY, Oh S, Chon S. Tetrabromobisphenol A Promotes the Osteoclastogenesis of RAW264.7 Cells Induced by Receptor Activator of NF-kappa B Ligand In Vitro. J Korean Med Sci 2019; 34:e267. [PMID: 31650720 PMCID: PMC6813422 DOI: 10.3346/jkms.2019.34.e267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/05/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Tetrabromobisphenol A (TBBPA), one of the most widely used brominated flame-retardants, is a representative persistent organic pollutants group. Studies on TBBPA toxicity have been conducted using various target cells; however, few studies have investigated TBBPA toxicity in bone cells. Therefore, this study investigated the in vitro effects of TBBPA on osteoclasts, a cell type involved in bone metabolism. METHODS RAW264.7 cells were cultured in medium containing 50 ng/mL receptor activator of nuclear factor kappa B ligand (RANKL) and varying concentrations of TBBPA. To evaluate the effects of TBBPA on the differentiation and function of osteoclasts, osteoclast-specific gene expression, tartrate-resistant acid phosphatase (TRAP) activity, bone resorbing activity, mitochondrial membrane potential (MMP) and mitochondrial superoxide were measured. RESULTS The presence of 20 μ TBBPA significantly increased TRAP activity in RANKL-stimulated RAW264.7 cells, the bone resorbing activity of osteoclasts, and the gene expression of Akt2, nuclear factor of activated T-cells cytoplasmic 1, and chloride channel voltage-sensitive 7. However, TBBPA treatment caused no change in the expression of carbonic anhydrase II, cathepsin K, osteopetrosis-associated transmembrane protein 1, Src, extracellular signal-related kinase, GAB2, c-Fos, or matrix metalloproteinase 9. Furthermore, 20 μ TBBPA caused a significant decrease in MMP and a significant increase in mitochondrial superoxide production. CONCLUSION This study suggests that TBBPA promotes osteoclast differentiation and activity. The mechanism of TBBPA-stimulated osteoclastogenesis might include increased expression of several genes involved in osteoclast differentiation and reactive oxygen species production.
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Affiliation(s)
- So Young Park
- Department of Endocrinology & Metabolism, Kyung Hee University Hospital, Seoul, Korea
| | - Eun Mi Choi
- Department of Endocrinology & Metabolism, Kyung Hee University School of Medicine, Seoul, Korea
| | - Kwang Sik Suh
- Department of Endocrinology & Metabolism, Kyung Hee University School of Medicine, Seoul, Korea
| | - Hyun Sook Kim
- Department of Biomedical Laboratory Science, College of Health and Medical Sciences, Cheongju University, Cheongju, Korea
| | - Sang Ouk Chin
- Department of Endocrinology & Metabolism, Kyung Hee University Hospital, Seoul, Korea
- Department of Endocrinology & Metabolism, Kyung Hee University School of Medicine, Seoul, Korea
| | - Sang Youl Rhee
- Department of Endocrinology & Metabolism, Kyung Hee University Hospital, Seoul, Korea
- Department of Endocrinology & Metabolism, Kyung Hee University School of Medicine, Seoul, Korea
| | - Deog Yoon Kim
- Department of Nuclear Medicine, Kyung Hee University School of Medicine, Seoul, Korea
| | - Seungjoon Oh
- Department of Endocrinology & Metabolism, Kyung Hee University Hospital, Seoul, Korea
- Department of Endocrinology & Metabolism, Kyung Hee University School of Medicine, Seoul, Korea
| | - Suk Chon
- Department of Endocrinology & Metabolism, Kyung Hee University Hospital, Seoul, Korea
- Department of Endocrinology & Metabolism, Kyung Hee University School of Medicine, Seoul, Korea.
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Xie X, Ma L, Zhou Y, Shen W, Xu D, Dou J, Shen B, Zhou C. Polysaccharide enhanced NK cell cytotoxicity against pancreatic cancer via TLR4/MAPKs/NF-κB pathway in vitro/vivo. Carbohydr Polym 2019; 225:115223. [PMID: 31521276 DOI: 10.1016/j.carbpol.2019.115223] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/17/2019] [Accepted: 08/19/2019] [Indexed: 12/14/2022]
Abstract
A polysaccharide isolated from Strongylocentrotus nudus eggs (SEP) reportedly displays immune activity in vivo. Here, its effect and underlying mechanism in the treatment of pancreatic cancer were investigated. SEP obviously inhibited pancreatic cancer growth by activating NK cells in vitro/vivo via TLR4/MAPKs/NF-κB signaling pathway, The tumor inhibitory rate achieved to 44.5% and 50.8% at a dose of 40 mg/kg in Bxpc-3 and SW1990 nude mice, respectively. Moreover, SEP obviously augmented the Gemcitabine (GEM) antitumor effect by upregulating NKG2D, which improved the sensitivity of NK cells targeting to its ligand MICA; meanwhile, the antitumor inhibitory rate was 68.6% in BxPC-3 tumor-bearing mice. Moreover, SEP reversed GEM-induced apoptosis and atrophy in both spleen and bone marrow via suppressing ROS secretion in vivo. These results suggested that pancreatic cancer was effectively inhibited by SEP-enhanced NK cytotoxicity mediated primarily through TLR4/MAPKs/NF-κB signaling pathway, representing a potential immunotherapy candidate for the treatment of pancreatic cancer.
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Affiliation(s)
- Xin Xie
- School of Life Science and Technology, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, PR China
| | - Lingman Ma
- School of Life Science and Technology, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, PR China
| | - Yiran Zhou
- Department of General Surgery, Rui Jin Hospital, Research Institute of Pancreatic Diseases, School of Medicine, Shanghai JiaoTong University, Shanghai, 200025, PR China
| | - Wen Shen
- School of Life Science and Technology, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, PR China
| | - Duiyue Xu
- School of Life Science and Technology, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, PR China
| | - Jie Dou
- School of Life Science and Technology, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, PR China
| | - Baiyong Shen
- Department of General Surgery, Rui Jin Hospital, Research Institute of Pancreatic Diseases, School of Medicine, Shanghai JiaoTong University, Shanghai, 200025, PR China.
| | - Changlin Zhou
- School of Life Science and Technology, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, PR China.
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Zhang Y, Wang X, Chen C, An J, Shang Y, Li H, Xia H, Yu J, Wang C, Liu Y, Guo S. Regulation of TBBPA-induced oxidative stress on mitochondrial apoptosis in L02 cells through the Nrf2 signaling pathway. CHEMOSPHERE 2019; 226:463-471. [PMID: 30951941 DOI: 10.1016/j.chemosphere.2019.03.167] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 06/09/2023]
Abstract
Tetrabromobisphenol A (TBBPA) is a commonly used brominated flame retardant, which has a wide range of toxic effects on organisms. This study investigated the cytotoxic effects on human hepatocytes (L02 cells) after treated with 0, 5, 10, 20, and 40 μM of TBBPA. Results showed that TBBPA significantly increased intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and the ratio of oxidized/reduced glutathione (GSSG/GSH) dose-dependently. TBBPA also decreased the cell mitochondrial membrane potential (MMP), caused the release of cytochrome C (Cyt C) to cytoplasm and promoted the expression of caspase-9 and caspase-3, and finally increased the level of apoptosis. The ROS inhibitor N-acetyl-L-cysteine (NAC) relieved the oxidative stress responses, and prevented the decrease of MMP and increase of apoptosis. In addition, TBBPA promoted the expression of antioxidant genes related to Nrf2, such as quinone oxidoreductase 1 (NQO1), catalase (CAT), and heme oxygenase 1 (HO-1). Oxidative stress initiated by TBBPA, activated mitochondrial apoptosis and Nrf2 pathway, and increased the degree of apoptosis in L02 cells.
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Affiliation(s)
- Yunchao Zhang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Xiaoli Wang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Chao Chen
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Jing An
- Institute for Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, PR China
| | - Yu Shang
- Institute for Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, PR China
| | - Hui Li
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China; Institute for Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, PR China.
| | - Hubin Xia
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Jun Yu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Chen Wang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Yongdi Liu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Shu Guo
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, Guangdong Province, 510655, PR China
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11
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Farmahin R, Gannon AM, Gagné R, Rowan-Carroll A, Kuo B, Williams A, Curran I, Yauk CL. Hepatic transcriptional dose-response analysis of male and female Fischer rats exposed to hexabromocyclododecane. Food Chem Toxicol 2018; 133:110262. [PMID: 30594549 DOI: 10.1016/j.fct.2018.12.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/13/2018] [Accepted: 12/20/2018] [Indexed: 12/14/2022]
Abstract
Hexabromocyclododecane (HBCD) is a brominated flame retardant found in the environment and human tissues. The toxicological effects of HBCD exposure are not clearly understood. We employed whole-genome RNA-sequencing on liver samples from male and female Fischer rats exposed to 0, 250, 1250, and 5000 mg technical mixture of HBCD/kg diet for 28 days to gain further insight into HBCD toxicity. HBCD altered 428 and 250 gene transcripts in males and females, respectively, which were involved in metabolism of xenobiotics, oxidative stress, immune response, metabolism of glucose and lipids, circadian regulation, cell cycle, fibrotic activity, and hormonal balance. Signature analysis supported that HBCD operates through the constitutive androstane and pregnane X receptors. The median transcriptomic benchmark dose (BMD) for the lowest statistically significant pathway was within 1.5-fold of the BMD for increased liver weight, while the BMD for the lowest pathway with at least three modeled genes (minimum 5% of pathway) was similar to the lowest apical endpoint BMD. The results show how transcriptional analyses can inform mechanisms underlying chemical toxicity and the doses at which potentially adverse effects occur. This experiment is part of a larger study exploring the use of toxicogenomics and high-throughput screening for human health risk assessment.
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Affiliation(s)
- Reza Farmahin
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, K1A 0K9, Canada
| | - Anne Marie Gannon
- Regulatory Toxicology Research Division, Health Products and Food Branch, Health Canada, Ottawa, ON, K1A 0K9, Canada
| | - Rémi Gagné
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, K1A 0K9, Canada
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, K1A 0K9, Canada
| | - Byron Kuo
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, K1A 0K9, Canada
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, K1A 0K9, Canada
| | - Ivan Curran
- Regulatory Toxicology Research Division, Health Products and Food Branch, Health Canada, Ottawa, ON, K1A 0K9, Canada
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, K1A 0K9, Canada.
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12
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Beck KR, Sommer TJ, Schuster D, Odermatt A. Evaluation of tetrabromobisphenol A effects on human glucocorticoid and androgen receptors: A comparison of results from human- with yeast-based in vitro assays. Toxicology 2016; 370:70-77. [PMID: 27693315 PMCID: PMC6828555 DOI: 10.1016/j.tox.2016.09.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 09/23/2016] [Accepted: 09/27/2016] [Indexed: 01/23/2023]
Abstract
The incidence of immune-related diseases increased over the last years in industrialized countries, suggesting a contribution of environmental factors. Impaired glucocorticoid action has been associated with immune disorders. Thus, there is an increasing interest to identify chemicals disrupting glucocorticoid action. The widely used flame retardant tetrabromobisphenol A (TBBPA) was reported earlier to potently inhibit glucocorticoid receptor (GR) and moderately androgen receptor (AR) activity in yeast-based reporter gene assays. To further characterize possible GR disrupting effects of TBBPA, transactivation experiments using a human HEK-293 cell-based reporter gene assay and cell-free receptor binding experiments were performed in the present study. Both, transactivation and GR binding experiments failed to detect any activity of TBBPA on GR function. Molecular docking calculations supported this observation. Additionally, the current study could confirm the antiandrogenic activity of TBBPA seen in the yeast assay, although the effect was an order of magnitude less pronounced in the HEK-293 cell-based system. In conclusion, TBBPA does not directly affect GR function and, considering its rapid metabolism and low concentrations found in humans, it is unlikely to cause adverse effects by acting through AR. This study emphasizes the use of cell-free assays in combination with cell-based assays for the in vitro evaluation of endocrine disrupting chemicals.
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Affiliation(s)
- Katharina R Beck
- Swiss Center for Applied Human Toxicology and Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, Pharmacenter, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Tanja J Sommer
- Swiss Center for Applied Human Toxicology and Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, Pharmacenter, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Daniela Schuster
- Institute of Pharmacy/Pharmaceutical Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), Computer Aided Molecular Design Group, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Alex Odermatt
- Swiss Center for Applied Human Toxicology and Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, Pharmacenter, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland.
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13
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Anisuzzaman S, Whalen MM. Tetrabromobisphenol A and hexabromocyclododecane alter secretion of IL-1β from human immune cells. J Immunotoxicol 2016; 13:403-16. [PMID: 27297965 PMCID: PMC4910520 DOI: 10.3109/1547691x.2015.1111960] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 10/19/2015] [Indexed: 12/29/2022] Open
Abstract
Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD), flame retardant compounds used in epoxy resin circuit boards and upholstery, contaminate the environment and are found in human serum. Lymphocytes and monocytes are immune cells that, among other functions, secrete pro-inflammatory cytokines such as interleukin (IL)-1β, an important regulator of immune responsiveness and tissue growth and repair. Thus, if its levels are dysregulated, loss of proper immune function and increased invasiveness of tumors could ensue. This study examines whether exposures to varying concentrations (0.05-5.0 μM) of TBBPA and HBCD for 24 h, 48 h and 6 days interfere with the ability of immune cells to secrete IL-1β. The immune cell preparations examined were human natural killer (NK) cells, monocyte-depleted (MD) peripheral blood mononuclear cells (MD-PBMC) and PBMC. Both increased and decreased secretion of IL-1β from all three types of cell preparation were seen with TBBPA exposures and were dependent on concentration and length of exposure. TBBPA induced changes varied considerably from donor to donor. Exposure to HBCD from 0.5-5.0 μM caused increases in IL-1β secretion after all lengths of exposures in all cell preparations. The specific HBCD levels at which increases occurred varied among donors. Examinations of the signaling pathway(s) responsible for the elevated secretion of IL-1β after HBCD exposure were carried out in MD-PBMC cells. Results revealed that MAPK pathways (ERK1/2 and p38) appear to be the targets of HBCD that lead to increased IL-1β secretion from immune cells.
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Affiliation(s)
- Sharif Anisuzzaman
- a Department of Chemistry , Tennessee State University , Nashville , TN , USA
| | - Margaret M Whalen
- a Department of Chemistry , Tennessee State University , Nashville , TN , USA
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14
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An J, Guo P, Shang Y, Zhong Y, Zhang X, Yu Y, Yu Z. The "adaptive responses" of low concentrations of HBCD in L02 cells and the underlying molecular mechanisms. CHEMOSPHERE 2016; 145:68-76. [PMID: 26688241 DOI: 10.1016/j.chemosphere.2015.11.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 06/05/2023]
Abstract
This study aimed to investigate the "adaptive responses" of hexabromocyclododecanes (HBCD) at environmentally relevant concentrations in human hepatocytes L02. L02 cells were pre-treated with low concentrations of HBCD (10(-13)-10(-11) M), followed by treatment with high concentrations of HBCD, α-hexachlorocyclohexane (α-HCH), polychlorinated biphenyls (PCBs), or polybrominated diphenyl ether-47 (BDE47). The results showed that the pre-treatment with low concentrations of HBCD induced "adaptive responses" to high concentrations of HBCD/α-HCH exposure (but not to PCBs and BDE47), as evidenced by attenuation of survival inhibition, reactive oxygen species (ROS) over-production, and deoxyribonucleic acid (DNA) damage induction. The "adaptive responses" induced by low concentrations of HBCD, which depended on the activation of the phosphatidylinositide 3-kinase/protein kinase B (PI3K/Akt) pathway, reduced the phosphorylation of adenosine monophosphate-activated kinase (AMPK) and enhanced the phosphorylation of p38 mitogen-activated protein kinases (p38 MAPK). The observations were further confirmed by the experiments with inhibitors. Moreover, the evaluation on the changes of metabolic enzymes revealed that HBCD and α-HCH shared a similar pattern of cytochrome P450 induction (CYP2B6), which was different from those of PCBs and BDE47 (CYP1A1 and CYP2B6). These results indicated that low concentrations of HBCD could induce "adaptive responses" to the subsequent treatment with high concentrations of HBCD/α-HCH in L02 cells, which was associated with the PI3K/Akt pathway, and AMPK and p38 MAPK signaling. The "adaptive responses" seemed to be dependent on the types of chemicals in terms of the metabolic patterns and chemical structures.
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Affiliation(s)
- Jing An
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China.
| | - Panpan Guo
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Yu Shang
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Yufang Zhong
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Xinyu Zhang
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Yingxin Yu
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Zhiqiang Yu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China
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15
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Almughamsi H, Whalen MM. Hexabromocyclododecane and tetrabromobisphenol A alter secretion of interferon gamma (IFN-γ) from human immune cells. Arch Toxicol 2015; 90:1695-707. [PMID: 26302867 DOI: 10.1007/s00204-015-1586-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/13/2015] [Indexed: 10/23/2022]
Abstract
Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) are brominated flame-retardant compounds used in a variety of applications including insulation, upholstery, and epoxy resin circuit boards. Interferon gamma (IFN-γ) is an inflammatory cytokine produced by activated T and NK cells that regulates immune responsiveness. HBCD and TBBPA are found in human blood, and previous studies have shown that they alter the ability of human natural killer (NK) lymphocytes to destroy tumor cells. This study examines whether HBCD and TBBPA affect the secretion of IFN-γ from increasingly complex preparations of human immune cells-purified NK cells, monocyte-depleted (MD) peripheral blood mononuclear cells (PBMCs), and PBMCs. Both HBCD and TBBPA were tested at concentrations ranging from 0.05 to 5 µM. HBCD generally caused increases in IFN-γ secretion after 24-h, 48-h, and 6-day exposures in each of the different cell preparations. The specific concentration of HBCD that caused increases as well as the magnitude of the increase varied from donor to donor. In contrast, TBBPA tended to decrease secretion of IFN-γ from NK cells, MD-PBMCs, and PBMCs. Thus, exposure to these compounds may potentially disrupt the immune regulation mediated by IFN-γ. Signaling pathways that have the capacity to regulate IFN-γ production (nuclear factor kappa B (NF-κB), p44/42, p38, JNK) were examined for their role in the HBCD-induced increases in IFN-γ. Results showed that the p44/42 (ERK1/2) MAPK pathway appears to be important in HBCD-induced increases in IFN-γ secretion from human immune cells.
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Affiliation(s)
- Haifa Almughamsi
- Department of Chemistry, Tennessee State University, 3500 John A. Merritt Blvd., Nashville, TN, 37209, USA
| | - Margaret M Whalen
- Department of Chemistry, Tennessee State University, 3500 John A. Merritt Blvd., Nashville, TN, 37209, USA.
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16
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Rana K, Whalen M. Activation of protein kinase C and protein kinase D in human natural killer cells: effects of tributyltin, dibutyltin, and tetrabromobisphenol A. Toxicol Mech Methods 2015; 25:680-8. [PMID: 26228090 DOI: 10.3109/15376516.2015.1070226] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Up to now, the ability of target cells to activate protein kinase C (PKC) and protein kinase D (PKD) (which is often a downstream target of PKC) has not been examined in natural killer (NK) lymphocytes. Here we examined whether exposure of human NK cells to lysis sensitive tumor cells activated PKC and PKD. The results of these studies show for the first time that activation of PKC and PKD occurs in response to target cell binding to NK cells. Exposure of NK cells to K562 tumor cells for 10 and 30 min increased phosphorylation/activation of both PKC and PKD by roughly 2-fold. Butyltins (tributyltin (TBT), dibutyltin (DBT)) and brominated compounds (tetrabromobisphenol A (TBBPA)) are environmental contaminants that are found in human blood. Exposures of NK cells to TBT, DBT, or TBBPA decrease NK cell lytic function in part by activating the mitogen-activated protein kinases (MAPKs) that are part of the NK lytic pathway. We established that PKC and PKD are part of the lytic pathway upstream of MAPKs and thus we investigated whether DBT, TBT, and TBBPA exposures activated PKC and PKD. TBT-activated PKC by 2-3-folds at 10 min at concentrations ranging from 50 to 300 nM while DBT caused a 1.3-fold activation at 2.5 µM at 10 min. Both TBT and DBT caused an approximately 2-fold increase in phosphorylation/activation of PKC. Exposures to TBBPA caused no statistically significant changes in either PKC or PKD activation.
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Affiliation(s)
| | - Margaret Whalen
- b Department of Chemistry , Tennessee State University , Nashville , TN , USA
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17
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Akiyama E, Kakutani H, Nakao T, Motomura Y, Takano Y, Sorakubo R, Mizuno A, Aozasa O, Tachibana K, Doi T, Ohta S. Facilitation of adipocyte differentiation of 3T3-L1 cells by debrominated tetrabromobisphenol A compounds detected in Japanese breast milk. ENVIRONMENTAL RESEARCH 2015; 140:157-164. [PMID: 25863188 DOI: 10.1016/j.envres.2015.03.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 03/05/2015] [Accepted: 03/30/2015] [Indexed: 06/04/2023]
Abstract
Tetrabromobisphenol A (TeBBPA) is widely used type of brominated flame retardant. In this study, we newly synthesized materials for the debrominated congeners, 2,2',6-tribromobisphenol A (TriBBPA), 2,2'-dibromobisphenol A (2,2'-DiBBPA), 2,6-dibromobisphenol A (2,6-DiBBPA), and 2-monobromobisphenol A (MoBBPA) and evaluated the actual extent of contamination with bisphenol A (BPA), TeBBPA and debrominated congeners in Japanese breast milk samples. TriBBPA was detected at higher levels than that of TeBBPA, while DiBBPA and MoBBPA were detected at lower levels than that of TeBBPA. This observation suggested that humans are exposed to debrominated congeners, which might cause adverse effects. Contamination of the congeners in breast milk was concern about risk infant health, having vulnerable defense system. As pilot study by in vitro experiment, we assessed the toxic potency of debrominated congeners by studying their effect on adipocyte differentiation in 3T3-L1 cells. We observed 2,6-DiBBPA, TriBBPA and TeBBPA elevated the lipid accumulation and adipocyte-specific protein 2 expression in a manner dependent on the number of substituted bromines. Moreover, PPARγ transcriptional activities increased in a dose-dependent manner in the presence of 2,6-DiBBPA and TriBBPA as well as TeBBPA. Our study clarified that TeBBPA and its debrominated congeners accumulated in breast milk and the debrominated congeners promoted adipocyte differentiation, showing that a comprehensive evaluation of the influences of these compounds including the debrominated congeners of TeBBPA on health in infants is necessary.
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Affiliation(s)
- Ema Akiyama
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
| | - Hideki Kakutani
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
| | - Teruyuki Nakao
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
| | - Yuka Motomura
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
| | - Yuki Takano
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
| | - Ryota Sorakubo
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
| | - Ayami Mizuno
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
| | - Osamu Aozasa
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Keisuke Tachibana
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan; Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takefumi Doi
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan; Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Souichi Ohta
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan.
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