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Låg M, Øvrevik J, Totlandsdal AI, Lilleaas EM, Thormodsæter A, Holme JA, Schwarze PE, Refsnes M. Air pollution-related metals induce differential cytokine responses in bronchial epithelial cells. Toxicol In Vitro 2016; 36:53-65. [PMID: 27427241 DOI: 10.1016/j.tiv.2016.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/21/2016] [Accepted: 07/13/2016] [Indexed: 12/22/2022]
Abstract
Different transition metals have been shown to induce inflammatory responses in lung. We have compared eight different metal ions with regard to cytokine responses, cytotoxicity and signalling mechanisms in a human lung epithelial cell model (BEAS-2B). Among the metal ions tested, there were large differences with respect to pro-inflammatory potential. Exposure to Cd(2+), Zn(2+) and As(3+) induced CXCL8 and IL-6 release at concentrations below 100μM, and Mn(2+) and Ni(2+) at concentrations above 200μM. In contrast, VO4(3-), Cu(2+) and Fe(2+) did not induce any significant increase of these cytokines. An expression array of 20 inflammatory relevant genes also showed a marked up-regulation of CXCL10, IL-10, IL-13 and CSF2 by one or more of the metal ions. The most potent metals, Cd(2+), Zn(2+) and As(3+) induced highest levels of oxidative activity, and ROS appeared to be central in their CXCL8 and IL-6 responses. Activation of the MAPK p38 seemed to be a critical mediator. However, the NF-κB pathway appeared predominately to be involved only in Zn(2+)- and As(3+)-induced CXCL8 and IL-6 responses. Thus, the most potent metals Cd(2+), Zn(2+) and As(3+) seemed to induce a similar pattern for the cytokine responses, and with some exceptions, via similar signalling mechanisms.
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Affiliation(s)
- M Låg
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway.
| | - J Øvrevik
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
| | - A I Totlandsdal
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
| | - E M Lilleaas
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
| | - A Thormodsæter
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
| | - J A Holme
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
| | - P E Schwarze
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
| | - M Refsnes
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
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Bach N, Bølling AK, Brinchmann BC, Totlandsdal AI, Skuland T, Holme JA, Låg M, Schwarze PE, Øvrevik J. Cytokine responses induced by diesel exhaust particles are suppressed by PAR-2 silencing and antioxidant treatment, and driven by polar and non-polar soluble constituents. Toxicol Lett 2015; 238:72-82. [PMID: 26160521 DOI: 10.1016/j.toxlet.2015.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 07/01/2015] [Accepted: 07/02/2015] [Indexed: 12/14/2022]
Abstract
Adsorbed soluble organics seem to be the main drivers of inflammatory responses induced by diesel exhaust particles (DEP). The specific compounds contributing to this process and the cellular mechanisms behind DEP-induced inflammation are not well known. We have assessed pro-inflammatory effects of DEP and various soluble DEP fractions, in human bronchial epithelial cells (BEAS-2B). DEP increased the expression of interleukin (IL)-6 and CXCL8. Silencing of the aryl hydrocarbon receptor (AhR) by siRNA or pretreatment with AhR-antagonists did not attenuate DEP-induced IL-6 and CXCL8 responses. However, the halogenated aromatic hydrocarbon (HAH)-selective AhR antagonist CH223191 caused a considerable reduction in DEP-induced CYP1A1 expression indicating that this response may be due to dioxin or dioxin-like constituents in DEP. Knock-down of protease activated receptor (PAR)-2 attenuated IL-6 responses without affecting CXCL8. Antioxidants did not affect IL-6 expression after 4h DEP-exposure and only partly reduced CXCL8 expression. However, after 24h exposure antioxidant treatment partly suppressed IL-6 protein release and completely blocked CXCL8 release. Furthermore, a heptane-soluble (non-polar) extract of DEP induced both IL-6 and CXCL8 release, whereas a PBS-soluble (highly polar) extract induced only IL-6. Thus, pro-inflammatory responses in DEP-exposed epithelial cells appear to be the result of both reactive oxygen species and receptor signaling, mediated through combinatorial effects between both non-polar and polar constituents adhered to the particle surface.
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Affiliation(s)
- Nicolai Bach
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway; Department of Biology, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
| | - Anette Kocbach Bølling
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway
| | - Bendik C Brinchmann
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway
| | - Annike I Totlandsdal
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway
| | - Tonje Skuland
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway
| | - Jørn A Holme
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway
| | - Marit Låg
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway
| | - Per E Schwarze
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway
| | - Johan Øvrevik
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Norway.
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Totlandsdal AI, Låg M, Lilleaas E, Cassee F, Schwarze P. Differential proinflammatory responses induced by diesel exhaust particles with contrasting PAH and metal content. Environ Toxicol 2015; 30:188-96. [PMID: 23900936 DOI: 10.1002/tox.21884] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 05/22/2013] [Accepted: 05/22/2013] [Indexed: 05/22/2023]
Abstract
Exposure to diesel engine exhaust particles (DEPs), representing a complex and variable mixture of components, has been linked with cellular production and release of several types of mediators related to pulmonary inflammation. A key challenge is to identify the specific components, which may be responsible for these effects. The aim of this study was to compare the proinflammatory potential of two DEP-samples with contrasting contents of polycyclic aromatic hydrocarbons (PAHs) and metals. The DEP-samples were compared with respect to their ability to induce cytotoxicity, expression and release of proinflammatory mediators (IL-6, IL-8), activation of mitogen-activated protein kinases (MAPKs) and expression of CYP1A1 and heme oxygenase-1 (HO-1) in human bronchial epithelial (BEAS-2B) cells. In addition, dithiothreitol and ascorbic acid assays were performed in order to examine the oxidative potential of the PM samples. The DEP-sample with the highest PAH and lowest metal content was more potent with respect to cytotoxicity and expression and release of proinflammatory mediators, CYP1A1 and HO-1 expression and MAPK activation, than the DEP-sample with lower PAH and higher metal content. The DEP-sample with the highest PAH and lowest metal content also possessed a greater oxidative potential. The present results indicate that the content of organic components may be determinant for the proinflammatory effects of DEP. The findings underscore the importance of considering the chemical composition of particulate matter-emissions, when evaluating the potential health impact and implementation of air pollution regulations.
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Affiliation(s)
- Annike I Totlandsdal
- Division of Environmental Medicine, Department of Air Pollution and Noise, Norwegian Institute of Public Health, Oslo, Norway
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Totlandsdal AI, Øvrevik J, Cochran RE, Herseth JI, Bølling AK, Låg M, Schwarze P, Lilleaas E, Holme JA, Kubátová A. The occurrence of polycyclic aromatic hydrocarbons and their derivatives and the proinflammatory potential of fractionated extracts of diesel exhaust and wood smoke particles. J Environ Sci Health A Tox Hazard Subst Environ Eng 2014; 49:383-96. [PMID: 24345236 DOI: 10.1080/10934529.2014.854586] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Exposure to combustion emissions, including diesel engine exhaust and wood smoke particles (DEPs and WSPs), has been associated with inflammatory responses. To investigate the possible role of polycyclic aromatic hydrocarbons (PAHs) and PAH-derivatives, the DEPs and WSPs methanol extracts were fractionated by solid phase extraction (SPE), and the fractions were analyzed for more than ∼120 compounds. The pro-inflammatory effects of the fractionated extracts were characterized by exposure of bronchial epithelial lung cells (BEAS-2B). Both native DEPs and WSPs caused a concentration-dependent increase in IL-6 and IL-8 release and cytotoxicity. This is consistent with the finding of a rather similar total content of PAHs and PAH-derivatives. Yet, the samples differed in specific components, suggesting that different species contribute to the toxicological response in these two types of particles. The majority of the IL-6 release and cytotoxicity was induced upon exposure to the most polar (methanol) SPE fraction of extracts from both samples. In these fractions hydroxy-PAHs, carboxy-PAHs were observed along with nitro-amino-PAHs in DEP. However, the biological effects induced by the polar fractions could not be attributed only to the occurrence of PAH-derivatives. The present findings indicate a need for further characterization of organic extracts, beyond an extensive analysis of commonly suspected PAH and PAH-derivatives. Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Environmental Science and Health, Part A, to view the supplemental file.
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Affiliation(s)
- Annike I Totlandsdal
- a Department of Air Pollution and Noise, Division of Environmental Medicine , Norwegian Institute of Public Health , Oslo , Norway
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Gerlofs-Nijland ME, Totlandsdal AI, Tzamkiozis T, Leseman DLAC, Samaras Z, Låg M, Schwarze P, Ntziachristos L, Cassee FR. Cell toxicity and oxidative potential of engine exhaust particles: impact of using particulate filter or biodiesel fuel blend. Environ Sci Technol 2013; 47:5931-8. [PMID: 23597117 DOI: 10.1021/es305330y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The link between emissions of vehicular particulate matter (PM) and adverse health effects is well established. However, the influence of new emission control technologies and fuel types on both PM emissions and health effects has been less well investigated. We examined the health impact of PM emissions from two vehicles equipped with or without a diesel particulate filter (DPF). Both vehicles were powered either with diesel (B0) or a 50% v/v biodiesel blend (B50). The DPF effectively decreased PM mass emissions (∼85%), whereas the fuel B50 without DPF lead to less reduction (∼50%). The hazard of PM per unit distance driven was decreased for the DPF-equipped vehicle as indicated by a reduced cytotoxicity, oxidative, and pro-inflammatory potential. This was not evident and even led to an increase when the hazard was expressed on a per unit of mass basis. In general, the PM oxidative potential was similar or reduced for the B50 compared to the B0 powered vehicle. However, the use of B50 resulted in increased cytotoxicity and IL-6 release in BEAS-2B cells irrespective of the expression metric. This study shows that PM mass reduction achieved by the use of B50 will not necessarily decrease the hazard of engine emissions, while the application of a DPF has a beneficial effect on both PM mass emission and PM hazard.
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Affiliation(s)
- Miriam E Gerlofs-Nijland
- Centre for Environmental Health, National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands.
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Gerlofs-Nijland ME, Totlandsdal AI, Kilinç E, Boere AJF, Fokkens PHB, Leseman DLAC, Sioutas C, Schwarze PE, Spronk HM, Hadoke PWF, Miller MR, Cassee FR. Pulmonary and cardiovascular effects of traffic-related particulate matter: 4-week exposure of rats to roadside and diesel engine exhaust particles. Inhal Toxicol 2011; 22:1162-73. [PMID: 21126152 DOI: 10.3109/08958378.2010.531062] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Traffic-related particulate matter (PM) may play an important role in the development of adverse health effects, as documented extensively in acute toxicity studies. However, rather little is known about the impacts of prolonged exposure to PM. We hypothesized that long-term exposure to PM from traffic adversely affects the pulmonary and cardiovascular system through exacerbation of an inflammatory response. To examine this hypothesis, Fisher F344 rats, with a mild pulmonary inflammation at the onset of exposure, were exposed for 4 weeks, 5 days/week for 6 h a day to: (a) diluted diesel engine exhaust (PM(DEE)), or: (b) near roadside PM (PM(2.5)). Ultrafine particulates, which are largely present in diesel soot, may enter the systemic circulation and directly or indirectly trigger cardiovascular effects. Hence, we assessed the effects of traffic-related PM on pulmonary inflammation and activity of procoagulants, vascular function in arteries, and cytokine levels in the heart 24 h after termination of the exposures. No major adverse health effects of prolonged exposure to traffic-related PM were detected. However, some systemic effects due to PM(DEE) exposure occurred including decreased numbers of white blood cells and reduced von Willebrand factor protein in the circulation. In addition, lung tissue factor activity is reduced in conjunction with reduced lung tissue thrombin generation. To what extent these alterations contribute to thrombotic effects and vascular diseases remains to be established. In conclusion, prolonged exposure to traffic-related PM in healthy animals may not be detrimental due to various biological adaptive response mechanisms.
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Affiliation(s)
- Miriam E Gerlofs-Nijland
- Environment and Safety Division, Centre for Environmental Health, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
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Totlandsdal AI, Cassee FR, Schwarze P, Refsnes M, Låg M. Diesel exhaust particles induce CYP1A1 and pro-inflammatory responses via differential pathways in human bronchial epithelial cells. Part Fibre Toxicol 2010; 7:41. [PMID: 21162728 PMCID: PMC3012014 DOI: 10.1186/1743-8977-7-41] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 12/16/2010] [Indexed: 12/27/2022] Open
Abstract
Background Exposure to diesel engine exhaust particles (DEPs) has been associated with several adverse health outcomes in which inflammation seems to play a key role. DEPs contain a range of different inorganic and organic compounds, including polycyclic aromatic hydrocarbons (PAHs). During the metabolic activation of PAHs, CYP1A1 enzymes are known to play a critical role. In the present study we investigated the potential of a characterised sample of DEPs to induce cytotoxicity, to influence the expression of CYP1A1 and inflammation-related genes, and to activate intracellular signalling pathways, in human bronchial epithelial cells. We specifically investigated to what extent DEP-induced expression of interleukin (IL)-6, IL-8 and cyclooxygenase (COX)-2 was regulated differentially from DEP-induced expression of CYP1A1. Results The cytotoxicity of the DEPs was characterised by a marked time- and concentration-dependent increase in necrotic cells at 4 h and above 200 μg/ml (~ 30 μg/cm2). DEP-induced DNA-damage was only apparent at high concentrations (≥ 200 μg/ml). IL-6, IL-8 and COX-2 were the three most up-regulated genes by the DEPs in a screening of 20 selected inflammation-related genes. DEP-induced expression of CYP1A1 was detected at very low concentrations (0.025 μg/ml), compared to the expression of IL-6, IL-8 and COX-2 (50-100 μg/ml). A CYP1A1 inhibitor (α-naphthoflavone), nearly abolished the DEP-induced expression of IL-8 and COX-2. Of the investigated mitogen-activated protein kinases (MAPKs), the DEPs induced activation of p38. A p38 inhibitor (SB202190) strongly reduced DEP-induced expression of IL-6, IL-8 and COX-2, but only moderately affected the expression of CYP1A1. The DEPs also activated the nuclear factor-κB (NF-κB) pathway, and suppression by siRNA tended to reduce the DEP-induced expression of IL-8 and COX-2, but not CYP1A1. Conclusion The present study indicates that DEPs induce both CYP1A1 and pro-inflammatory responses in vitro, but via differential intracellular pathways. DEP-induced pro-inflammatory responses seem to occur via activation of NF-κB and p38 and are facilitated by CYP1A1. However, the DEP-induced CYP1A1 response does not seem to involve NF-κB and p38 activation. Notably, the present study also indicates that expression of CYP1A1 may represent a particular sensitive biomarker of DEP-exposure.
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Affiliation(s)
- Annike I Totlandsdal
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Oslo, Norway.
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Totlandsdal AI, Refsnes M, Låg M. Mechanisms involved in ultrafine carbon black-induced release of IL-6 from primary rat epithelial lung cells. Toxicol In Vitro 2010; 24:10-20. [DOI: 10.1016/j.tiv.2009.09.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 06/26/2009] [Accepted: 09/21/2009] [Indexed: 01/15/2023]
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Totlandsdal AI, Refsnes M, Skomedal T, Osnes JB, Schwarze PE, Låg M. Particle-Induced Cytokine Responses in Cardiac Cell Cultures—the Effect of Particles versus Soluble Mediators Released by Particle-Exposed Lung Cells. Toxicol Sci 2008; 106:233-41. [DOI: 10.1093/toxsci/kfn162] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Totlandsdal AI, Skomedal T, Låg M, Osnes JB, Refsnes M. Pro-inflammatory potential of ultrafine particles in mono- and co-cultures of primary cardiac cells. Toxicology 2008; 247:23-32. [DOI: 10.1016/j.tox.2008.01.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 01/24/2008] [Accepted: 01/27/2008] [Indexed: 11/16/2022]
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Totlandsdal AI, Dybing E, Schwarze PE. From science to policy--when are scientific results certain enough? Toxicol Sci 2006; 94:256-60. [PMID: 16945987 DOI: 10.1093/toxsci/kfl095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The amount of scientific findings linking air pollution with adverse health effects is continuously growing and indicates a need for action to improve air quality. On 21 September 2005, the European Commission published a new draft directive on air quality, as part of the Thematic Strategy on air pollution. This is a long-term plan on how to reduce air pollution in the European Union in the next 15 years. Immediately after its release, the Commission received criticism for not going far enough from various instances, such as research institutions and nongovernmental organizations concerned with health and environmental effects of air pollution. One policy argument for not taking full measures was the argument of scientific uncertainty. In light of this air quality strategy and the corresponding criticism which ensued, the present article discusses how the ambiguity of scientific uncertainty may contribute to impeding the process of translating scientific findings into concrete policy options. As complete certainty is likely to never be achieved, the question arises whether it is possible to determine and agree on clear and applicable definitions of certain levels of scientific certainty. The case referred to in this paper clearly demonstrates a situation with discordant views on the uncertainty of scientific findings. More discussion on how to define scientific uncertainty and how to deal with it would be beneficial for both the scientific and the political communities. Finally, it is important to recognize that scientific evidence is not the only driver influencing policy decisions.
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Affiliation(s)
- Annike I Totlandsdal
- Division of Environmental Medicine, Norwegian Institute of Public Health, NO-0403 Oslo, Norway.
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