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Liu TT, Sun HF, Han YX, Zhan Y, Jiang JD. The role of inflammation in silicosis. Front Pharmacol 2024; 15:1362509. [PMID: 38515835 PMCID: PMC10955140 DOI: 10.3389/fphar.2024.1362509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 02/21/2024] [Indexed: 03/23/2024] Open
Abstract
Silicosis is a chronic illness marked by diffuse fibrosis in lung tissue resulting from continuous exposure to SiO2-rich dust in the workplace. The onset and progression of silicosis is a complicated and poorly understood pathological process involving numerous cells and molecules. However, silicosis poses a severe threat to public health in developing countries, where it is the most prevalent occupational disease. There is convincing evidence supporting that innate and adaptive immune cells, as well as their cytokines, play a significant role in the development of silicosis. In this review, we describe the roles of immune cells and cytokines in silicosis, and summarize current knowledge on several important inflammatory signaling pathways associated with the disease, aiming to provide novel targets and strategies for the treatment of silicosis-related inflammation.
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Affiliation(s)
| | | | | | - Yun Zhan
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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2
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Plazyo O, Sheng JJ, Jin JP. Downregulation of calponin 2 contributes to the quiescence of lung macrophages. Am J Physiol Cell Physiol 2019; 317:C749-C761. [PMID: 31365293 PMCID: PMC6850996 DOI: 10.1152/ajpcell.00036.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 07/08/2019] [Accepted: 07/23/2019] [Indexed: 12/14/2022]
Abstract
Calponin 2 is an actin cytoskeleton-associated regulatory protein that inhibits the activity of myosin-ATPase and cytoskeleton dynamics. Recent studies have demonstrated that deletion of calponin 2 restricts the proinflammatory activation of macrophages in atherosclerosis and arthritis to attenuate the disease progression in mice. Here we demonstrate that the levels of calponin 2 vary among different macrophage populations, which may reflect their adaptation to specific tissue microenvironment corresponding to specific functional states. Interestingly, lung resident macrophages express significantly lower calponin 2 than peritoneal resident macrophages, which correlates with decreased substrate adhesion and reduced expression of proinflammatory cytokines and a proresolution phenotype. Deletion of calponin 2 in peritoneal macrophages also decreased substrate adhesion and downregulated the expression of proinflammatory cytokines. Providing the first line of defense against microbial invasion while receiving constant exposure to extrinsic antigens, lung macrophages need to maintain a necessary level of activity while limiting exaggerated inflammatory reaction. Therefore, their low level of calponin 2 may reflect an important physiological adaption. Downregulation of calponin 2 in macrophages may be targeted as a cytoskeleton-based novel mechanism, possibly via endoplasmic reticulum stress altering the processing and secretion of cytokines, to regulate immune response and promote quiescence for the treatment of inflammatory diseases.
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Affiliation(s)
- Olesya Plazyo
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Juan-Juan Sheng
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - J-P Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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3
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Gobba NAEK, Hussein Ali A, El Sharawy DE, Hussein MA. The potential hazardous effect of exposure to iron dust in Egyptian smoking and nonsmoking welders. ARCHIVES OF ENVIRONMENTAL & OCCUPATIONAL HEALTH 2018; 73:189-202. [PMID: 28375782 DOI: 10.1080/19338244.2017.1314930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 03/28/2017] [Indexed: 06/07/2023]
Abstract
Exposure to iron dust and welding fumes is widespread and may increase the risk of lung inflammation. The aim of this study was to identify associations between exposure to iron/welding fumes and the levels of inflammatory parameters and allergic mediators among 120 Egyptian men. Forty nonsmoking and 40 smoking Egyptian welders as well as 40 healthy volunteers who were never exposed to welding fumes and were nonsmoking were enrolled in the study. Peak expiratory flow rates (PEFR) assessed at the end of the shift of work on working days revealed an impairment in lung function, with the smoking workers showing the worse results, followed by nonsmoking workers, as compared to healthy volunteers. Moreover, the results of the present study showed a significant increase in serum iron and immunoglobulin E, as well as plasma thiobarbaturic acid reactive substances, C-reactive protein, tumor necrosis factor-alpha, haptoglobin, interleukin-2, interleukin-6 and interleukin-23 histamine, lactate dehydrogenase isoenzyme-3, and calcitonin. In addition, the results revealed significant decrease in plasma α-1-antitrypsin and serum transferrin, as well as blood activities of antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase (as compared with control group). However, there was a nonsignificant change in arginase and α-L-fucosidase in smoking and nonsmoking welders exposed to iron dust and welding fumes. In conclusion, occupational exposure to iron dust and welding fumes increases lung inflammation risk among Egyptian blacksmith workers, a condition that worsens with smoking.
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Affiliation(s)
- Naglaa Abd El Khalik Gobba
- a Department of Pharmacology and Toxicology, College of Pharmacy , Misr University for Science and Technology (MUST) , 6th of October City , Egypt
| | - Abdelmaksoud Hussein Ali
- b Department of Biochemistry, Faculty of Veterinary Medicine , Benha University , Qalioubeya , Egypt
| | - Dalia E El Sharawy
- c Department of Chest Diseases, Faculty of Medicine , Tanta University , Cairo , Egypt
| | - Mohammed Abdalla Hussein
- d Department of Biochemistry, Faculty of Applied Medical Sciences , October 6 University , 6th of October City , Egypt
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4
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Kim JG, Choi KC, Hong CW, Park HS, Choi EK, Kim YS, Park JB. Tyr42 phosphorylation of RhoA GTPase promotes tumorigenesis through nuclear factor (NF)-κB. Free Radic Biol Med 2017; 112:69-83. [PMID: 28712859 DOI: 10.1016/j.freeradbiomed.2017.07.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 06/19/2017] [Accepted: 07/11/2017] [Indexed: 01/01/2023]
Abstract
Dysregulation of reactive oxygen species (ROS) levels is implicated in the pathogenesis of several diseases, including cancer. However, the molecular mechanisms for ROS in tumorigenesis have not been well established. In this study, hydrogen peroxide activated nuclear factor-κB (NF-κB) and RhoA GTPase. In particular, we found that hydrogen peroxide lead to phosphorylation of RhoA at Tyr42 via tyrosine kinase Src. Phospho-Tyr42 (p-Tyr42) residue of RhoA is a binding site for Vav2, a guanine nucleotide exchange factor (GEF), which then activates p-Tyr42 form of RhoA. P-Tyr42 RhoA then binds to IκB kinase γ (IKKγ), leading to IKKβ activation. Furthermore, RhoA WT and phospho-mimic RhoA, RhoA Y42E, both promoted tumorigenesis, whereas the dephospho-mimic RhoA, RhoA Y42F suppressed it. In addition, hydrogen peroxide induced NF-κB activation and cell proliferation, along with expression of c-Myc and cyclin D1 in the presence of RhoA WT and RhoA Y42E, but not RhoA Y42F. Indeed, levels of p-Tyr42 Rho, p-Src, and p-65 are significantly increased in human breast cancer tissues and show correlations between each of the two components. Conclusively, the posttranslational modification of as RhoA p-Tyr42 may be essential for promoting tumorigenesis in response to generation of ROS.
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Affiliation(s)
- Jae-Gyu Kim
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Kyoung-Chan Choi
- Department of Pathology, Chuncheon Sacred Hospital Hallym University, Chuncheon 24252, Republic of Korea
| | - Chang-Won Hong
- Department of Physiology, Kyungpook National University School of Medicine, Daegu, Gyeongsangbuk-do 41944, Republic of Korea
| | - Hwee-Seon Park
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Eun-Kyoung Choi
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Republic of Korea
| | - Yong-Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Republic of Korea; Department of Microbiology, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Jae-Bong Park
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea; Institute of Cell Differentiation and Ageing, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea.
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5
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Kim JG, Kwon HJ, Wu G, Park Y, Lee JY, Kim J, Kim SC, Choe M, Kang SG, Seo GY, Kim PH, Park JB. RhoA GTPase oxidation stimulates cell proliferation via nuclear factor-κB activation. Free Radic Biol Med 2017; 103:57-68. [PMID: 27974245 DOI: 10.1016/j.freeradbiomed.2016.12.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 12/09/2016] [Accepted: 12/10/2016] [Indexed: 12/15/2022]
Abstract
Reactive oxygen species (ROS) produced by many kinds of stimuli are essential for cellular signaling including cell proliferation. The dysregulation of ROS, therefore, is related to a variety of diseases including cancer. However, it was not clearly elucidated how ROS regulate cell proliferation and tumorigenesis. In this study, we investigated a mechanism by which the oxidation of RhoA GTPase regulates nuclear factor-κB (NF-κB) and cell proliferation. Hydrogen peroxide activated NF-κB and RhoA GTPase, but did not activate RhoA C16/20A mutant, an oxidation-resistant form. Remarkably, the oxidation of RhoA reduced its affinity towards RhoGDI, leading to the dissociation of RhoA-RhoGDI complex. Si-Vav2, a guanine nucleotide exchange factor (GEF), inhibited RhoA activation upon hydrogen peroxide. The oxidized RhoA (oxRhoA)-GTP was readily bound to IκB kinase γ (IKKγ), whereas oxidized RhoGDI did not bind to IKKγ. The oxRhoA-GTP bound to IKKγ activated IKKβ, leading to IκB phosphorylation and degradation, consequently NF-κB activation. Hydrogen peroxide induced cell proliferation, but RhoA C16/20A mutant suppressed cell proliferation and tumorigenesis. Conclusively, RhoA oxidation at Cys16/20 is critically involved in cell proliferation and tumorigenesis through NF-κB activation in response to ROS.
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Affiliation(s)
- Jae-Gyu Kim
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Hyung-Joo Kwon
- Department of Microbiology, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea; Center for Medical Science Research, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Guang Wu
- Center for Medical Science Research, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Yohan Park
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Jae-Yong Lee
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea; Institute of Cell Differentiation and Ageing, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Jaebong Kim
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea; Institute of Cell Differentiation and Ageing, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Sung-Chan Kim
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea; Institute of Cell Differentiation and Ageing, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea
| | - Myoen Choe
- Department of Bio-Health and Technology, School of Biomedical Science and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-do 24341, Republic of Korea
| | - Seung Goo Kang
- Division of Biomedical Convergence, School of Biomedical Science and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-do 24341, Republic of Korea
| | - Goo-Young Seo
- Department of Molecular Bioscience, School of Biomedical Science and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-do 24341, Republic of Korea
| | - Pyeung-Hyeun Kim
- Department of Molecular Bioscience, School of Biomedical Science and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-do 24341, Republic of Korea
| | - Jae-Bong Park
- Department of Biochemistry, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea; Center for Medical Science Research, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea; Institute of Cell Differentiation and Ageing, Hallym University College of Medicine, Chuncheon, Kangwon-do 24252, Republic of Korea.
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6
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Mossman BT, Glenn RE. Bioreactivity of the crystalline silica polymorphs, quartz and cristobalite, and implications for occupational exposure limits (OELs). Crit Rev Toxicol 2013; 43:632-60. [PMID: 23863112 DOI: 10.3109/10408444.2013.818617] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Silica or silicon dioxides (SiO₂) are naturally occurring substances that comprise the vast majority of the earth's crust. Because of their prevalence and commercial applications, they have been widely studied for their potential to induce pulmonary fibrosis and other disorders. Historically, the focus in the workplace has been on the development of inflammation and fibrotic lung disease, the basis for promulgating workplace standards to protect workers. Crystalline silica (CS) polymorphs, predominantly quartz and cristobalite, are used in industry but are different in their mineralogy, chemistry, surface features, size dimensions and association with other elements naturally and during industrial applications. Epidemiologic, clinical and experimental studies in the literature historically have predominantly focused on quartz polymorphs. Thus, in this review, we summarize past scientific evaluations and recent peer-reviewed literature with an emphasis on cristobalite, in an attempt to determine whether quartz and cristobalite polymorphs differ in their health effects, toxicity and other properties that may dictate the need for various standards of protection in the workplace. In addition to current epidemiological and clinical reports, we review in vivo studies in rodents as well as cell culture studies that shed light on mechanisms intrinsic to the toxicity, altered cell responses and protective or defense mechanisms in response to these minerals. The medical and scientific literature indicates that the mechanisms of injury and potential causation of inflammation and fibrotic lung disease are similar for quartz and cristobalite. Our analysis of these data suggests similar occupational exposure limits (OELs) for these minerals in the workplace.
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Affiliation(s)
- Brooke T Mossman
- Department of Pathology, University of Vermont College of Medicine, Burlington, VT 05405-0068, USA.
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Chu Z, Huang Y, Li L, Tao Q, Li Q. Physiological pathway of human cell damage induced by genotoxic crystalline silica nanoparticles. Biomaterials 2012; 33:7540-6. [DOI: 10.1016/j.biomaterials.2012.06.073] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 06/26/2012] [Indexed: 10/28/2022]
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Scherbart AM, Langer J, Bushmelev A, van Berlo D, Haberzettl P, van Schooten FJ, Schmidt AM, Rose CR, Schins RPF, Albrecht C. Contrasting macrophage activation by fine and ultrafine titanium dioxide particles is associated with different uptake mechanisms. Part Fibre Toxicol 2011; 8:31. [PMID: 21995556 PMCID: PMC3214143 DOI: 10.1186/1743-8977-8-31] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 10/13/2011] [Indexed: 11/29/2022] Open
Abstract
Inhalation of (nano)particles may lead to pulmonary inflammation. However, the precise mechanisms of particle uptake and generation of inflammatory mediators by alveolar macrophages (AM) are still poorly understood. The aim of this study was to investigate the interactions between particles and AM and their associated pro-inflammatory effects in relation to particle size and physico-chemical properties. NR8383 rat lung AM were treated with ultrafine (uf), fine (f) TiO2 or fine crystalline silica (DQ12 quartz). Physico-chemical particle properties were investigated by transmission electron microscopy, elemental analysis and thermogravimetry. Aggregation and agglomeration tendency of the particles were determined in assay-specific suspensions by means of dynamic light scattering. All three particle types were rapidly taken up by AM. DQ12 and ufTiO2 , but not fTiO2 , caused increased extracellular reactive oxygen species (ROS), heme oxygenase 1 (HO-1) mRNA expression and tumor necrosis factor (TNF)-α release. Inducible nitric oxide synthase (iNOS) mRNA expression was increased most strongly by ufTiO2 , while DQ12 exclusively triggered interleukin (IL) 1β release. However, oscillations of intracellular calcium concentration and increased intracellular ROS were observed with all three samples. Uptake inhibition experiments with cytochalasin D, chlorpromazine and a Fcγ receptor II (FcγRII) antibody revealed that the endocytosis of fTiO2 by the macrophages involves actin-dependent phagocytosis and macropinocytosis as well as clathrin-coated pit formation, whereas the uptake of ufTiO2 was dominated by FcγIIR. The uptake of DQ12 was found to be significantly reduced by all three inhibitors. Our findings suggest that the contrasting AM responses to fTiO2 , ufTiO2 and DQ12 relate to differences in the involvement of specific uptake mechanisms.
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Affiliation(s)
- Agnes M Scherbart
- IUF - Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
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9
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van Berlo D, Knaapen AM, van Schooten FJ, Schins RPF, Albrecht C. NF-kappaB dependent and independent mechanisms of quartz-induced proinflammatory activation of lung epithelial cells. Part Fibre Toxicol 2010; 7:13. [PMID: 20492675 PMCID: PMC2885999 DOI: 10.1186/1743-8977-7-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 05/21/2010] [Indexed: 11/10/2022] Open
Abstract
In the initiation and progression of pulmonary inflammation, macrophages have classically been considered as a crucial cell type. However, evidence for the role of epithelial type II cells in pulmonary inflammation has been accumulating. In the current study, a combined in vivo and in vitro approach has been employed to investigate the mechanisms of quartz-induced proinflammatory activation of lung epithelial cells. In vivo, enhanced expression of the inflammation- and oxidative stress-related genes HO-1 and iNOS was found on the mRNA level in rat lungs after instillation with DQ12 respirable quartz. Activation of the classical NF-kappaB pathway in macrophages and type II pneumocytes was indicated by enhanced immunostaining of phospho-IkappaBalpha in these specific lung cell types. In vitro, the direct, particle-mediated effect on proinflammatory signalling in a rat lung epithelial (RLE) cell line was compared to the indirect, macrophage product-mediated effect. Treatment with quartz particles induced HO-1 and COX-2 mRNA expression in RLE cells in an NF-kappaB independent manner. Supernatant from quartz-treated macrophages rapidly activated the NF-kappaB signalling pathway in RLE cells and markedly induced iNOS mRNA expression up to 2000-fold compared to non-treated control cells. Neutralisation of TNFalpha and IL-1beta in macrophage supernatant did not reduce its ability to elicit NF-kappaB activation of RLE cells. In addition the effect was not modified by depletion or supplementation of intracellular glutathione. The results from the current work suggest that although both oxidative stress and NF-kappaB are likely involved in the inflammatory effects of toxic respirable particles, these phenomena can operate independently on the cellular level. This might have consequences for in vitro particle hazard testing, since by focusing on NF-kappaB signalling one might neglect alternative inflammatory pathways.
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Affiliation(s)
- Damien van Berlo
- Institut für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine-Universität Düsseldorf gGmbH, Germany
| | - Ad M Knaapen
- Department of Health Risk Analysis and Toxicology, Maastricht University, the Netherlands
- Department of Toxicology and Drug Disposition, Schering-Plough, the Netherlands
| | | | - Roel PF Schins
- Institut für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine-Universität Düsseldorf gGmbH, Germany
| | - Catrin Albrecht
- Institut für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine-Universität Düsseldorf gGmbH, Germany
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Li X, Hu Y, Jin Z, Jiang H, Wen J. Silica-induced TNF-alpha and TGF-beta1 expression in RAW264.7 cells are dependent on Src-ERK/AP-1 pathways. Toxicol Mech Methods 2010; 19:51-8. [PMID: 19778233 DOI: 10.1080/15376510802354201] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The cytokines secreted by lung macrophages have been shown to play a critical role in the pathogenesis of silicosis, tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta1 (TGF-beta1) are prominent cytokines in silicosis, but the underlying mechanism remains to be determined. The aim of the present study was to investigate the roles of Src-mitogen-activated protein kinase (MAPKs)/activator protein-1 (AP-1) signaling pathways in silica-induced TNF-alpha and TGF-beta1 expression in macrophage cells (RAW264.7). It was found that silica activated Src, p38 kinase, and extracellular signal-regulated kinase (ERK) in RAW264.7 cells. The induction of TNF-alpha and TGF-beta1 by silica was suppressed by Src inhibitor (PP1), ERK inhibitor (PD98059), but not by p38 kinase inhibitor (SB203580). Dominant negative mutant c-Jun (TAM67) inhibited silica-induced AP-1 DNA binding activity and downregulated the TNF-alpha and TGF-beta1 expression. In addition, PD98059 but not SB203580 inhibited the AP-1 DNA binding activity induced by silica. Based on these findings, it was conclude that Src-ERK/AP-1 signaling pathways are involved in the TNF-alpha and TGF-beta1 expression induced by silica in macrophages.
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Affiliation(s)
- Xiang Li
- Department of Pathology, Xiangya Medical School, Central South University, Changsha 410013, PR China
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Di Giuseppe M, Gambelli F, Hoyle GW, Lungarella G, Studer SM, Richards T, Yousem S, McCurry K, Dauber J, Kaminski N, Leikauf G, Ortiz LA. Systemic inhibition of NF-kappaB activation protects from silicosis. PLoS One 2009; 4:e5689. [PMID: 19479048 PMCID: PMC2682759 DOI: 10.1371/journal.pone.0005689] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 04/07/2009] [Indexed: 11/29/2022] Open
Abstract
Background Silicosis is a complex lung disease for which no successful treatment is available and therefore lung transplantation is a potential alternative. Tumor necrosis factor alpha (TNFα) plays a central role in the pathogenesis of silicosis. TNFα signaling is mediated by the transcription factor, Nuclear Factor (NF)-κB, which regulates genes controlling several physiological processes including the innate immune responses, cell death, and inflammation. Therefore, inhibition of NF-κB activation represents a potential therapeutic strategy for silicosis. Methods/Findings In the present work we evaluated the lung transplant database (May 1986–July 2007) at the University of Pittsburgh to study the efficacy of lung transplantation in patients with silicosis (n = 11). We contrasted the overall survival and rate of graft rejection in these patients to that of patients with idiopathic pulmonary fibrosis (IPF, n = 79) that was selected as a control group because survival benefit of lung transplantation has been identified for these patients. At the time of lung transplantation, we found the lungs of silica-exposed subjects to contain multiple foci of inflammatory cells and silicotic nodules with proximal TNFα expressing macrophage and NF-κB activation in epithelial cells. Patients with silicosis had poor survival (median survival 2.4 yr; confidence interval (CI): 0.16–7.88 yr) compared to IPF patients (5.3 yr; CI: 2.8–15 yr; p = 0.07), and experienced early rejection of their lung grafts (0.9 yr; CI: 0.22–0.9 yr) following lung transplantation (2.4 yr; CI:1.5–3.6 yr; p<0.05). Using a mouse experimental model in which the endotracheal instillation of silica reproduces the silica-induced lung injury observed in humans we found that systemic inhibition of NF-κB activation with a pharmacologic inhibitor (BAY 11-7085) of IκBα phosphorylation decreased silica-induced inflammation and collagen deposition. In contrast, transgenic mice expressing a dominant negative IκBα mutant protein under the control of epithelial cell specific promoters demonstrate enhanced apoptosis and collagen deposition in their lungs in response to silica. Conclusions Although limited by its size, our data support that patients with silicosis appear to have poor outcome following lung transplantation. Experimental data indicate that while the systemic inhibition of NF-κB protects from silica-induced lung injury, epithelial cell specific NF-κB inhibition appears to aggravate the outcome of experimental silicosis.
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Affiliation(s)
- Michelangelo Di Giuseppe
- Division of Occupational and Environmental Medicine, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Federica Gambelli
- Division of Occupational and Environmental Medicine, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Gary W. Hoyle
- Department of Environmental and Occupational Health Sciences, School of Public Health and Informational Sciences, University of Louisville, Louisville, Kentucky, United States of America
| | | | - Sean M. Studer
- Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Thomas Richards
- Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Sam Yousem
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Ken McCurry
- Department of Thoracic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - James Dauber
- Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Naftali Kaminski
- Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - George Leikauf
- Division of Occupational and Environmental Medicine, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Luis A. Ortiz
- Division of Occupational and Environmental Medicine, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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Gulumian M, Borm PJA, Vallyathan V, Castranova V, Donaldson K, Nelson G, Murray J. Mechanistically identified suitable biomarkers of exposure, effect, and susceptibility for silicosis and coal-worker's pneumoconiosis: a comprehensive review. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2006; 9:357-95. [PMID: 16990219 DOI: 10.1080/15287390500196537] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Clinical detection of silicosis is currently dependent on radiological and lung function abnormalities, both late manifestations of disease. Markers of prediction and early detection of pneumoconiosis are imperative for the implementation of timely intervention strategies. Understanding the underlying mechanisms of the etiology of coal workers pneumoconiosis (CWP) and silicosis was essential in proposing numerous biomarkers that have been evaluated to assess effects following exposure to crystalline silica and/or coal mine dust. Human validation studies have substantiated some of these proposed biomarkers and argued in favor of their use as biomarkers for crystalline silica- and CWP-induced pneumoconiosis. A number of "ideal" biological markers of effect were identified, namely, Clara cell protein-16 (CC16) (serum), tumor necrosis factor-alpha (TNF-alpha) (monocyte release), interleukin-8 (IL-8) (monocyte release), reactive oxygen species (ROS) measurement by chemiluminescence (neutrophil release), 8-isoprostanes (serum), total antioxidant levels measured by total equivalent antioxidant capacity (TEAC), glutathione, glutathione peroxidase activity, glutathione S-transferase activity, and platelet-derived growth factor (PDGF) (serum). TNF-alpha polymorphism (blood cellular DNA) was identified as a biomarker of susceptibility. Further studies are planned to test the validity and feasibility of these biomarkers to detect either high exposure to crystalline silica and early silicosis or susceptibility to silicosis in gold miners in South Africa.
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Affiliation(s)
- M Gulumian
- Department of Toxicology and Biochemistry Research, National Institute for Occupational Health, Johannesburg, South Africa.
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13
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Mechanisms of silica-induced IL-8 release from A549 cells: initial kinase-activation does not require EGFR activation or particle uptake. Toxicology 2006; 227:105-16. [PMID: 16963169 DOI: 10.1016/j.tox.2006.07.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 07/20/2006] [Accepted: 07/24/2006] [Indexed: 11/15/2022]
Abstract
Understanding how mineral particles trigger cellular responses is crucial in order to elucidate what characteristics determine their harmful effects. It is not clear whether cellular effects are triggered through the cell membrane or require particle uptake. However, studies with asbestos suggest that activation of the epidermal growth factor receptor (EGFR) may be important. We have previously reported that crystalline silica-induced interleukin (IL)-8 release from human lung epithelial cells (A549) was regulated through Src family kinases (SFKs) and the mitogen-activated protein kinases (MAPKs) p38 and extracellular signal-regulated kinase (ERK)-1 and -2. The present study shows that SFK and p38 phosphorylation increased almost immediately upon crystalline silica exposure, whereas ERK1/2 phosphorylation increased after 10 min of exposure. The p38 inhibitor SB202190 increased the silica-induced ERK1/2 phosphorylation suggesting that p38 activity may attenuate activation of ERK1/2. Scanning electron microscopy showed that some silica particles were phagocytosed between 1 and 4h of exposure, but that the majority remained bound by microvilli on the cell surface. The EGFR inhibitor AG1478 attenuated both silica-induced IL-8 release and phosphorylation of SFKs and ERK1/2. However, AG1478 also inhibited the respective background levels, and the EGFR was not phosphorylated at the onset of silica exposure. The results suggest that crystalline silica triggers p38 and SFK-ERK1/2 signaling through interactions with membrane components as both pathways were rapidly activated prior to particle internalization. However, the silica-induced up-regulation of IL-8 release through the SFK-ERK1/2 pathway does not appear to be initiated through activation of the EGFR, although basal EGFR activity may affect the magnitude of the responses.
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14
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Schneider JC, Card GL, Pfau JC, Holian A. Air pollution particulate SRM 1648 causes oxidative stress in RAW 264.7 macrophages leading to production of prostaglandin E2, a potential Th2 mediator. Inhal Toxicol 2006; 17:871-7. [PMID: 16282164 DOI: 10.1080/08958370500244498] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Particulates in air pollution have been strongly associated with asthma symptoms. These particulates are a conglomeration of many components, including metals, polyaromatic hydrocarbons, and lipopolysaccharide, that may cause oxidative stress upon uptake by alveolar macrophages. The objective of this study was to assess whether uptake of a model air particulate (SRM 1648) causes oxidative stress in macrophages resulting in the production of the eicosanoid mediator prostaglandin E(2) (PGE(2)) that might exacerbate asthma. SRM 1648 suspended in phosphate-buffered saline (PBS) was introduced into wells with plated RAW 264.7 monocyte/macrophages. Following incubation of SRM 1648 with RAW 264.7 macrophages, prostaglandin E(2) was measured by enzyme immunosorbent assay (EIA), and oxidative stress was assessed by the levels of intracellular reduced glutathione (GSH) as well as by the oxidation of dihydrodichlorofluorescein (H(2)DCFDA) to the fluorescent dichlorofluoresecein (DCF). The results indicated that SRM 1648 caused oxidative stress in RAW 264.7 macrophages, as shown by a compensatory increase in GSH levels in comparison to the controls of titanium dioxide and media alone. Prostaglandin E(2) levels significantly increased at the 3-, 6-, and 12-h time points. Introduction of GSH ester to buffer against oxidative stress was able to block the elevation of PGE(2). The data show that SRM 1648 causes oxidative stress in RAW 264.7 macrophages resulting in formation of the potential Th2 mediator prostaglandin E(2).
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Affiliation(s)
- Jordan C Schneider
- Center for Environmental Health Sciences, University of Montana, Department of Biomedical and Pharmaceutical Sciences, Missoula, Montana, USA.
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15
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Kang JL, Jung HJ, Lee K, Kim HR. Src Tyrosine Kinases Mediate Crystalline Silica-Induced NF-κB Activation through Tyrosine Phosphorylation of IκB-α and p65 NF-κB in RAW 264.7 Macrophages. Toxicol Sci 2006; 90:470-7. [PMID: 16431847 DOI: 10.1093/toxsci/kfj096] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Protein tyrosine kinases (PTKs) and mitogen-activated protein kinases (MAPKs) have been demonstrated to play a crucial role in the signaling pathways induced by silica. In the present study, we investigated whether Src family TKs play a role in crystalline silica-induced NF-kappaB activation and whether NF-kappaB activation requires Src TK-dependent MAPK activity in RAW 264.7 cells, a mouse peritoneal macrophage cell line. Selective Src TK inhibitors, damnacanthal or PP1, inhibited silica-induced NF-kappaB activation in a dose-dependent manner. Furthermore, these kinase inhibitors suppressed silica-induced tyrosine phosphorylation of IkappaB-alpha and p65 NF-kappaB. Within a similar time frame, c-Src and Lck were physically associated with IkappaB-alpha and with p65 NF-kappaB. Silica stimulated the phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2), but not p38 MAPK and c-Jun NH(2)-terminal kinase 1 and 2 (JNK1/2). Damnacanthal or PP1 substantially blocked the silica-induced activation of ERK1/2. Moreover, PD98059, an inhibitor of ERK1/2, or SB203580, an inhibitor of p38 MAPK, failed to inhibit silica-induced NF-kappaB activation. These results suggest that c-Src and Lck act for silica-induced NF-kappaB activation by mediating the tyrosine phosphorylations of IkappaB-alpha and p65 NF-kappaB. However, the Src TK-dependent activation of ERK1/2 may not be involved in the silica signaling pathway leading to NF-kappaB activation.
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Affiliation(s)
- Jihee Lee Kang
- Department of Physiology, Division of Cell Biology, Ewha Medical Research Center, Ewha Womans University College of Medicine, Seoul, Korea.
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16
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Gwinn MR, Vallyathan V. Respiratory burst: role in signal transduction in alveolar macrophages. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2006; 9:27-39. [PMID: 16393868 DOI: 10.1080/15287390500196081] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Alveolar macrophages play an important role in defense against airborne pathogens and particles. These macrophages respond through both the adaptive and acquired immune responses, and through the activation of a multitude of signaling pathways. One major macrophage defense mechanism is respiratory burst, the production of reactive oxygen species (ROS). While the ROS produced may act directly in pathogen killing, they may also be involved as secondary signaling messengers. This review focuses on the activation of four main signaling pathways following the production of reactive oxygen species. These pathways include the nuclear factor kappa beta (NFkB), activating protein-1 (AP-1), mitogen-activating protein kinase (MAPK), and phosphotidyl inositol-3 kinase (PI3K) pathways. This review also briefly examines the role of ROS in DNA damage, in particular looking at the base excision repair pathway (BER), the main pathway involved in repair of oxidative DNA damage. This review highlights many of the studies in the field of ROS, signal transduction, and DNA damage; however, work still remains to further elucidate the role of ROS in disease.
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Affiliation(s)
- Maureen R Gwinn
- Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA
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17
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Kang JL, Lee HW, Kim HJ, Lee HS, Castranova V, Lim CM, Koh Y. Inhibition of SRC tyrosine kinases suppresses activation of nuclear factor-kappaB, and serine and tyrosine phosphorylation of IkappaB-alpha in lipopolysaccharide-stimulated raw 264.7 macrophages. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2005; 68:1643-62. [PMID: 16195219 DOI: 10.1080/15287390500192114] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Involvement of protein tyrosine kinases (PTK) in lipopolysaccharide (LPS)-induced nuclear factor-kappa B (NF-kappaB) activation has been demonstrated. Studies investigated the role of PTK and the underlying mechanisms by which PTK play a role in LPS induction of pathways leading to NF-kappaB activation in macrophages. Inhibitors of PTK-genistein, herbimycin A, or AG126-blocked LPS-induced NF-kappaB activation. Genistein also blocked pervanadate-induced NF-kappaB activation. Furthermore, Src TK selective inhibitors-damnacanthal or PP1-blocked LPS-induced NF-kappaB activation over a range of nanomolar concentrations. Genistein, damnacanthal, or PP1 blocked the LPS-induced serine phosphorylation, the degradation of IkappaB-alpha, and the consequent translocation of the p65 subunit of NF-kappaB to the nucleus. In addition to serine phosphorylation of IkappaB-alpha, LPS-induced NF-kappaB activation also required tyrosine phosphorylation of IkappaB-alpha. These TK inhibitors blocked substantially LPS induction of tyrosine phosphorylation of IkappaB-alpha. Furthermore, cSrc and Lck were physically associated with IkappaB-alpha. These results suggest that the LPS-induced NF-kappaB pathways are dependent on both serine and tyrosine phosphorylation of IkappaB-alpha, and that Src TK, such as cSrc and Lck, are key components of the LPS signaling pathway through at least two different mechanisms associated with NF-kappaB activation.
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Affiliation(s)
- Jihee Lee Kang
- Department of Physiology, College of Medicine, Division of Cell Biology, Ewha Medical Research Center, Ewha Womans University, Seoul, Korea.
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18
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Jaramillo M, Godbout M, Olivier M. Hemozoin Induces Macrophage Chemokine Expression through Oxidative Stress-Dependent and -Independent Mechanisms. THE JOURNAL OF IMMUNOLOGY 2004; 174:475-84. [PMID: 15611273 DOI: 10.4049/jimmunol.174.1.475] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chemokine production has been associated with the immunopathology related to malaria. Previous findings indicated that hemozoin (HZ), a parasite metabolite released during schizogeny, might be an important source of these proinflammatory mediators. In this study we investigated the molecular mechanisms underlying HZ-inducible macrophage (Mphi) chemokine mRNA expression. We found that both Plasmodium falciparum HZ and synthetic HZ increase mRNA levels of various chemokine transcripts (MIP-1alpha/CCL3, MIP-1beta/CCL4, MIP-2/CXCL2, and MCP-1/CCL2) in murine B10R Mphi. The cellular response to HZ involved ERK1/2 phosphorylation, NF-kappaB activation, reactive oxygen species (ROS) generation, and ROS-dependent protein-tyrosine phosphatase down-regulation. Selective inhibition of either IkappaBalpha or the ERK1/2 pathway abolished both NF-kappaB activation and chemokine up-regulation. Similarly, blockage of HZ-inducible Mphi ROS with superoxide dismutase suppressed chemokine induction, strongly reduced NF-kappaB activation, and restored HZ-mediated Mphi protein-tyrosine phosphatase inactivation. In contrast, superoxide dismutase had no effect on EKR1/2 phosphorylation by HZ. Collectively, these data indicate that HZ triggers ROS-dependent and -independent signals, leading to increased chemokine mRNA expression in Mphi. Overall, our findings may help to better understand the molecular mechanisms through which parasite components, such as HZ, modulate the immune response during malaria infection.
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Affiliation(s)
- Maritza Jaramillo
- Research Institute of McGill University Health Center, Center for the Study of Host Resistance, Departments of Medicine, Microbiology, and Immunology, McGill University, 3775 University Street, Montréal, Québec, Canada H3A 2B4
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19
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Castranova V. Signaling pathways controlling the production of inflammatory mediators in response to crystalline silica exposure: role of reactive oxygen/nitrogen species. Free Radic Biol Med 2004; 37:916-25. [PMID: 15336307 DOI: 10.1016/j.freeradbiomed.2004.05.032] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Revised: 05/07/2004] [Accepted: 05/28/2004] [Indexed: 11/30/2022]
Abstract
Occupational exposure to crystalline silica has been linked to pulmonary fibrosis and lung cancer. Surface properties of crystalline silica are critical to the production of oxidant species, chemokines, inflammatory cytokines, and proliferative factors involved in the initiation and progression of silica-induced damage, inflammation, alveolar type II cell hyperplasia, fibroblast activation, and disease. The transcription factors nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) have been shown to play key roles in gene promotion for inflammatory mediators, oncogenes, and growth factors. This review summarizes evidence that in vitro and in vivo exposure to crystalline silica results in activation of NF-kappaB and AP-1. Signaling pathways for activation of these transcription factors are described. In addition, the role of silica-induced reactive oxygen species and nitric oxide in the activation of these signaling events is presented. Last, the generalizability of mechanisms regulating silica-induced pulmonary responses to pulmonary reactions to other occupational particles is discussed.
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Affiliation(s)
- Vincent Castranova
- National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA
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20
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O'Connor S, Shumway SD, Amanna IJ, Hayes CE, Miyamoto S. Regulation of constitutive p50/c-Rel activity via proteasome inhibitor-resistant IkappaBalpha degradation in B cells. Mol Cell Biol 2004; 24:4895-908. [PMID: 15143182 PMCID: PMC416427 DOI: 10.1128/mcb.24.11.4895-4908.2004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Constitutive NF-kappaB activity has emerged as an important cell survival component of physiological and pathological processes, including B-cell development. In B cells, constitutive NF-kappaB activity includes p50/c-Rel and p52/RelB heterodimers, both of which are critical for proper B-cell development. We previously reported that WEHI-231 B cells maintain constitutive p50/c-Rel activity via selective degradation of IkappaBalpha that is mediated by a proteasome inhibitor-resistant, now termed PIR, pathway. Here, we examined the mechanisms of PIR degradation by comparing it to the canonical pathway that involves IkappaB kinase-dependent phosphorylation and beta-TrCP-dependent ubiquitylation of the N-terminal signal response domain of IkappaBalpha. We found a distinct consensus sequence within this domain of IkappaBalpha for PIR degradation. Chimeric analyses of IkappaBalpha and IkappaBbeta further revealed that the ankyrin repeats of IkappaBalpha, but not IkappaBbeta, contained information necessary for PIR degradation, thereby explaining IkappaBalpha selectivity for the PIR pathway. Moreover, we found that PIR degradation of IkappaBalpha and constitutive p50/c-Rel activity in primary murine B cells were maintained in a manner different from B-cell-activating-factor-dependent p52/RelB regulation. Thus, our findings suggest that nonconventional PIR degradation of IkappaBalpha may play a physiological role in the development of B cells in vivo.
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Affiliation(s)
- Shelby O'Connor
- Department of Pharmacology, University of Wisconsin, 301 SMI, 1300 University Ave., Madison, WI 53706, USA
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21
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Chen F. Reactive Oxygen Species in the Activation and Regulation of Intracellular Signaling Events. OXYGEN/NITROGEN RADICALS 2004. [DOI: 10.1201/b14147-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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22
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Bohuslav J, Chen LF, Kwon H, Mu Y, Greene WC. p53 induces NF-kappaB activation by an IkappaB kinase-independent mechanism involving phosphorylation of p65 by ribosomal S6 kinase 1. J Biol Chem 2004; 279:26115-25. [PMID: 15073170 DOI: 10.1074/jbc.m313509200] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apoptosis induced by p53 has been proposed to involve activation of the transcription factor NF-kappaB. Here we describe the novel molecular mechanism through which p53 and DNA-damaging agents activate NF-kappaB. NF-kappaB induction by p53 does not occur through classical activation of the IkappaB kinases and degradation of IkappaBalpha. Rather, p53 expression stimulates the serine/threonine kinase ribosomal S6 kinase 1 (RSK1), which in turn phosphorylates the p65 subunit of NF-kappaB. The lower affinity of RSK1-phosphorylated p65 for its negative regulator, IkappaBalpha, decreases IkappaBalpha-mediated nuclear export of shuttling forms of NF-kappaB, thereby promoting the binding and action of NF-kappaB on cognate kappaB enhancers. These findings highlight a rather unusual pathway of NF-kappaB activation, which is utilized by the p53 tumor suppressor.
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Affiliation(s)
- Jan Bohuslav
- Gladstone Institute of Virology and Immunology and the Department of Medicine, University of California, San Francisco, California 94143-1234, USA
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23
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Liao CH, Sang S, Liang YC, Ho CT, Lin JK. Suppression of inducible nitric oxide synthase and cyclooxygenase-2 in downregulating nuclear factor-kappa B pathway by Garcinol. Mol Carcinog 2004; 41:140-9. [PMID: 15390082 DOI: 10.1002/mc.20050] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Garcinol is a polyisoprenylated benzophenone derivative of Garcinia indica fruit rind and other species. Recent studies have demonstrated that garcinol exhibited antioxidative effects in vitro. In this study, we found that garcinol inhibited the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-activated macrophages. Western blot analyzes and gel-shift assays revealed that garcinol strongly blocks the activation of eukaryotic transcription factor nuclear factor-kappa B (NF-kappa B)-induced by LPS. Moreover, transient transfection experiments showed that garcinol inhibited the NF-kappa B-dependent transcriptional activity. Based on these data, we demonstrated that inhibition of LPS-induced NF-kappa B activation occurred through suppressing the phosphorylation of I kappa B alpha and p38 mitogen-activated kinase (MAPK). Garcinol also lowers the LPS-induced increase of intracellular reactive oxygen species (ROS), which contributes to the activation of NF-kappa B. The NF-kappa B signaling pathway leads to inflammatory reaction and our results suggest that garcinol suppresses the expression of iNOS in this pathway.
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Affiliation(s)
- Chiung-Ho Liao
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 10018, Taiwan
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24
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Gopee NV, He Q, Sharma RP. Fumonisin B1-induced apoptosis is associated with delayed inhibition of protein kinase C, nuclear factor-kappaB and tumor necrosis factor alpha in LLC-PK1 cells. Chem Biol Interact 2003; 146:131-45. [PMID: 14597127 DOI: 10.1016/s0009-2797(03)00102-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Fumonisin B1 (FB1), the most potent of the fumonisin mycotoxins, is a carcinogen and causes a wide range of species-specific toxicoses. FB1 modulates the activity of protein kinase C (PKC), a family of phospholipid-dependent serine/threonine kinases that play important role in modulating a variety of biologic responses ranging from regulation of cell growth to cell death. Although it has been demonstrated that FB1 induces apoptosis in many cell lines, the precise mechanism of apoptosis is not fully understood. In this study, we investigated the membrane localization of various PKC isoforms, PKC enzyme activity, and its downstream targets, namely nuclear factor-kappa B (NF-kappaB), tumor necrosis factor alpha (TNFalpha), and caspase 3, in porcine renal epithelial (LLC-PK1) cells. FB1 repressed cytosol to membrane translocation of PKC-alpha, -delta, -epsilon, and -zeta isoforms over 24-72 h. The FB1-induced membrane PKC repression was corroborated by a concentration-dependent decrease in total PKC activity. Exposure of cells to phorbol 12-myristate 13-acetate (PMA) for this duration also resulted in repressed PKC membrane localization and activity comparable to FB1. Exposure of cells to FB1 (10 microM) was associated with inhibition of cytosol to nuclear translocation of NF-kappaB and NF-kappaB-DNA binding at 72 h. The expression of TNFalpha was significantly inhibited at 24 and 48 h in response to 1 and 10 microM FB1. Increased caspase 3 activity was observed in LLC-PK1 cells exposed to > or =1 microM FB1 at 48 h. PMA also increased the caspase 3 activity at 24 and 48 h. Results suggest that FB1-induced apoptosis involves the activation of caspase 3, which is associated with the repression of PKC and possibly its down-stream effectors, NF-kappaB and TNFalpha.
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Affiliation(s)
- Neera V Gopee
- Department of Physiology and Pharmacology, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602-7389, USA
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25
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Takada Y, Mukhopadhyay A, Kundu GC, Mahabeleshwar GH, Singh S, Aggarwal BB. Hydrogen peroxide activates NF-kappa B through tyrosine phosphorylation of I kappa B alpha and serine phosphorylation of p65: evidence for the involvement of I kappa B alpha kinase and Syk protein-tyrosine kinase. J Biol Chem 2003; 278:24233-41. [PMID: 12711606 DOI: 10.1074/jbc.m212389200] [Citation(s) in RCA: 392] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Although it is well established that reactive oxygen intermediates mediate the NF-kappaB activation induced by most agents, how H2O2 activates this transcription factor is not well understood. We found that treatment of human myeloid KBM-5 cells with H2O2 activated NF-kappaB in a dose- and time-dependent manner much as tumor necrosis factor (TNF) did but unlike TNF, H2O2 had no effect on IkappaBalpha degradation. Unexpectedly, however, like TNF-induced activation, H2O2-induced NF-kappaB activation was blocked by the calpain inhibitor N-Ac-Leu-Leu-norleucinal, suggesting that a proteosomal pathway was involved. Although H2O2 activated IkappaBalpha kinase, it did not induce the serine phosphorylation of IkappaBalpha. Like TNF, H2O2 induced the serine phosphorylation of the p65 subunit of NF-kappaB, leading to its nuclear translocation. We found that H2O2 induced the tyrosine phosphorylation of IkappaBalpha, which is needed for NF-kappaB activation. We present several lines of evidence to suggest that the Syk protein-tyrosine kinase is involved in H2O2-induced NF-kappaB activation. First, H2O2 activated Syk in KBM-5 cells; second, H2O2 failed to activate NF-kappaB in cells that do not express Syk protein; third, overexpression of Syk increased H2O2-induced NF-kappaB activation; and fourth, reduction of Syk transcription using small interfering RNA inhibited H2O2-induced NF-kappaB activation. We also showed that Syk induced the tyrosine phosphorylation of IkappaBalpha, which caused the dissociation, phosphorylation, and nuclear translocation of p65. Thus, overall, our results demonstrate that H2O2 induces NF-kappaB activation, not through serine phosphorylation or degradation of IkappaBalpha, but through Syk-mediated tyrosine phosphorylation of IkappaBalpha
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Affiliation(s)
- Yasunari Takada
- Department of Bioimmunotherapy, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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26
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Kang JL, Lee HS, Pack IS, Hur KC, Castranova V. Phosphoinositide 3-kinase activity leads to silica-induced NF-kappaB activation through interacting with tyrosine-phosphorylated I(kappa)B-alpha and contributing to tyrosine phosphorylation of p65 NF-kappaB. Mol Cell Biochem 2003; 248:17-24. [PMID: 12870650 DOI: 10.1023/a:1024163630166] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The role of the subunits of phosphoinositide (PI) 3-kinase in NF-kappaB activation in silica-stimulated RAW 264.7 cells was investigated. Results indicate that PI3-kinase activity was increased in response to silica. The p85alpha subunit of PI3-kinase interacted with tyrosine-phosphorylated I(kappa)B-alpha in silica-stimulated cells. PI3-kinase specific inhibitors, such as wortmannin and LY294003, substantially blocked both silica-induced PI3-kinase and NF-kappaB activation. The inhibition of NF-KB activation by PI3-kinase inhibitors was also observed in pervanadate-stimulated but not in LPS-stimulated cells. Furthermore, tyrosine phosphorylation of NF-kappaB p65 was enhanced in cells stimulated with silica, pervanadate or LPS, and wortmannin substantially inhibited the phosphorylation event induced by the first two stimulants but not LPS. Antioxidants, such as superoxide dismutase (SOD), N-acetylcysteine (NAC) and pyrrolidine dithiocarbamate (PDTC), blocked silica-induced PI3-kinase activation, suggesting that reactive oxygen species may be important regulatory molecules in NF-kappaB activation by mediating PI3-kinase activation. Our data suggest that p85 and p110 subunits of PI3-kinase play a role in NF-kappaB activation through interaction with tyrosine-phosphorylated I(kappa)B-alpha and contributing to tyrosine phosphorylation of p65 NF-kappaB.
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Affiliation(s)
- Jihee Lee Kang
- Department of Physiology, College of Medicine, Division of Cell Biology, Ewha Medical Research Center, Ewha Womans University, Seoul, Korea.
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27
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Abstract
Nuclear factor-kappaB (NF-kappaB) is a transcriptional factor that was originally discovered in the nucleus of B cells that bind to the kappa light chain of the immunoglobulins. Research during 15 years, however, has revealed that NF-kappaB is present in its inactive state in the cytoplasm of almost every cell type. When activated, NF-kappaB translocates to the nucleus, binds the DNA and regulates the expression of over 200 different genes. The product of these genes regulate the immune system, cell proliferation, tumor metastasis, inflammation and viral replication. Several tumor cell types express constitutively activated form of NF-kappaB and it is required for the proliferation of the tumor cells. Numerous studies have shown that Hodgkin's disease cells exhibit constitutive active NF-kappaB. The present review examines the mechanism how NF-kappaB is activated and its relevance to Hodgkin's disease.
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Affiliation(s)
- Anas Younes
- Department of Lymphoma/Myeloma, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 429 Houston, TX 77030, USA.
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28
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Hosoi T, Hirose R, Saegusa S, Ametani A, Kiuchi K, Kaminogawa S. Cytokine responses of human intestinal epithelial-like Caco-2 cells to the nonpathogenic bacterium Bacillus subtilis (natto). Int J Food Microbiol 2003; 82:255-64. [PMID: 12593928 DOI: 10.1016/s0168-1605(02)00311-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Intestinal epithelial cells produce cytokines in response to pathogenic bacteria. However, cellular responses of these cells to nonpathogenic strains, such as Bacillus subtilis, are yet to be determined. In this study, we investigate whether epithelial-like human colon carcinoma Caco-2 cells produce cytokines in response to B. subtilis or B. subtilis (natto). The latter strain is utilized for manufacturing the fermented soy food "natto". Live cells of nonpathogenic B. subtilis JCM 1465(T), B. subtilis (natto) and E. coli JCM 1649(T), as well as pathogenic S. enteritidis JCM 1652 and P. aeruginosa JCM 5516 strains, induced secretion of interleukin-6 (IL-6) and/or IL-8, but not IL-7, IL-15 or tumor necrosis factor alpha (TNF-alpha). Transepithelial electrical resistance (TER) of Caco-2 cell monolayers cultured with E. coli, S. enteritidis or P. aeruginosa decreased more rapidly than that of cells cultured with B. subtilis or B. subtilis (natto). The amounts of cytokine induced by B. subtilis (natto) cells were strain-dependent. Moreover, B. subtilis (natto) cells subjected to hydrochloric acid treatment, but not autoclaving, induced a higher secretion of IL-6 and IL-8 than intact cells. Tyrosine kinase inhibitors, including AG126 and genistein, suppressed cytokine secretion. Our results suggest that the nonpathogenic B. subtilis (natto) bacterium induces cytokine responses in intestinal epithelial cells via activation of an intracellular signaling pathway, such as that of nuclear factor-kappa B (NF-kappaB).
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Affiliation(s)
- Tomohiro Hosoi
- Tokyo Metropolitan Food Technology Research Center, 1-9 Kanda Sakuma-cho, Tokyo 101-0025, Chiyoda, Japan.
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29
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Abstract
Macrophages are key defenders of the lung and play an essential role in mediating the inflammatory response. Critical to this is the activation of the NADPH oxidase. Through receptor-mediated interactions, extracellular stimuli activate pathways that signal for the phosphorylation and assembly of the NADPH oxidase. Once the NADPH oxidase is activated, it produces superoxide and H2O2 in a process known as the respiratory burst. The involvement of O2.- and H2O2 in the antimicrobicidal function of macrophages has been assumed for many years, but it is now clear that the H2O2 produced by the respiratory burst functions as a second messenger and activates major signaling pathways in the alveolar macrophage. Both the nuclear factor-kappaB and activator protein-1 transcription factors are activated by H2O2 produced by the respiratory burst, and, since these control the inducible expression of genes whose products are part of the inflammatory response, this may be a critical link between the respiratory burst and other inflammatory responses. The c-Jun N-terminal kinase (JNK) and extracellular-regulated kinase (ERK) pathways, two members of the mitogen-activated protein kinase family, are also activated by the respiratory burst. JNK is activated by both exogenous and endogenously produced H2O2. Studies with ERK have shown that specific agonists of the respiratory burst, but not bolus H2O2, can activate this pathway. The ERK pathway also modulates the expression of genes via phosphorylation of the transcription factor Elk-1 that controls the production of the c-Fos transcription factor. Although an understanding of the mechanism of redox signaling is in its infancy, it is becoming clear that the reactive oxygen species produced by the respiratory burst have a profound effect on intracellular signaling pathways and ultimately in modulating gene expression.
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Affiliation(s)
- Karen E Iles
- Department of Environmental Health Sciences, School of Public Health, and Center for Free Radical Biology, University of Alabama at Birmingham, 35294-0022, USA
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30
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Forman HJ, Torres M. Reactive oxygen species and cell signaling: respiratory burst in macrophage signaling. Am J Respir Crit Care Med 2002; 166:S4-8. [PMID: 12471082 DOI: 10.1164/rccm.2206007] [Citation(s) in RCA: 620] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Phagocytes such as neutrophils and macrophages produce reactive oxygen species (ROS) during phagocytosis or stimulation with a wide variety of agents through activation of nicotinamide adenine dinucleotide phosphate reduced (NADPH) oxidase that is assembled at the plasma membrane from resident plasma membrane and cytosolic protein components. One of the subunits of the phagocyte NADPH oxidase is now recognized as a member of a family of NADPH oxidases, or NOX, present in cells other than phagocytes. Physiologic generation of ROS has been implicated in a variety of physiologic responses from transcriptional activation to cell proliferation and apoptosis. The increase in superoxide and hydrogen peroxide (H2O2) that results from stimulation of the NADPH oxidase is transient, in part due to the presence of the antioxidant enzymes, which return their concentrations to the prestimulation steady state level. Thus, the antioxidant enzymes may function in the "turn-off" phase of signal transduction by ROS. During its transient elevation, H2O2 may act as a modifier of key signaling enzymes through reversible oxidation of critical thiols. The rapid reaction of thiols with H2O2 when in their unprotonated state would provide a potential mechanism for the specificity that is necessary for physiologic cell signaling.
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Affiliation(s)
- Henry Jay Forman
- Department of Environmental Health Sciences, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama 35294,
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31
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Kanda N, Watanabe S. Substance P enhances the production of interferon-induced protein of 10 kDa by human keratinocytes in synergy with interferon-gamma. J Invest Dermatol 2002; 119:1290-7. [PMID: 12485430 DOI: 10.1046/j.1523-1747.2002.19626.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A neuropeptide substance P is related to skin inflammation. Interferon-induced protein of 10 kDa (IP-10) chemoattracts T helper 1 cells, and interferon-induced protein of 10 kDa production by keratinocytes is enhanced in inflammatory skin diseases such as psoriasis. We examined the in vitro effects of substance P on interferon-induced protein of 10 kDa production by human keratinocytes. Though substance P alone did not induce interferon-induced protein of 10 kDa production, it enhanced interferon-induced protein of 10 kDa secretion, mRNA expression, and promoter activity induced by suboptimal concentrations of interferon-gamma. Interferon-stimulated response element and two nuclear factor-kappaB sites on interferon-induced protein of 10 kDa promoter were responsible for the enhancement by substance P. Substance P alone enhanced transcriptional activity and transcription factor binding through the two nuclear factor-kappaB sites, whereas it did not alter interferon-gamma-induced transcriptional activity and transcription factor binding through interferon-stimulated response element. The effects of substance P on interferon-induced protein of 10 kDa production and nuclear factor-kappaB activation were inhibited by neurokinin-1 receptor antagonist, phospholipase C inhibitor, intracellular Ca2+ chelator, and anti-oxidant. These results suggest that substance P may induce nuclear factor-kappaB activation and interferon-induced protein of 10 kDa production in synergy with interferon-gamma via neurokinin-1 receptor on keratinocytes. These effects of substance P may be mediated via phospholipase C activation, intra-cellular Ca2+ signal, and reactive oxygen intermediates.
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Affiliation(s)
- Naoko Kanda
- Department of Dermatology, Teikyo University, School of Medicine, Tokyo, Japan.
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Lo AH, Liang YC, Lin-Shiau SY, Ho CT, Lin JK. Carnosol, an antioxidant in rosemary, suppresses inducible nitric oxide synthase through down-regulating nuclear factor-kappaB in mouse macrophages. Carcinogenesis 2002; 23:983-91. [PMID: 12082020 DOI: 10.1093/carcin/23.6.983] [Citation(s) in RCA: 179] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Carnosol is a naturally occurring phytopolyphenol found in rosemary. Carnosol functions as antioxidant and anticarcinogen. In the present study, we compared the antioxidant activity of carnosol and other compounds extracted from rosemary. Carnosol showed potent antioxidative activity in alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) free radicals scavenge and DNA protection from Fenton reaction. High concentrations of nitric oxide (NO) are produced by inducible NO synthase (iNOS) in inflammation and multiple stages of carcinogenesis. Treatment of mouse macrophage RAW 264.7 cell line with carnosol markly reduced lipopolysaccharide (LPS)-stimulated NO production in a concentration-related manner with an IC50 of 9.4 microM; but other tested compounds had slight effects. Western blot, reverse transcription-polymerase chain reaction, and northern blot analyses demonstrated that carnosol decreased LPS-induced iNOS mRNA and protein expression. Carnosol treatment showed reduction of nuclear factor-kappaB (NF-kappaB) subunits translocation and NF-kappaB DNA binding activity in activated macrophages. Carnosol also showed inhibition of iNOS and NF-kappaB promoter activity in transient transfection assay. These activities were referred to down-regulation of inhibitor kappaB (IkappaB) kinase (IKK) activity by carnosol (5 microM), thus inhibited LPS-induced phosphorylation as well as degradation of IkappaBalpha. Carnosol also inhibited LPS-induced p38 and p44/42 mitogen-activated protein kinase (MAPK) activation at a higher concentration (20 microM). These results suggest that carnosol suppresses the NO production and iNOS gene expression by inhibiting NF-kappaB activation, and provide possible mechanisms for its anti-inflammatory and chemopreventive action.
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Affiliation(s)
- Ai-Hsiang Lo
- Institute of Biochemistry, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, Taiwan
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Dai J, Xie C, Churg A. Iron loading makes a nonfibrogenic model air pollutant particle fibrogenic in rat tracheal explants. Am J Respir Cell Mol Biol 2002; 26:685-93. [PMID: 12034567 DOI: 10.1165/ajrcmb.26.6.4651] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
To examine the potential role of particle iron in fibrogenicity, we loaded nonfibrogenic fine (0.12micro) TiO(2) with increasing amounts of Fe(II)-Fe(III) chloride. Dusts were applied to rat tracheal explants, which were maintained in air organ culture for 1 wk. Iron-loaded dust increased procollagen gene expression and tissue hydroxyproline. The active oxygen species (AOS) scavenger tetramethylthiourea prevented these effects. Iron loading caused nuclear factor (NF)-kappaB activation, decreased levels of total IkappaBalpha, but relatively increased levels of both IkappaBalpha-phosphoserine 32/36 and IkappaBalpha-phosphotyrosine. A citrate extract of iron-loaded dust increased procollagen expression. Gel shift using a probe consisting of the NF-kappaB consensus sequence from the prolyl-4-hydroxylase promoter and adjacent bases showed increased nuclear binding, and RT-PCR examination showed increased prolyl-hydroxylase alpha-chain gene expression after iron loading. We conclude that addition of surface iron can convert a nonreactive model air pollutant particle into a fibrogenic particle via AOS- and NF-kappaB-dependent pathways, probably through two different NF-kappaB activation pathways in two different anatomic compartments. This process may proceed in vivo through iron extracted from the dust into the cytoplasm. NF-kappaB activation may directly increase expression of prolyl hydroxylase, an enzyme involved in collagen synthesis. These findings suggest that air pollutant particles containing significant quantities of transition metals may produce airway wall fibrosis and lead to chronic obstructive pulmonary disease.
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Affiliation(s)
- Jin Dai
- Department of Pathology, University of British Columbia, Vancouver, Canada
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34
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Kang JL, Pack IS, Hong SM, Lee HS, Hah JS, Nam W, Leonard S, Castranova V. Zinc tetrakis(N-methyl-4'-pyridyl) porphyrinato is an effective inhibitor of stimulant-induced activation of RAW 264.7 cells. Toxicol Appl Pharmacol 2001; 172:140-9. [PMID: 11298500 DOI: 10.1006/taap.2001.9144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One proposed mechanism for the development of silica-induced fibrosis is prolonged pulmonary inflammation and lung damage resulting from the secretion of reactive mediators from alveolar macrophages. Metalloporphyrins have antioxidative and antiinflammatory activities. However, the molecular basis for the antiinflammatory action of zinc tetrakis(N-methyl-4'-pyridyl) porphyrinato (ZnTMPyP) has not been elucidated. The objective of this study was to determine whether ZnTMPyP exhibited the ability to inhibit the production of reactive oxygen species (ROS), the activation of NF-kappaB, or the secretion of IL-1 in RAW 264.7 cells, and whether such inhibitory activity was related to the ROS-scavenging ability of ZnTMPyP. The results indicate that, although ZnTMPyP is not cytotoxic to RAW 264.7 cells, it is a potent inhibitor in ROS production by RAW 264.7 cells in response to various stimulants, such as silica, zymosan, or phorbol myristate acetate. ZnTMPyP is also effective in reducing stimulant-induced DNA-binding activity of NF-kappaB and silica-induced tyrosine phosphorylation of IkappaB-alpha. ZnTMPyP also inhibits LPS-induced IL-1 production. However, ZnTMPyP exhibits relatively weak ability to directly scavenge hyroxyl or superoxide radicals. On the basis of effective concentrations of ZnTMPyP, these results suggest that ZnTMPyP directly acts as an inhibitor of cellular activation in addition to exhibiting an antioxidant effect. Therefore, it is suggested that further studies concerning the effects of ZnTMPyP using in vivo oxidative stress models or its effects on the cytotoxic process of human diseases associated with lung inflammation and injury are warranted. In addition, ZnTMPyP may be a useful tool to investigate the molecular mechanisms involved in stimulant-induced signal pathways.
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Affiliation(s)
- J L Kang
- Department of Physiology, College of Medicine, Ewha Woman's University Medical Research Center, 911-1 Mok-6-dong, Yangcheon-ku, Seoul, 158-056, Korea.
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