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Michaeloudes C, Abubakar-Waziri H, Lakhdar R, Raby K, Dixey P, Adcock IM, Mumby S, Bhavsar PK, Chung KF. Molecular mechanisms of oxidative stress in asthma. Mol Aspects Med 2021; 85:101026. [PMID: 34625291 DOI: 10.1016/j.mam.2021.101026] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/15/2021] [Indexed: 01/18/2023]
Abstract
The lungs are exposed to reactive oxygen species oxygen (ROS) produced as a result of inhalation of oxygen, as well as smoke and other air pollutants. Cell metabolism and the NADPH oxidases (Nox) generate low levels of intracellular ROS that act as signal transduction mediators by inducing oxidative modifications of histones, enzymes and transcription factors. Redox signalling is also regulated by localised production and sensing of ROS in mitochondria, the endoplasmic reticulum (ER) and inside the nucleus. Intracellular ROS are maintained at low levels through the action of a battery of enzymatic and non-enzymatic antioxidants. Asthma is a heterogeneous airway inflammatory disease with different immune endotypes; these include atopic or non-atopic Th2 type immune response associated with eosinophilia, or a non-Th2 response associated with neutrophilia. Airway remodelling and hyperresponsiveness accompany the inflammatory response in asthma. Over-production of ROS resulting from infiltrating immune cells, particularly eosinophils and neutrophils, and a concomitant impairment of antioxidant responses lead to development of oxidative stress in asthma. Oxidative stress is augmented in severe asthma and during exacerbations, as well as by air pollution and obesity, and causes oxidative damage of tissues promoting airway inflammation and hyperresponsiveness. Furthermore, deregulated Nox activity, mitochondrial dysfunction, ER stress and/or oxidative DNA damage, resulting from exposure to irritants, inflammatory mediators or obesity, may lead to redox-dependent changes in cell signalling. ROS play a central role in airway epithelium-mediated sensing, development of innate and adaptive immune responses, and airway remodelling and hyperresponsiveness. Nonetheless, antioxidant compounds have proven clinically ineffective as therapeutic agents for asthma, partly due to issues with stability and in vivo metabolism of these compounds. The compartmentalised nature of ROS production and sensing, and the role of ROS in homeostatic responses and in the action of corticosteroids and β2-adrenergic receptor agonists, adds another layer of complexity to antioxidant therapy development. Nox inhibitors and mitochondrial-targeted antioxidants are in clinical development for a number of diseases but they have not yet been investigated in asthma. A better understanding of the complex role of ROS in the pathogenesis of asthma will highlight new opportunities for more targeted and effective redox therapies.
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Affiliation(s)
- Charalambos Michaeloudes
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom.
| | - Hisham Abubakar-Waziri
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Ramzi Lakhdar
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Katie Raby
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Piers Dixey
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Ian M Adcock
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Sharon Mumby
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Pankaj K Bhavsar
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Kian Fan Chung
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom; Royal Brompton & Harefield NHS Trust, London, UK
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Engin AB. Combined Toxicity of Metal Nanoparticles: Comparison of Individual and Mixture Particles Effect. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1275:165-193. [PMID: 33539016 DOI: 10.1007/978-3-030-49844-3_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Toxicity of metal nanoparticles (NPs) are closely associated with increasing intracellular reactive oxygen species (ROS) and the levels of pro-inflammatory mediators. However, NP interactions and surface complexation reactions alter the original toxicity of individual NPs. To date, toxicity studies on NPs have mostly been focused on individual NPs instead of the combination of several species. It is expected that the amount of industrial and highway-acquired NPs released into the environment will further increase in the near future. This raises the possibility that various types of NPs could be found in the same medium, thereby, the adverse effects of each NP either could be potentiated, inhibited or remain unaffected by the presence of the other NPs. After uptake of NPs into the human body from various routes, protein kinases pathways mediate their toxicities. In this context, family of mitogen-activated protein kinases (MAPKs) is mostly efficient. Despite each NP activates almost the same metabolic pathways, the toxicity induced by a single type of NP is different than the case of co-exposure to the combined NPs. The scantiness of toxicological data on NPs combinations displays difficulties to determine, if there is any risk associated with exposure to combined nanomaterials. Currently, in addition to mathematical analysis (Response surface methodology; RSM), the quantitative-structure-activity relationship (QSAR) is used to estimate the toxicity of various metal oxide NPs based on their physicochemical properties and levels applied. In this chapter, it is discussed whether the coexistence of multiple metal NPs alter the original toxicity of individual NP. Additionally, in the part of "Toxicity of diesel emission/exhaust particles (DEP)", the known individual toxicity of metal NPs within the DEP is compared with the data regarding toxicity of total DEP mixture.
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Affiliation(s)
- Ayse Basak Engin
- Department of Toxicology, Faculty of Pharmacy, Gazi University, Ankara, Turkey.
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Yan Z, Jin Y, An Z, Liu Y, Samet JM, Wu W. Inflammatory cell signaling following exposures to particulate matter and ozone. Biochim Biophys Acta Gen Subj 2016; 1860:2826-34. [PMID: 27015762 DOI: 10.1016/j.bbagen.2016.03.030] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 01/12/2023]
Abstract
BACKGROUND Particulate matter (PM) and ozone (O3) are two major ambient air pollutants. Epidemiological and toxicological studies have demonstrated exposure to these pollutants is associated with a variety of adverse health effects, including cardiovascular and respiratory disease, in which inflammation is believed to be a common and essential factor. SCOPE OF REVIEW This review mainly focuses on major inflammatory cell signaling pathways triggered by exposure to PM and O3. The receptors covered in this review include the EGF receptor, toll like receptor, and NOD-like receptor. Intracellular signaling protein kinases depicted in this review are phosphatidylinositol 3-kinase and mitogen-activated protein kinases. Activation of antioxidant and inflammatory transcription factors such as NrF2 and NFκB induced by PM and O3 is also discussed. MAJOR CONCLUSIONS Exposure to PM or O3 can activate cellular signaling networks including membrane receptors, intracellular kinases and phosphatases, and transcription factors that regulate inflammatory responses. While PM-induced cell signaling is associated with resultant ROS, O3-induced cell signaling implicates phosphates. Notably, the cellular signaling induced by PM and O3 exposure varies with cell type and physiochemical properties of these pollutants. GENERAL SIGNIFICANCE Cellular signaling plays a critical role in the regulation of inflammatory pathogenesis. Elucidation of cellular signaling pathways initiated by PM or O3 cannot only help to uncover the mechanisms of air pollutant toxicity but also provide clues for development of interventional measures against air pollution-induced disorders. This article is part of a Special Issue entitled Air Pollution, edited by Wenjun Ding, Andrew J. Ghio and Weidong Wu.
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Affiliation(s)
- Zhen Yan
- College of Public Health, Zhengzhou University, Zhengzhou, Henan Province 450001, PR China
| | - Yuefei Jin
- College of Public Health, Zhengzhou University, Zhengzhou, Henan Province 450001, PR China
| | - Zhen An
- School of Public Health, Xinxiang Medical University, Xinxiang, Henan Province 453003, PR China; Xinxiang Key Laboratory of Environmental Effects and Intervention, Xinxiang Medical University, Xinxiang, Henan Province 453003, PR China
| | - Yingying Liu
- School of Public Health, Xinxiang Medical University, Xinxiang, Henan Province 453003, PR China; Xinxiang Key Laboratory of Environmental Effects and Intervention, Xinxiang Medical University, Xinxiang, Henan Province 453003, PR China
| | - James M Samet
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Chapel Hill, NC 27599, USA
| | - Weidong Wu
- School of Public Health, Xinxiang Medical University, Xinxiang, Henan Province 453003, PR China; Xinxiang Key Laboratory of Environmental Effects and Intervention, Xinxiang Medical University, Xinxiang, Henan Province 453003, PR China; Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, Xinxiang Medical University, Xinxiang, Henan Province 453003, PR China.
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Wages PA, Lavrich KS, Zhang Z, Cheng WY, Corteselli E, Gold A, Bromberg P, Simmons SO, Samet JM. Protein Sulfenylation: A Novel Readout of Environmental Oxidant Stress. Chem Res Toxicol 2015; 28:2411-8. [PMID: 26605980 DOI: 10.1021/acs.chemrestox.5b00424] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Oxidative stress is a commonly cited mechanism of toxicity of environmental agents. Ubiquitous environmental chemicals such as the diesel exhaust component 1,2-naphthoquinone (1,2-NQ) induce oxidative stress by redox cycling, which generates hydrogen peroxide (H2O2). Cysteinyl thiolate residues on regulatory proteins are subjected to oxidative modification by H2O2 in physiological contexts and are also toxicological targets of oxidant stress induced by environmental contaminants. We investigated whether exposure to environmentally relevant concentrations of 1,2-NQ can induce H2O2-dependent oxidation of cysteinyl thiols in regulatory proteins as a readout of oxidant stress in human airway epithelial cells. BEAS-2B cells were exposed to 0-1000 μM 1,2-NQ for 0-30 min, and levels of H2O2 were measured by ratiometric spectrofluorometry of HyPer. H2O2-dependent protein sulfenylation was measured using immunohistochemistry, immunoblotting, and isotopic mass spectrometry. Catalase overexpression was used to investigate the relationship between H2O2 generation and protein sulfenylation in cells exposed to 1,2-NQ. Multiple experimental approaches showed that exposure to 1,2-NQ at concentrations as low as 3 μM induces H2O2-dependent protein sulfenylation in BEAS-2B cells. Moreover, the time of onset and duration of 1,2-NQ-induced sulfenylation of the regulatory proteins GAPDH and PTP1B showed significant differences. Oxidative modification of regulatory cysteinyl thiols in human lung cells exposed to relevant concentrations of an ambient air contaminant represents a novel marker of oxidative environmental stress.
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Affiliation(s)
- Phillip A Wages
- Curriculum in Toxicology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7310, United States
| | - Katelyn S Lavrich
- Curriculum in Toxicology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7310, United States
| | - Zhenfa Zhang
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7400, United States
| | - Wan-Yun Cheng
- Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States
| | - Elizabeth Corteselli
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7400, United States
| | - Avram Gold
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7400, United States
| | - Philip Bromberg
- Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7310, United States
| | - Steven O Simmons
- National Center for Computational Toxicology, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States
| | - James M Samet
- Curriculum in Toxicology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7310, United States.,Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency , Chapel Hill, North Carolina 27711, United States
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Wu W, Wages PA, Devlin RB, Diaz-Sanchez D, Peden DB, Samet JM. SRC-mediated EGF receptor activation regulates ozone-induced interleukin 8 expression in human bronchial epithelial cells. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:231-236. [PMID: 25303742 PMCID: PMC4348738 DOI: 10.1289/ehp.1307379] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/07/2014] [Indexed: 05/29/2023]
Abstract
BACKGROUND Human exposure to ozone (O3) results in pulmonary function decrements and airway inflammation. The mechanisms underlying these adverse effects remain unclear. Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of lung inflammation. OBJECTIVE We examined the role of EGFR activation in O3-induced expression of the chemokine interleukin 8 (IL-8) in human bronchial epithelial cells (HBEC). METHODS We detected phosphorylated EGFR using immunoblotting. EGFR dimerization was examined through cross-linking reaction and immunoblotting, and levels of IL-8 protein were measured using ELISA. RESULTS Exposure to O3 (0.25-1.0 ppm) induced rapid and marked increase in EGFR phosphorylation at the autophosphorylation site Y1068 and the transphosphorylation site Y845, implicating the involvement of Src kinase. Further investigation showed that O3 stimulation induced phosphorylation of Src at Y416, indicative of Src activation. Pharmacological inhibition of Src kinase activity abrogated O3-induced EGFR phosphorylation at tyrosines 1068 and 845. Moreover, pretreatment of BEAS-2B cells with inhibitor of either EGFR or Src kinase activities significantly blocked O3-induced IL-8 expression. CONCLUSION O3 exposure increased IL-8 expression through Src-mediated EGFR transactivation in HBEC.
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Affiliation(s)
- Weidong Wu
- School of Public Health, Xinxiang Medical University, Xinxiang, Henan Province, China
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Phillips RM, Dailey LA, Bair E, Samet JM, Allbritton NL. Ex vivo chemical cytometric analysis of protein tyrosine phosphatase activity in single human airway epithelial cells. Anal Chem 2014; 86:1291-7. [PMID: 24380370 PMCID: PMC3924180 DOI: 10.1021/ac403705c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We describe a novel method for the measurement of protein tyrosine phosphatase (PTP) activity in single human airway epithelial cells (hAECs) using capillary electrophoresis. This technique involved the microinjection of a fluorescent phosphopeptide that is hydrolyzed specifically by PTPs. Analyses in BEAS-2B immortalized bronchial epithelial cells showed rapid PTP-mediated dephosphorylation of the substrate (2.2 pmol min(-1) mg(-1)) that was blocked by pretreatment of the cells with the PTP inhibitors pervanadate, Zn(2+), and 1,2-naphthoquinone (76%, 69%, and 100% inhibition relative to PTP activity in untreated controls, respectively). These studies were then extended to a more physiologically relevant model system: primary hAECs cultured from bronchial brushings of living human subjects. In primary hAECs, dephosphorylation of the substrate occurred at a rate of 2.2 pmol min(-1) mg(-1) and was also effectively inhibited by preincubation of the cells with the inhibitors pervanadate, Zn(2+), and 1,2-naphthoquinone (91%, 88%, and 87% median PTP inhibition, respectively). Reporter proteolysis in single BEAS-2B cells occurred at a median rate of 43 fmol min(-1) mg(-1) resulting in a mean half-life of 20 min. The reporter displayed a similar median half-life of 28 min in these single primary cells. Finally, single viable epithelial cells (which were assayed for PTP activity immediately after collection by bronchial brushing of a human volunteer) showed dephosphorylation rates ranging from 0.34 to 36 pmol min(-1) mg(-1) (n = 6). These results demonstrate the utility and applicability of this technique for the ex vivo quantification of PTP activity in small, heterogeneous, human cells and tissues.
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Affiliation(s)
- Ryan M Phillips
- Department of Pharmacology, University of North Carolina , Chapel Hill, North Carolina 27599, United States
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Mutlu E, Warren SH, Matthews PP, King C, Linak WP, Kooter IM, Schmid JE, Ross JA, Gilmour MI, Demarini DM. Bioassay-directed fractionation and sub-fractionation for mutagenicity and chemical analysis of diesel exhaust particles. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2013; 54:719-36. [PMID: 24105890 DOI: 10.1002/em.21812] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 07/31/2013] [Accepted: 07/31/2013] [Indexed: 05/07/2023]
Abstract
Several types of diesel exhaust particles (DEPs) have been used for toxicology studies, including a high-organic automobile DEP (A-DEP) from Japan, and a low-organic forklift DEP developed by the National Institute of Standards and Technology (N-DEP). However, these DEPs were not characterized extensively for chemical composition or sub-fractionated and tested extensively for mutagenicity. We collected a compressor-generated DEP (C-DEP) and characterized it by conducting bioassay-directed fractionation of the extractable organics in Salmonella and correlating the results by hierarchical clustering with the concentrations of 32 polycyclic aromatic hydrocarbons (PAHs). Relative to A- and N-DEP, the mutagenic potency of C-DEP was intermediate in TA100 +S9 (PAH mutagenicity) but was lowest in TA98 -S9 (nitroarene mutagenicity). More than 50% of the mass of the extractable organics of C-DEP eluted in the nonpolar Fraction 1, and only ∼20% eluted in the moderately polar Fractions 2 and 3. However, most of the mutagenicity eluted in Fractions 2 and 3, similar to A-DEP but different from N-DEP. HPLC-derived mutagrams of 62 sub-fractions per fraction confirmed that most of the mutagenicity was due to moderately polar compounds. The diagnostic strains identified a strong role for PAHs, nitroarenes, aromatic amines, and oxy-PAHs in the mutagenicity of C-DEP. Hierarchical clustering confirmed the importance of oxy-PAHs but not that of nitroarenes. To our knowledge this is the first use of hierarchical clustering to correlate chemical composition with the mutagenicity of a complex mixture. The chemical analysis and mutagenicity of C-DEP described here makes C-DEP suitable for additional toxicological studies.
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Affiliation(s)
- Esra Mutlu
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina; Center for Environmental Medicine, Asthma and Lung Biology, University of North Carolina, Chapel Hill, North Carolina
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Phillips RM, Bair E, Lawrence DS, Sims CE, Allbritton NL. Measurement of protein tyrosine phosphatase activity in single cells by capillary electrophoresis. Anal Chem 2013; 85:6136-42. [PMID: 23682679 DOI: 10.1021/ac401106e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A fluorescent peptide substrate was used to measure dephosphorylation by protein tyrosine phosphatases (PTP) in cell lysates and single cells and to investigate the effect of environmental toxins on PTP activity in these systems. Dephosphorylation of the substrate by PTPN1 and PTPN2 obeyed Michaelis-Menten kinetics, with KM values of 770 ± 250 and 290 ± 54 nM, respectively. Dose-response curves and IC50 values were determined for the inhibition of these two enzymes by the environmental toxins Zn(2+) and 1,2-naphthoquinone, as well as pervanadate. In A431 cell lysates, the reporter was a poor substrate for peptidases (degradation rate of 100 ± 8.2 fmol min(-1) mg(-1)) but an excellent substrate for phosphatases (dephosphorylation rate of 1.4 ± 0.3 nmol min(-1) mg(-1)). Zn(2+), 1,2-naphthoquinone, and pervanadate inhibited dephosphorylation of the reporter in cell lysates with IC50 values of 470 nM, 35 μM, and 100 nM, respectively. Dephosphorylation of the reporter, following loading into living single cells, occurred at rates of at least 2 pmol min(-1) mg(-1). When single cells were exposed to 1,2-naphthoquinone (50 μM), Zn(2+) (100 μM), and pervandate (1 mM), dephosphorylation was inhibited with median values and first and third quartile values of 41 (Q1 = 0%, Q3 = 96%), 50 (Q1 = 46%, Q3 = 74%), and 53% (Q1 = 36%, Q3 = 77%), respectively, demonstrating both the impact of these toxic exposures on cell signaling and the heterogeneity of response between cells. This approach will provide a valuable tool for the study of PTP dynamics, particularly in small, heterogeneous populations such as human biopsy specimens.
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Affiliation(s)
- Ryan M Phillips
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Inflammation-related effects of diesel engine exhaust particles: studies on lung cells in vitro. BIOMED RESEARCH INTERNATIONAL 2013; 2013:685142. [PMID: 23509760 PMCID: PMC3586454 DOI: 10.1155/2013/685142] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/04/2013] [Accepted: 01/15/2013] [Indexed: 01/17/2023]
Abstract
Diesel exhaust and its particles (DEP) have been under scrutiny for health effects in humans. In the development of these effects inflammation is regarded as a key process. Overall, in vitro studies report similar DEP-induced changes in markers of inflammation, including cytokines and chemokines, as studies in vivo. In vitro studies suggest that soluble extracts of DEP have the greatest impact on the expression and release of proinflammatory markers. Main DEP mediators of effects have still not been identified and are difficult to find, as fuel and engine technology developments lead to continuously altered characteristics of emissions. Involved mechanisms remain somewhat unclear. DEP extracts appear to comprise components that are able to activate various membrane and cytosolic receptors. Through interactions with receptors, ion channels, and phosphorylation enzymes, molecules in the particle extract will trigger various cell signaling pathways that may lead to the release of inflammatory markers directly or indirectly by causing cell death. In vitro studies represent a fast and convenient system which may have implications for technology development. Furthermore, knowledge regarding how particles elicit their effects may contribute to understanding of DEP-induced health effects in vivo, with possible implications for identifying susceptible groups of people and effect biomarkers.
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Gehrke H, Frühmesser A, Pelka J, Esselen M, Hecht LL, Blank H, Schuchmann HP, Gerthsen D, Marquardt C, Diabaté S, Weiss C, Marko D. In vitrotoxicity of amorphous silica nanoparticles in human colon carcinoma cells. Nanotoxicology 2012; 7:274-93. [DOI: 10.3109/17435390.2011.652207] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Hyseni X, Soukup JM, Huang YCT. Pollutant particles induce arginase II in human bronchial epithelial cells. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2012; 75:624-636. [PMID: 22712848 DOI: 10.1080/15287394.2012.688479] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Exposure to particulate matter (PM) is associated with adverse pulmonary effects, including induction and exacerbation of asthma. Recently arginase was shown to play an important role in the pathogenesis of asthma. In this study, it was postulated that PM exposure might induce arginase. Human bronchial epithelial cells (HBEC) obtained from normal individuals by endobronchial brushings cultured on an air-liquid interface were incubated with fine Chapel Hill particles (PM₂.₅, 100 μg/ml) for up to 72 h. Arginase activity, protein expression, and mRNA of arginase I and arginase II were measured. PM₂.₅ increased arginase activity in a time-dependent manner. The rise was primarily due to upregulation of arginase II. PD153035 (10 μM), an epidermal growth factor (EGF) receptor antagonist, attenuated the PM₂.₅-induced elevation in arginase activity and arginase II expression. Treatment of HBEC with human EGF increased arginase activity and arginase II expression. Pretreatment with catalase (200 U/ml), superoxide dismutase (100 U/ml), or apocynin (5 μg/ml), an NAD(P)H oxidase inhibitor, did not markedly affect arginase II expression. Treatment of HBEC with arginase II siRNA inhibited the expression of arginase II by 60% and increased IL-8 release induced by PM₂.₅. These results indicate that PM exposure upregulates arginase II activity and expression in human bronchial epithelial cells, in part via EGF-dependent mechanisms independent of oxidative stress. The elevated arginase II activity and expression may be a mechanism underlying adverse effects induced by PM exposure in asthma patients.
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Affiliation(s)
- Xhevahire Hyseni
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
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Dodmane PR, Schulte NA, Heires AJ, Band H, Romberger DJ, Toews ML. Airway epithelial epidermal growth factor receptor mediates hogbarn dust-induced cytokine release but not Ca2+ response. Am J Respir Cell Mol Biol 2011; 45:882-8. [PMID: 21441380 DOI: 10.1165/rcmb.2010-0419oc] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A subset of workers in swine confinement facilities develops chronic respiratory disease. An aqueous extract of dust from these facilities (hogbarn dust extract [HDE]) induces IL-6 and IL-8 release and several other responses in isolated airway epithelial cells. The cell membrane receptors by which HDE initiates these responses have not been identified. Because several other inhaled agents induce airway epithelial cell responses through epidermal growth factor receptor (EGFR) activation, we hypothesized that HDE would activate EGFRs and that EGFRs would be required for some of the responses to HDE. Exposure of Beas-2B cells to HDE caused EGFR phosphorylation and downstream ERK activation, and both responses were blocked by the EGFR-selective kinase inhibitor AG1478. AG1478 and EGFR-neutralizing antibody reduced HDE-stimulated IL-6 and IL-8 release by about half. Similar EGFR phosphorylation and requirement of EGFRs for maximal IL-6 and IL-8 release were found with primary isolates of human bronchial epithelial cells. Because HDE-stimulated IL-6 and IL-8 release involve the Ca(2+)-dependent protein kinase Cα, we hypothesized that HDE would induce intracellular Ca(2+) mobilization. HDE exposure induced intracellular Ca(2+) mobilization in Beas-2B cells and in primary cell isolates, but this response was neither mimicked by EGF nor inhibited by AG1478. Thus, HDE activates EGFRs and their downstream signaling, and EGFR activation is required for some but not all airway epithelial cell responses to HDE.
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Affiliation(s)
- Puttappa R Dodmane
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
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Samet JM, Tal TL. Toxicological disruption of signaling homeostasis: tyrosine phosphatases as targets. Annu Rev Pharmacol Toxicol 2010; 50:215-35. [PMID: 20055703 DOI: 10.1146/annurev.pharmtox.010909.105841] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The protein tyrosine phosphatases (PTPs) consist of a diverse group of enzymes whose activity opposes that of the tyrosine kinases. As such, the PTPs have critical roles in maintaining signaling quiescence in resting cells and in restoring homeostasis by effecting signal termination. Interest in these enzymes has increased in recent years following the discovery that the activity of PTPs is modulated through redox mechanisms during signaling. The molecular features that enable redox regulation of PTPs during physiological signaling also render them highly susceptible to oxidative and electrophilic inactivation by a broad spectrum of structurally disparate xenobiotic compounds. The loss of PTP activity results in a profound disregulation of protein phosphotyrosine metabolism, leading to widespread and persistent activation of signaling cascades in the cell.
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Affiliation(s)
- James M Samet
- U.S. Environmental Protection Agency, Chapel Hill, North Carolina, USA.
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Differential transcriptional regulation of IL-8 expression by human airway epithelial cells exposed to diesel exhaust particles. Toxicol Appl Pharmacol 2010; 243:46-54. [DOI: 10.1016/j.taap.2009.11.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/05/2009] [Accepted: 11/06/2009] [Indexed: 11/18/2022]
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