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Ding M, Zhang C, Wang W, Wang P, Pei Y, Wang N, Huang S, Hao C, Yao W. Silica-exposed macrophages-secreted exosomal miR125a-5p induces Th1/Th2 and Treg/Th17 cell imbalance and promotes fibroblast transdifferentiation. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 267:115647. [PMID: 37918332 DOI: 10.1016/j.ecoenv.2023.115647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/22/2023] [Accepted: 10/27/2023] [Indexed: 11/04/2023]
Abstract
Until now, the specific pathogenesis of silicosis is not clear. Exosomal miRNAs, as a newly discovered intercellular communication medium, play an important role in many diseases. Our previous research found that serum exosomal miR125a-5p was increased in silicosis patients by miRNAs high-throughput sequencing. TRAF6, is a target gene of miR125a-5p, which is involved in T-cell differentiation. Furthermore, results from animal study indicate that knockdown of miR-125a-5p can regulate T lymphocyte subsets and significantly reduce pulmonary fibrosis by targeting TRAF6. However, the level of serum exosomal miR125a-5p in silicosis patients has not been reported, the role of macrophages-secreted exosomal miR-125a-5p in regulating T cell differentiation to promote fibroblast transdifferentiation (FMT) remains unknown. In this study, the levels of serum exosomal miR125a-5p and serum TGF-β1, IL-17A, IL-4 cytokines in silicosis patients were elevated, with the progression of silicosis, the level of serum exosomal miR125a-5p and serum IL-4 were increased; thus, the serum level of IFN-γ was negatively correlated with the progression of silicosis. In vitro, the levels of miR125a-5p in macrophages, exosomes, and T cells stimulated by silica were significantly increased. When the mimic was transfected into T cells, which directly suppressed TRAF6 and caused the imbalance of T cells differentiation, induced FMT. To sum up, these results indicate that exosomal miR-125a-5p may by targeting TRAF6 of T cells, induces the activation and apoptosis of T cells and the remodeling of Th1/Th2 and Th17/Tregs distribution, ultimately promotes FMT. Suggesting that exosomal miR-125a-5p may be a potential therapeutic target for silicosis.
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Affiliation(s)
- Mingcui Ding
- Department of Nosocomial Infection Control, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou 450003, Henan, China
| | - Chengpeng Zhang
- Department of Occupational Health and Occupational Disease, School of Public Health, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Wei Wang
- Department of Occupational Health and Occupational Disease, School of Public Health, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Pengpeng Wang
- Key Laboratory of Public Health Safety, Ministry of Education, School of Public Health, Fudan University, Shanghai 200032, China
| | - Yangqing Pei
- Department of Clinical Laboratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Na Wang
- Department of Occupational Health and Occupational Disease, School of Public Health, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Shan Huang
- Henan Institute of Food and Salt Industry Inspection Technology, Zhengzhou 450001, Henan, China
| | - Changfu Hao
- Department of child and Adolecence health, School of public health, Zhengzhou University, Zhengzhou 450001, Henan, China.
| | - Wu Yao
- Department of Occupational Health and Occupational Disease, School of Public Health, Zhengzhou University, Zhengzhou 450001, Henan, China.
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Ganesan N, Ronsmans S, Hoet P. Differential immunological effects of silica nanoparticles on peripheral blood mononuclear cells of silicosis patients and controls. Front Immunol 2022; 13:1025028. [PMID: 36311760 PMCID: PMC9606771 DOI: 10.3389/fimmu.2022.1025028] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 09/21/2022] [Indexed: 11/29/2022] Open
Abstract
Silicosis is a fibrotic disease caused by the inhalation of respirable silica particles, which are typically engulfed by alveolar macrophages and subsequently induce the release of inflammatory cytokines. Various animal experimental and human studies have focused on modeling silicosis, to assess the interactions of macrophages and other cell types with silica particles. There is still, however, limited knowledge on the differential response upon silica-exposure between silicosis patients and controls. We focused on studying the responsiveness of peripheral blood mononuclear cells (PBMCs) to silica nanoparticles (SiNPs) - Ludox and NM-200 - of silicosis patients and controls. The proliferative capacity of T- CD3+ and B- CD19+ cells, were evaluated via Carboxyfluorescein succinimidyl ester (CFSE) assay. The activation status of lymphocyte subsets and response to silica were also evaluated by comparing the extent of micro-granuloma or aggregate formation with the cytokine secretion profiles between both groups of individuals. The proliferative capacity of CD19+ cells was elevated in silicotic patients as opposed to controls. Subsets of regulatory T cells (CD4+ CD25+ and CD8+ CD25+) and immunoglobulins IgM and IgG were also significantly increased in patients. The number and the size of aggregates formed were higher with SiNPs stimulation in patients compared to controls. Multivariable analysis also elucidated the role of key cytokines like interleukin-1β (IL-1β), IL-6 and interferon-gamma (IFN-γ), which were upregulated in SiNP-stimulated PBMCs of patients compared to controls. Our ex vivo model thus has potential to provide insights into the immunological effects of silica particles in lymphocytes of silicosis patients and controls.
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Affiliation(s)
- Nirosha Ganesan
- Laboratory of Toxicology, Unit of Environment & Health, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium
- Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), KU Leuven, Leuven, Belgium
| | - Steven Ronsmans
- Laboratory of Toxicology, Unit of Environment & Health, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium
- Clinic for Occupational and Environmental Medicine, Department of Respiratory Diseases, University Hospitals Leuven, Leuven, Belgium
| | - Peter Hoet
- Laboratory of Toxicology, Unit of Environment & Health, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium
- Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), KU Leuven, Leuven, Belgium
- *Correspondence: Peter Hoet,
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Yu Y, Liu Y, Yao L, Shen Y, Sun Q, Sha W. Factors Influencing False-Negative Results of QuantiFERON-TB Gold In-Tube (QFT-GIT) in Active Tuberculosis and the Desirability of Resetting Cutoffs for Different Populations: A Retrospective Study. Trop Med Infect Dis 2022; 7:tropicalmed7100278. [PMID: 36288019 PMCID: PMC9607193 DOI: 10.3390/tropicalmed7100278] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/20/2022] [Accepted: 09/26/2022] [Indexed: 11/07/2022] Open
Abstract
Objectives The value of QuantiFERON-TB Gold In-Tube (QFT-GIT) in the diagnosis of TB varies by population, comorbidities, and other factors. In this study, we aimed to investigate factors that influence false-negative results of QFT-GIT test in the diagnosis of TB as well as the impact of different cutoffs on the diagnostic value. Methods A total of 3562 patients who underwent QFT-GIT tests at Shanghai Pulmonary Hospital were enrolled retrospectively between May 2016 and May 2017. False-negative and false-positive results were analyzed using different clinical stratifications. The optimal cutoff values were established under different clinical conditions. Results Positive QFT-GIT results greatly shortened the time taken to diagnose smear-negative TB. The factors of age, smear and culture results, site of TB, comorbidity with tumors, white blood cell count, neutrophil count, and CD4/CD8 ratio were significantly correlated with false-negative QFT-GIT results (p < 0.05). Personalized cutoff values were established according to different influencing factors. The results showed high consistency between the smear-negative and total populations. Conclusion QFT-GIT can facilitate the early diagnosis of smear-negative TB. The diagnostic performance of the QFT-GIT test in the diagnosis of active TB was shown to be affected by many clinical factors. Personalized cutoff values may have superior value in the identification of active tuberculosis under different conditions.
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Affiliation(s)
- Yuanyuan Yu
- Department of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
- Clinical and Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
| | - Yidian Liu
- Department of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
- Clinical and Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
| | - Lan Yao
- Department of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
- Clinical and Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
| | - Yanheng Shen
- Department of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
- Clinical and Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
| | - Qin Sun
- Department of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
- Clinical and Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
- Correspondence: (Q.S.); (W.S.)
| | - Wei Sha
- Department of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
- Clinical and Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
- Correspondence: (Q.S.); (W.S.)
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Comparison of Silicosis and Tuberculosis Involving Mediastinal Lymph Nodes Based on Contrast-Enhanced Multidetector-Row Computed Tomography. Lung 2022; 200:261-268. [PMID: 35290523 DOI: 10.1007/s00408-022-00522-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 02/22/2022] [Indexed: 02/05/2023]
Abstract
PURPOSE To investigate the different imaging features of contrast-enhanced multidetector-row-computed tomography (MDCT) for distinguishing between silicosis and tuberculosis involving the mediastinal lymph nodes. METHODS 86 silicosis patients and 61 tuberculosis patients with mediastinal lymphadenopathy based on contrast-enhanced MDCT were included. The enhanced patterns, anatomical distribution and calcification features of the enlarged lymph nodes were retrospectively compared between the groups using the Pearson chi-square test or Fisher's exact test. RESULTS Homogeneous enhancement of the mediastinal lymph nodes was more commonly observed in silicosis (94.2%, 81/86) than in tuberculosis (19.7%, 12/61). Peripheral enhancement was more frequent in tuberculosis (n = 44, 72.1%) than in silicosis involving the mediastinal lymph nodes (n = 1, 1.2%), and multilocular appearance was more frequent in TB than in silicosis. Tuberculosis was more likely to affect regions 1R, 2R, 2L, 3A, 5 and 6 than silicosis (all p < 0.05), especially region 2R. Calcification of the lymph nodes was more common in the silicosis group than in tuberculosis group. The sensitivity, specificity, and accuracy of silicosis with lymphadenopathy with homogeneous enhanced pattern were 94.2%, 80.3% and 88.4%, respectively. The sensitivity, specificity, and accuracy of tuberculosis lymphadenopathy with peripheral enhanced pattern were 72.1%, 98.8%, and 87.7%, respectively. CONCLUSION The predominant enhanced patterns, anatomical distribution, and calcification features of mediastinal lymph nodes were different between tuberculosis and silicosis. These radiographic features might help differentiate tuberculosis from silicosis, which provides imaging information for the differential diagnosis of the two diseases in a clinical setting.
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Dihydrotanshinone I Alleviates Crystalline Silica-Induced Pulmonary Inflammation by Regulation of the Th Immune Response and Inhibition of STAT1/STAT3. Mediators Inflamm 2019; 2019:3427053. [PMID: 31379467 PMCID: PMC6652093 DOI: 10.1155/2019/3427053] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/11/2019] [Indexed: 12/15/2022] Open
Abstract
Occupational exposure to crystalline silica (CS) results in a persistent pulmonary inflammatory response that eventually leads to abnormal tissue repair, disability, and death. The inflammatory-immune responses occur in the early stages of CS exposure, and both innate and adaptive immunity are involved. CD4+ T cells play a pivotal role in the pathogenesis of CS-induced pulmonary disease, which has no proven curative therapy. Dihydrotanshinone I (DHI), a natural product isolated from Salvia miltiorrhiza Bunge (Danshen), has anti-inflammatory and immunomodulatory properties. However, whether DHI has a protective effect on CS-induced lung disease, how it influences the Th immune response, and the potential underlying molecular mechanism(s) have not been fully clarified. In this study, DHI treatment of CS-exposed mice reduced the expression of proinflammatory cytokines and the infiltration of immune cells. It significantly ameliorated CS-induced pulmonary inflammation by attenuating T helper (Th)1 and Th17 responses, which were tightly related to the inhibition of STAT1 and STAT3. DHI significantly altered Th2 cytokines but not the Th2 nuclear transcription factor. Furthermore, our study found that DHI treatment also affected regulatory T cell activity in CS-injured mice. Taken together, our findings indicated that DHI could modulate Th responses and alleviate CS-induced pulmonary inflammation, suggesting a novel application of DHI in CS-induced pulmonary disease.
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Konečný P, Ehrlich R, Gulumian M, Jacobs M. Immunity to the Dual Threat of Silica Exposure and Mycobacterium tuberculosis. Front Immunol 2019; 9:3069. [PMID: 30687311 PMCID: PMC6334662 DOI: 10.3389/fimmu.2018.03069] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 12/11/2018] [Indexed: 01/28/2023] Open
Abstract
Exposure to silica and the consequent development of silicosis are well-known health problems in countries with mining and other dust producing industries. Apart from its direct fibrotic effect on lung tissue, chronic and immunomodulatory character of silica causes susceptibility to tuberculosis (TB) leading to a significantly higher TB incidence in silica-exposed populations. The presence of silica particles in the lung and silicosis may facilitate initiation of tuberculous infection and progression to active TB, and exacerbate the course and outcome of TB, including prognosis and survival. However, the exact mechanisms of the involvement of silica in the pathological processes during mycobacterial infection are not yet fully understood. In this review, we focus on the host's immunological response to both silica and Mycobacterium tuberculosis, on agents of innate and adaptive immunity, and particularly on silica-induced immunological modifications in co-exposure that influence disease pathogenesis. We review what is known about the impact of silica and Mycobacterium tuberculosis or their co-exposure on the host's immune system, especially an impact that goes beyond an exclusive focus on macrophages as the first line of the defense. In both silicosis and TB, acquired immunity plays a major role in the restriction and/or elimination of pathogenic agents. Further research is needed to determine the effects of silica in adaptive immunity and in the pathogenesis of TB.
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Affiliation(s)
- Petr Konečný
- Centre for Environmental and Occupational Health, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa.,Division of Immunology, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Rodney Ehrlich
- Centre for Environmental and Occupational Health, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Mary Gulumian
- National Health Laboratory Service, Department of Toxicology and Biochemistry, National Institute for Occupational Health, Johannesburg, South Africa.,Division of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa.,National Health Laboratory Service, Johannesburg, South Africa
| | - Muazzam Jacobs
- Division of Immunology, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,National Health Laboratory Service, Johannesburg, South Africa.,Immunology of Infectious Disease Research Unit, South African Medical Research Council, Cape Town, South Africa
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Schweitzer MD, Calzadilla AS, Salamo O, Sharifi A, Kumar N, Holt G, Campos M, Mirsaeidi M. Lung health in era of climate change and dust storms. ENVIRONMENTAL RESEARCH 2018; 163:36-42. [PMID: 29426026 DOI: 10.1016/j.envres.2018.02.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 01/29/2018] [Accepted: 02/02/2018] [Indexed: 05/04/2023]
Abstract
Dust storms are strong winds which lead to particle exposure over extensive areas. These storms influence air quality on both a local and global scale which lead to both short and long-term effects. The frequency of dust storms has been on the rise during the last decade. Forecasts suggest that their incidence will increase as a response to the effects of climate change and anthropogenic activities. Elderly people, young children, and individuals with chronic cardiopulmonary diseases are at the greatest risk for health effects of dust storms. A wide variety of infectious and non-infectious diseases have been associated with dust exposure. Influenza A virus, pulmonary coccidioidomycosis, bacterial pneumonia, and meningococcal meningitis are a few examples of dust-related infectious diseases. Among non-infectious diseases, chronic obstructive pulmonary disease, asthma, sarcoidosis and pulmonary fibrosis have been associated with dust contact. Here, we review two molecular mechanisms of dust induced lung disease for asthma and sarcoidosis. We can also then further understand the mechanisms by which dust particles disturb airway epithelial and immune cells.
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Affiliation(s)
- Michael D Schweitzer
- Division of Pulmonary and Critical Care, University of Miami, Miami, FL, United States
| | | | - Oriana Salamo
- Division of Pulmonary and Critical Care, University of Miami, Miami, FL, United States
| | - Arash Sharifi
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
| | - Naresh Kumar
- Department of Public Health Sciences, University of Miami, Miami, FL, United States
| | - Gregory Holt
- Division of Pulmonary and Critical Care, University of Miami, Miami, FL, United States; Miami VA Healthcare System, Miami, FL, United States
| | - Michael Campos
- Division of Pulmonary and Critical Care, University of Miami, Miami, FL, United States; Miami VA Healthcare System, Miami, FL, United States
| | - Mehdi Mirsaeidi
- Division of Pulmonary and Critical Care, University of Miami, Miami, FL, United States; Miami VA Healthcare System, Miami, FL, United States.
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Carneiro PJ, Clevelario AL, Padilha GA, Silva JD, Kitoko JZ, Olsen PC, Capelozzi VL, Rocco PRM, Cruz FF. Bosutinib Therapy Ameliorates Lung Inflammation and Fibrosis in Experimental Silicosis. Front Physiol 2017; 8:159. [PMID: 28360865 PMCID: PMC5350127 DOI: 10.3389/fphys.2017.00159] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/01/2017] [Indexed: 12/16/2022] Open
Abstract
Silicosis is an occupational lung disease for which no effective therapy exists. We hypothesized that bosutinib, a tyrosine kinase inhibitor, might ameliorate inflammatory responses, attenuate pulmonary fibrosis, and thus improve lung function in experimental silicosis. For this purpose, we investigated the potential efficacy of bosutinib in the treatment of experimental silicosis induced in C57BL/6 mice by intratracheal administration of silica particles. After 15 days, once disease was established, animals were randomly assigned to receive DMSO or bosutinib (1 mg/kg/dose in 0.1 mL 1% DMSO) by oral gavage, twice daily for 14 days. On day 30, lung mechanics and morphometry, total and differential cell count in alveolar septa and granuloma, levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, IL-4, transforming growth factor (TGF)-β, and vascular endothelial growth factor in lung homogenate, M1 and M2 macrophages, total leukocytes, and T cells in BALF, lymph nodes, and thymus, and collagen fiber content in alveolar septa and granuloma were analyzed. In a separate in vitro experiment, RAW264.7 macrophages were exposed to silica particles in the presence or absence of bosutinib. After 24 h, gene expressions of arginase-1, IL-10, IL-12, inducible nitric oxide synthase (iNOS), metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinase (TIMP)-1, and caspase-3 were evaluated. In vivo, in silicotic animals, bosutinib, compared to DMSO, decreased: (1) fraction area of collapsed alveoli, (2) size and number of granulomas, and mononuclear cell granuloma infiltration; (3) IL-1β, TNF-α, IFN-γ, and TGF-β levels in lung homogenates, (4) collagen fiber content in lung parenchyma, and (5) viscoelastic pressure and static lung elastance. Bosutinib also reduced M1 cell counts while increasing M2 macrophage population in both lung parenchyma and granulomas. Total leukocyte, regulatory T, CD4+, and CD8+ cell counts in the lung-draining lymph nodes also decreased with bosutinib therapy without affecting thymus cellularity. In vitro, bosutinib led to a decrease in IL-12 and iNOS and increase in IL-10, arginase-1, MMP-9, and TIMP-1. In conclusion, in the current model of silicosis, bosutinib therapy yielded beneficial effects on lung inflammation and remodeling, therefore resulting in lung mechanics improvement. Bosutinib may hold promise for silicosis; however, further studies are required.
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Affiliation(s)
- Priscila J Carneiro
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Amanda L Clevelario
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Gisele A Padilha
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Johnatas D Silva
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Jamil Z Kitoko
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Laboratory of Clinical Bacteriology and Immunology, Department of Toxicological and Clinical Analysis, School of Pharmacy, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Priscilla C Olsen
- Laboratory of Clinical Bacteriology and Immunology, Department of Toxicological and Clinical Analysis, School of Pharmacy, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Vera L Capelozzi
- Laboratory of Pulmonary Genomics, Department of Pathology, School of Medicine, University of São Paulo São Paulo, Brazil
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Fernanda F Cruz
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
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Liu F, Dai W, Li C, Lu X, Chen Y, Weng D, Chen J. Role of IL-10-producing regulatory B cells in modulating T-helper cell immune responses during silica-induced lung inflammation and fibrosis. Sci Rep 2016; 6:28911. [PMID: 27354007 PMCID: PMC4926212 DOI: 10.1038/srep28911] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 06/13/2016] [Indexed: 12/18/2022] Open
Abstract
Silicosis is characterized by chronic lung inflammation and fibrosis, which are seriously harmful to human health. Previous research demonstrated that uncontrolled T-helper (Th) cell immune responses were involved in the pathogenesis of silicosis. Lymphocytes also are reported to have important roles. Existing studies on lymphocyte regulation of Th immune responses were limited to T cells, such as the regulatory T (Treg) cell, which could negatively regulate inflammation and promote the process of silicosis. However, other regulatory subsets in silicosis have not been investigated in detail, and the mechanism of immune homeostasis modulation needs further exploration. Another regulatory lymphocyte, the regulatory B cell, has recently drawn increasing attention. In this study, we comprehensively showed the role of IL-10-producing regulatory B cell (B10) in a silicosis model of mice. B10 was inducible by silica instillation. Insufficient B10 amplified inflammation and attenuated lung fibrosis by promoting the Th1 immune response. Insufficient B10 clearly inhibited Treg and decreased the level of IL-10. Our study indicated that B10 could control lung inflammation and exacerbate lung fibrosis by inhibiting Th1 response and modulating the Th balance. The regulatory function of B10 could be associated with Treg induction and IL-10 secretion.
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Affiliation(s)
- Fangwei Liu
- Division of Pneumoconiosis, School of Public Health, China Medical University, Shenyang, P. R. China
| | - Wujing Dai
- Division of Pneumoconiosis, School of Public Health, China Medical University, Shenyang, P. R. China
| | - Chao Li
- Division of Pneumoconiosis, School of Public Health, China Medical University, Shenyang, P. R. China
| | - Xiaowei Lu
- Division of Pneumoconiosis, School of Public Health, China Medical University, Shenyang, P. R. China
| | - Ying Chen
- Division of Pneumoconiosis, School of Public Health, China Medical University, Shenyang, P. R. China
| | - Dong Weng
- Department of Respiratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, P. R. China
| | - Jie Chen
- Division of Pneumoconiosis, School of Public Health, China Medical University, Shenyang, P. R. China
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Blockade of Wnt/β-Catenin Pathway Aggravated Silica-Induced Lung Inflammation through Tregs Regulation on Th Immune Responses. Mediators Inflamm 2016; 2016:6235614. [PMID: 27069316 PMCID: PMC4812397 DOI: 10.1155/2016/6235614] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/13/2016] [Accepted: 02/15/2016] [Indexed: 12/31/2022] Open
Abstract
CD4+ T cells play an important role in regulating silica-induced inflammation and fibrosis. Recent studies showed that Wnt/β-catenin pathway could modulate the function and the differentiation of CD4+ T cells. Therefore, Wnt/β-catenin pathway may participate in the development and progress of silicosis. To investigate the role of Wnt/β-catenin pathway, we used lentivirus expressing β-catenin shRNA to block the Wnt/β-catenin pathway by intratracheal instillation to the mice model of silicosis. Treatment of lentivirus could significantly aggravate the silica-induced lung inflammation and attenuated the fibrosis at the late stage. By analyzing CD4+ T cells, we found that blockade of Wnt/β-catenin pathway suppressed regulatory T cells (Tregs). Reciprocally, enhanced Th17 response was responsible for the further accumulation of neutrophils and production of proinflammatory cytokines. In addition, blockade of Wnt/β-catenin pathway delayed the Th1/Th2 polarization by inhibiting Tregs and Th2 response. These results indicated that Wnt/β-catenin pathway could regulate Tregs to modulate Th immune response, which finally altered the pathological character of silicosis. Our study suggested that Wnt/β-catenin pathway might be a potential target to treat the silica-induced inflammation and fibrosis.
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Yıldızgören MT, Öziş TN, Baki AE, Tutkun E, Yılmaz H, Tiftik T, Ekiz T, Özgirgin N. Evaluation of bone mineral density and 25-hydroxyvitamin D levels in subjects with silica exposure. Environ Health Prev Med 2016; 21:149-53. [PMID: 26825971 DOI: 10.1007/s12199-016-0509-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 01/12/2016] [Indexed: 10/22/2022] Open
Abstract
OBJECTIVE The purpose of the study was to evaluate the bone mineral density (BMD) and 25-hydroxyvitamin D (25(OH)D) levels in patients with silica exposure. MATERIALS AND METHODS The study included 104 male subjects with silica exposure and 36 healthy subjects. Posterior-anterior radiographs were classified according to the International Labour Office (ILO) Classification. Category 0 patients were classified as Group I (n = 54), category I patients were classified as Group II (n = 25), Category II and III patients were classified as Group III (n = 25). RESULTS Femoral neck BMD values were significantly lower in Group III (p = 0.007). Lumbar vertebrae BMD values were significantly lower in all groups with silica exposure than in the control group (p = 0.000). The osteoporosis rate was significantly higher in Group III (p = 0.000). Subjects with silica exposure were determined to have diminished 25(OH)D levels (p = 0.012). CONCLUSION The results of this study demonstrated that subjects with silica exposure have diminished BMD and 25(OH)D levels.
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Affiliation(s)
- Mustafa Turgut Yıldızgören
- Department of Physical Medicine and Rehabilitation, Ankara Occupational Diseases Hospital, Ankara, Turkey.
| | - Türkan Nadir Öziş
- Department of Chest Diseases, Ankara Occupational Diseases Hospital, Ankara, Turkey
| | - Ali Erdem Baki
- Department of Physical Medicine and Rehabilitation, Ankara Occupational Diseases Hospital, Ankara, Turkey
| | - Engin Tutkun
- Department of Toxicology, Ankara Occupational Diseases Hospital, Ankara, Turkey
| | - Hınç Yılmaz
- Department of Toxicology, Ankara Occupational Diseases Hospital, Ankara, Turkey
| | - Tülay Tiftik
- Department of Physical Medicine and Rehabilitation, Ankara Physical Medicine and Rehabilitation Training and Research Hospital, Ankara, Turkey
| | - Timur Ekiz
- Department of Physical Medicine and Rehabilitation, Ankara Physical Medicine and Rehabilitation Training and Research Hospital, Ankara, Turkey
| | - Neşe Özgirgin
- Department of Physical Medicine and Rehabilitation, Ankara Physical Medicine and Rehabilitation Training and Research Hospital, Ankara, Turkey
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Reduction of IL-17A might suppress the Th1 response and promote the Th2 response by boosting the function of Treg cells during silica-induced inflammatory response in vitro. Mediators Inflamm 2014; 2014:570894. [PMID: 24692850 PMCID: PMC3945471 DOI: 10.1155/2014/570894] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/30/2013] [Accepted: 01/03/2014] [Indexed: 02/07/2023] Open
Abstract
Silica inhalation can induce chronic lung inflammation and fibrosis. Upon silica stimulation, activated macrophages trigger the T-lymphocyte which can differentiate into many different types of Th cells, including the recently discovered Th17 cells. IL-17A, the typical Th17 cytokine, is reported in some inflammatory diseases. However, the role of IL-17A in silica-induced inflammatory response is still not clear. The regulatory mechanism of silica-induced Th17 response also needs to be investigated. So we established a mice primary cell coculture system (macrophage and lymphocyte) to investigate the role of IL-17A in silica-induced inflammatory response in vitro, by using anti-IL-17A mAb and IL-1Ra. Both anti-IL-17A mAb and IL-1Ra decreased the level of IL-17A and increased the function of Treg cells. The Th1 response was suppressed and the Th2 response was promoted by the addition of anti-IL-17A mAb or IL-1Ra. IL-1Ra treatment decreased the level of IL-6, whereas the levels of IL-23 and ROR- γ t were increased. Our study demonstrated that IL-17A reduction altered the pattern of silica-induced Th responses by boosting the function of Treg cells in vitro. Blocking the function of IL-1 signal pathway could suppress the level of IL-17A, which played the major role in modulating silica-induced Th responses in vitro.
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13
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Arens AM, Barr B, Puchalski SM, Poppenga R, Kulin RM, Anderson J, Stover SM. Osteoporosis associated with pulmonary silicosis in an equine bone fragility syndrome. Vet Pathol 2010; 48:593-615. [PMID: 21097716 DOI: 10.1177/0300985810385151] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
California horses incur a bone fragility syndrome manifested by pathologic fractures. This study investigated gross, radiographic, and histologic features of the disorder as well as relationships with silicosis and levels of heavy metals and trace minerals through a postmortem study of 9 affected and 3 unaffected horses. Bones and soft tissues were evaluated grossly and histologically. Bones, lymph nodes, and lung tissue were evaluated radiographically. Tissues were evaluated for silicon levels, intracytoplasmic crystals, heavy metals, and trace minerals. All 9 affected horses had osteoporosis and clinical or subclinical pulmonary disease due to silicosis (8/9) or pneumoconiosis (1/9). All affected horses had radiographic findings consistent with osteopenia and histologic evidence of osteoporosis characterized by osteopenia, numerous resorption cavities, cement lines, and a mosaic lamellar pattern indicative of multiple remodeling events. Silicosis was characterized by widespread pulmonary granuloma formation with fibrosis; variable tracheobronchiolar and mediastinal granulomatous lymphadenitis; intracellular crystals within lung and lymph node macrophages; and pronounced lymph node fibrosis, focal necrosis, and dystrophic calcification. Crystals in lung (6/9) and lymph node (8/9) tissues were identified as cytotoxic silica dioxide polymorphs. Lung and liver tissue from affected horses had elevated levels of elemental silicon. Osteoporosis was highly correlated (r = 0.8, P < .01) with silicosis. No abnormalities in heavy metal or trace minerals were detected. This evaluation indicated that horses with bone fragility disorder have systemic osteoporosis associated with fibrosing pulmonary silicosis. The etiopathogenesis of the bone fragility syndrome is unknown; however, this study provides circumstantial evidence for a silicate associated osteoporosis.
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Affiliation(s)
- A M Arens
- School of VeterinaryMedicine, University of California, Davis, CA, USA
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14
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Mohebbi I, Rad IA, Bagheri M. Association of angiotensin-1-converting enzyme gene variations with silicosis predisposition. Inhal Toxicol 2010; 22:1110-5. [DOI: 10.3109/08958378.2010.526654] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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15
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Cooper G, Gilbert K, Greidinger E, James J, Pfau J, Reinlib L, Richardson B, Rose N. Recent advances and opportunities in research on lupus: environmental influences and mechanisms of disease. CIENCIA & SAUDE COLETIVA 2010; 14:1865-76. [PMID: 19851599 DOI: 10.1590/s1413-81232009000500028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 03/05/2008] [Indexed: 12/14/2022] Open
Abstract
We summarize research on mechanisms through which environmental agents may affect the pathogenesis of lupus, discuss three exposures that have been the focus of research in this area, and propose recommendations for new research initiatives. We examined studies pertaining to key mechanistic events and specific exposures. Apoptosis leading to increased production or decreased clearance of immunogenic intracellular self-antigens and defective apoptosis of autoreactive immune cells both have been implicated in the loss of self-tolerance. The adjuvant or bystander effect is also needed to produce a sustained autoimmune response. Activation of toll-like receptors is one mechanism through which these effects may occur. Abnormal DNA methylation may contribute to the pathogenesis of lupus. Each of the specific exposures has been shown, in humans or in mice, to act upon one or more of these pathogenic steps. Specific recommendations for the continued advancement of our understanding of environmental influences on lupus and other autoimmune diseases include the development and use of mouse models with varying degrees of penetrance and manifestations of disease, identification of molecular or physiologic targets of specific exposures, development and use of improved exposure assessment methodologies, and multisite collaborations designed to examine understudied environmental exposures in humans.
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Affiliation(s)
- Glinda Cooper
- National Center for Environmental Assessment, U.S. EnvironmentalProtection Agency, Washington, DC 20460 USA.
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16
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Dobreva ZG, Prakova GR, Slavov ES, Stanilova SA. Changes of cytokine production and cell viability of peripheral blood mononuclear cells from silicosis patients: effect of in vitro treatment with acetylsalicylic acid. Toxicol Ind Health 2009; 26:3-9. [DOI: 10.1177/0748233709354555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this study, IL-6 and IL-12p40 production and cell viability of peripheral blood mononuclear cells from silicosis patients after in vitro stimulation were investigated. Furthermore, the effects of introducing acetylsalicylic acid to stimulated patients’ peripheral blood mononuclear cells on cytokine production and cell viability were determined. Nine patients with moderate silicosis, 11 with severe silicosis and 14 healthy subjects were recruited for this study. The level of IL-6 produced by patients peripheral blood mononuclear cells decreased depending on the stage of the disease. The addition of acetylsalicylic acid had significantly suppressive effect on the IL-6 production by lipopolysaccharide—stimulated patients’ peripheral blood mononuclear cells. Acetylsalicylic acid treatment of C3 binding glycoprotein—stimulated patients’ peripheral blood mononuclear cells led to significant upregulation of IL-12p40 production. Results showed a stage-dependent decrease of cell viability of peripheral blood mononuclear cells from silicosis patients. Acetylsalicylic acid significantly decreased cell viability entirely in stimulated peripheral blood mononuclear cells from patients with severe silicosis. In conclusion, this study showed that the disease progression affects peripheral blood mononuclear cells in patients with silicosis and causes functional changes that became apparent after stimulation. Our study demonstrated that in severe silicosis the treatment with acetylsalicylic acid, as an anti-inflammatory agent, might not be beneficial for patients.
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Affiliation(s)
- Zlatka Georgieva Dobreva
- Department of Molecular Biology, Immunology & Genetics, Faculty of Medicine, Trakia University, Stara Zagora, Bulgaria,
| | | | - Emil Slavov Slavov
- Department of Molecular Biology, Immunology & Genetics, Faculty of Medicine, Trakia University, Stara Zagora, Bulgaria
| | - Spaska Angelova Stanilova
- Department of Molecular Biology, Immunology & Genetics, Faculty of Medicine, Trakia University, Stara Zagora, Bulgaria
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Abstract
This review summarizes the growing body of epidemiologic and experimental research pertaining to the relationship between SLE and occupational exposures, such as crystalline silica, solvents, and pesticides. Epidemiologic studies, using different designs in different settings, have demonstrated moderate to strong associations between occupational silica exposure and SLE. Recent experimental studies of silica in lupus-prone mice provide support for the idea that, in addition to its known adjuvant effect, silica exposure increases the generation of apoptotic material, an important source of self-antigen. Despite compelling experimental studies of the organic solvent trichloroethylene (TCE) in lupus-prone mice, there is little evidence of an overall association of SLE and occupational exposure to a broad classification of solvents in humans. However, there is a lack of data on SLE in occupational cohorts with exposures to TCE or other specific solvents. One epidemiologic study reported an association of pesticide mixing and SLE, while a recent experimental study reported accelerated disease in pesticide-treated lupus-prone mice. Other occupational exposures worth investigating include asbestos, metals, and UV radiation. Attention should also be given to the role of gene-environment interactions, which may require large, multi-site studies that collect both genetic material and occupational exposure data. The quality of exposure assessment is an important consideration in designing and evaluating these studies. The use of pre-clinical endpoints (e.g. high-titer autoantibodies) in occupational cohorts with well-characterized exposure histories may reveal occupational risk factors for autoimmunity, and may also provide baseline data for studies of determinants of progression to SLE.
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Affiliation(s)
- Christine G Parks
- Biostatistics and Epidemiology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
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18
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Pasula R, Britigan BE, Turner J, Martin WJ. Airway delivery of silica increases susceptibility to mycobacterial infection in mice: potential role of repopulating macrophages. THE JOURNAL OF IMMUNOLOGY 2009; 182:7102-9. [PMID: 19454707 DOI: 10.4049/jimmunol.0803642] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Silica exposure results in an increased lifelong risk of developing mycobacterial pulmonary infections. To date, there are no animal models that replicate this finding to permit assessment of the mechanisms underlying susceptibility to mycobacterial infection. To test the hypothesis that prior silica exposure increases risk of mycobacterial infection, we intratracheally (I.T.) administered silica, a control dust (Al(2)O(3)) or saline into mechanically ventilated C57BL/6 mice. Later, the mice received Mycobacterium avium or Mycobacterium tuberculosis I.T. Mice were sacrificed at defined time points and mycobacteria in lung homogenates were quantified. M. avium or M. tuberculosis infection was markedly increased in silica-exposed mice compared with mice exposed to either Al(2)O(3) or saline beginning 3 wk after silica exposure. Similarly, lung sections from silica-exposed mice had many more acid fast bacilli(+) (AFB(+)) organisms than from control mice. Alveolar macrophages (AMs) from bronchoalveolar lavage of silica-exposed mice also revealed a higher number of mycobacteria compared with mice treated with Al(2)O(3) or saline. In addition, passive transfer of AMs from silica-exposed mice to control mice increased M. tuberculosis susceptibility. These results indicate that silica exposure converts mycobacteria-resistant mice into mycobacteria-susceptible mice via a process that likely involves a new population of AMs that are more susceptible to mycobacterial infection.
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Affiliation(s)
- Rajamouli Pasula
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA.
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19
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Serum neopterin in workers exposed to inorganic dust containing free crystalline silicon dioxide. Open Med (Wars) 2009. [DOI: 10.2478/s11536-008-0084-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe study was conducted among 92 male workers, divided into two groups depending on workplace and level of inorganic dust containing free crystalline SiO2 in the work environment, and 43 healthy workers without exposure to dust aerosols. The measured inhalable and respirable dust concentrations, as well as the concentration of free crystalline silica (FCS) in the respirable fraction were different for the two groups, but the percentage of free crystalline silica in the respirable fraction was almost identical. Significantly higher neopterin levels were found in workers exposed to dust, compared to the control group: 12.72 nmol/L and 6.32 nmol/L respectively (p<0.05). No significant difference was found between serum neopterin levels in both groups of the exposed workers. Among the groups with different length of service, a statistically higher neopterin level was evident only in the workers with length of service less than 10 years (p<0.05). The correlation analysis did not find a significant dependence of neopterin levels on the age of the studied workers or on the duration of smoking in packet years. The difference between neopterin levels in smokers and non-smokers was nonsignificant. The results obtained show that increased neopterin levels in the exposed workers are not influenced by individual features, duration and level of exposure to inorganic dust, but mostly by the presence of FCS in the respirable fraction.
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20
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Brown JM, Pfau JC, Pershouse MA, Holian A. Silica, Apoptosis, and Autoimmunity. J Immunotoxicol 2008; 1:177-87. [DOI: 10.1080/15476910490911922] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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21
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Cooper GS, Gilbert KM, Greidinger EL, James JA, Pfau JC, Reinlib L, Richardson BC, Rose NR. Recent advances and opportunities in research on lupus: environmental influences and mechanisms of disease. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:695-702. [PMID: 18560522 PMCID: PMC2430222 DOI: 10.1289/ehp.11092] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 03/05/2008] [Indexed: 05/26/2023]
Abstract
OBJECTIVES In this review we summarize research on mechanisms through which environmental agents may affect the pathogenesis of lupus, discuss three exposures that have been the focus of research in this area, and propose recommendations for new research initiatives. DATA SOURCES AND SYNTHESIS We examined studies pertaining to key mechanistic events and specific exposures. Apoptosis leading to increased production or decreased clearance of immunogenic intracellular self-antigens and defective apoptosis of autoreactive immune cells both have been implicated in the loss of self-tolerance. The adjuvant or bystander effect is also needed to produce a sustained autoimmune response. Activation of toll-like receptors is one mechanism through which these effects may occur. Abnormal DNA methylation may also contribute to the pathogenesis of lupus. Each of the specific exposures we examined--Epstein-Barr virus, silica, and trichloroethylene--has been shown, in humans or in mice, to act upon one or more of these pathogenic steps. Specific recommendations for the continued advancement of our understanding of environmental influences on lupus and other autoimmune diseases include the development and use of mouse models with varying degrees of penetrance and manifestations of disease, identification of molecular or physiologic targets of specific exposures, development and use of improved exposure assessment methodologies, and multisite collaborations designed to examine understudied environmental exposures in humans. CONCLUSIONS The advances made in the past decade concerning our understanding of mechanisms involved in the development of lupus and the influence of environmental agents on this process provide a strong foundation for further developments in this field.
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Affiliation(s)
- Glinda S Cooper
- National Center for Environmental Assessment, US Environmental Protection Agency, Washington, DC 20460, USA.
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22
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Stanilova S, Miteva L, Prakova G. IL-12Bpro and GSTP1 polymorphisms in association with silicosis. ACTA ACUST UNITED AC 2007; 71:169-74. [DOI: 10.1111/j.1399-0039.2007.00985.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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Migliaccio CT, Buford MC, Jessop F, Holian A. The IL-4Ralpha pathway in macrophages and its potential role in silica-induced pulmonary fibrosis. J Leukoc Biol 2007; 83:630-9. [PMID: 18056481 DOI: 10.1189/jlb.0807533] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Crystalline silica exposure can result in pulmonary fibrosis, where the pulmonary macrophage is key as a result of its ability to react to silica particles. In the mouse silicosis model, there is initial Th1-type inflammation, characterized by TNF-alpha and IFN-gamma. Previous studies determined that Th2 mediators (i.e., IL-13) are vital to development of pulmonary fibrosis. The present study, using in vivo and in vitro techniques, compares silica exposures between Balb/c and Th2-deficient mice in an effort to determine the link between Th2 immunity and silicosis. In long-term experiments, a significant increase in fibrosis and activated interstitial macrophages was observed in Balb/c but not IL-4Ralpha(-/-) mice. Additionally, a significant increase in Ym1 mRNA levels, a promoter of Th2 immunity, was determined in the interstitial leukocyte population of silica-exposed Balb/c mice. To elucidate the effects of silica on macrophage function, bone marrow-derived macrophages (BMdM) were exposed to particles and assayed for T cell (TC) stimulation activity. As a control, Ym1 mRNA expression in Balb/c BMdM was determined using IL-4 stimulation. In the in vitro assay, a significant increase in TC activation, as defined by surface markers and cytokines, was observed in the cultures containing the silica-exposed macrophages in wild-type and IL-4Ralpha(-/-) mice, with one exception: IL-4Ralpha(-/-) BMdM were unable to induce an increase in IL-13. These results suggest that crystalline silica alters cellular functions of macrophages, including activation of TC, and that the increase in Th2 immunity associated with silicosis is via the IL-4Ralpha-Ym1 pathway.
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Hu S, Zhao H, Yin XJ, Ma JKH. Role of mitochondria in silica-induced apoptosis of alveolar macrophages: inhibition of apoptosis by rhodamine 6G and N-acetyl-L-cysteine. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2007; 70:1403-15. [PMID: 17687726 DOI: 10.1080/15287390701251990] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Induction of apoptosis by silica in alveolar macrophages (AM) may be a critical step in silica-induced lung injury and pulmonary fibrosis. This study investigated the mechanism(s) through which silica induces apoptosis in AM and their production of proinflammatory cytokines. Using N-acetyl-L-cysteine (NAC) for glutathione (GSH) synthesis and removal of reactive oxygen species (ROS), and rhodamine 6G (R6G) to inhibit the mitochondrial-dependent function, this study found that silica-induced apoptosis of rat AM in primary culture is mitochondria dependent and exhibits a mechanism involving ROS generation, increased mitochondrial release of cytochrome c, and the activation of caspase 9, but not caspase 8, activity. Silica-induced apoptosis was accompanied by a lowering of intracellular and mitochondrial GSH (mGSH) and was blocked by pretreatment of cells with NAC or R6G. When cells were exposed to silica and then treated with either NAC or R6G, silica-induced apoptosis was not affected by the blocking agent. In addition, R6G, which inhibited cellular ATP production and mitochondrial ROS generation, had no effect on apoptosis induced by exogenous hydrogen peroxide or superoxide. Pretreatment of cells with NAC or R6G also inhibited silica-induced production of interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha, but the inhibition of these cytokines with agents known to block their secretion did not protect cells from silica-induced apoptosis. Data indicate that silica-induced apoptosis is mediated through mitochondrial generation of ROS, which may be inhibited by pretreatment of cells with R6G that prevents ROS generation, or with NAC that maintains a high level of mGSH. The secretion of IL-1beta and TNF-alpha by silica-exposed AM was markedly inhibited by NAC and R6G, suggesting that the production of these cytokines is also ROS dependent.
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Affiliation(s)
- Shuiying Hu
- School of Pharmacy, West Virginia University, Morgantown, West Virginia 26506, USA
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25
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Stanilova S, Miteva L, Prakova G. Interleukin-12B-3'UTR polymorphism in association with IL-12p40 and IL-12p70 serum levels and silicosis severity. Int J Immunogenet 2007; 34:193-9. [PMID: 17504509 DOI: 10.1111/j.1744-313x.2007.00680.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Susceptibility to silicosis and to disease severity is in part genetically determined. In this study, the role of IL-12B-3'UTR polymorphism in susceptibility and severity of silicosis and its influence on IL-12p40 and IL-12p70 serum level were investigated. The quantity of IL-12p40 and IL-12p70 was detected by enzyme-linked immunosorbent assay and the genotype of IL-12B was determined using the polymerase chain reaction-restriction fragment-length polymorphism method. We observed elevated IL-12p40 in contrast to IL-12p70 serum levels in a group of 62 silicosis patients compared with both control groups. In severe silicosis patients, we detected the highest IL-12p40 serum levels (129.1 +/- 67.7 pg mL(-1)); lower in patients with the moderate (94 +/- 41.6 pg mL(-1)), whereas in mild silicosis, the IL-12p40 levels (67 +/- 23.5 pg mL(-1)) was similar to these in healthy donors. According to IL-12B polymorphism, increased serum levels were observed in subjects with AA genotype (103.2 +/- 46.9 pg mL(-1)) compared to silicosis patients with AC genotype (82.7 +/- 38.3 pg mL(-1)). No significant differences of genotype and allele frequencies of the 3'UTR polymorphism were observed between silicosis patients and healthy controls. However, the heterozygous genotype was found approximately five times more frequently in patients with mild and moderate (48% and 52%) silicosis compared to patients with severe silicosis (11%), and that IL-12B polymorphism may contribute to silicosis severity rather than to susceptibility. Our data demonstrated that elevated serum IL-12p40, independently of IL-12p70 levels, is associated with severity of silicosis, and suggested that IL-12p40 profibrotic activity may contribute to silicosis severity.
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Affiliation(s)
- S Stanilova
- Department of Molecular Biology, Immunology and Medical Genetics, Faculty of Medicine, Trakia University, Stara Zagora, Bulgaria.
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26
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Parks CG, Cooper GS. Occupational exposures and risk of systemic lupus erythematosus: a review of the evidence and exposure assessment methods in population- and clinic-based studies. Lupus 2007; 15:728-36. [PMID: 17153843 DOI: 10.1177/0961203306069346] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Epidemiologic and experimental research suggests a potential role of occupational exposures in the development of systemic lupus erythematosus (SLE). A plausible association has been identified in studies of occupational silica exposure and SLE, complemented by experimental studies in lupus-prone mice exploring potential mechanisms related to apoptosis and immune dysregulation. Experimental studies of the solvent trichloroethylene in lupus-prone mice provide evidence of effects on immune function, including increased production of autoantibodies and activation of CD4+ T cells. However, few studies of occupational solvent exposure and SLE have been conducted, and those that are available show little evidence of an association. There is some suggestion from the available studies of the potential influence of pesticides on SLE, but as with solvents, the specific type of pesticides that may be implicated is not known. Our understanding of the role of occupational exposures in SLE could be advanced by the development of larger, multisite or parallel studies that utilize similar questionnaire and exposure evaluation methods. Multiple studies using comparable exposure measures are needed to provide sufficient sample size for examining gene-environment interactions. We provide a general overview of data requirements and methods available for the assessment and evaluation of occupational exposures in clinical and population-based studies of SLE.
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Affiliation(s)
- C G Parks
- Biostatistics and Epidemiology Branch, Health Effects Laboratory Division, National Institute of Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505, USA.
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27
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Carlsten C, de Roos AJ, Kaufman JD, Checkoway H, Wener M, Seixas N. Cell markers, cytokines, and immune parameters in cement mason apprentices. ACTA ACUST UNITED AC 2007; 57:147-53. [PMID: 17266079 DOI: 10.1002/art.22483] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Cement masons are known to have significant silica exposure, and silica exposure and silicosis are thought to increase risk of autoimmune disease. Because the mechanisms remain obscure, with inconclusive reports of systemic immune effects following silica exposure, our goal was to identify potential early markers of silica-related immunologic and respiratory effects. METHODS We conducted a cross-sectional study of cement mason apprentices and electrician (control) apprentices. Demographics, dust exposure history, symptoms, spirometry, exhaled nitric oxide, and blood (for immunoglobulins, cytokines, cell counts, and surface markers) were obtained from 11 cement mason apprentices and a comparison group of 21 electrician apprentices. RESULTS Masons had significantly higher (P < 0.05) masonry dust exposure (42 versus 9 dust-hour-years), serum interleukin-1beta (IL-1beta; 12 versus 9 pg/ml), IL-2 (20 versus 8 pg/ml), IL-4 (193 versus 67 pg/ml), IL-10 (44 versus 21 pg/ml), and interferon-gamma (139 versus 65 pg/ml) compared with electricians. In contrast, masons had significantly lower percentages of CD25+ (12% versus 20%) and CD69+ (4% versus 9%) lymphocytes. CONCLUSION Mason apprentices had higher levels of serum proinflammatory cytokines and lower percentages of CD25+ and CD69+ lymphocytes than did electrician apprentices. These preliminary findings suggest that mason apprentices may be at greater risk of a systemic proinflammatory state that is potentially linked to immune dysregulation. Although distinct limitations of this preliminary data are recognized, this is consistent with early biologic effects leading to increased incidence of autoimmune disease among silica-exposed workers. Prospective studies are needed to validate these initial findings and clarify the temporal sequence of observed relationships.
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Affiliation(s)
- C Carlsten
- University of Washington, Department of Medicine, 4225 Roosevelt Way NE, Suite 100, Seattle, WA 98105, USA.
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Misson P, Brombacher F, Delos M, Lison D, Huaux F. Type 2 immune response associated with silicosis is not instrumental in the development of the disease. Am J Physiol Lung Cell Mol Physiol 2007; 292:L107-13. [PMID: 16997884 DOI: 10.1152/ajplung.00503.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It has been proposed that the development of lung fibrosis is associated with a T helper type 2 response, mainly characterized by IL-4 and IL-13 production. We investigated the potential role of type 2 immune polarization in the silicotic process and examined the pulmonary response to silica particles in mice genetically deficient for IL-4. We found that IL-4−/− mice were not protected against the development of silicosis, suggesting that IL-4 is not essential for the development of this fibrotic disease. By evaluating the intensity of silica-induced lung fibrosis in mice deficient for IL-4 receptor α (IL-4Rα), we showed that the establishment of pulmonary fibrosis was independent of both IL-4 and IL-13. Strong impairment of the type 2 immune response (IgG1) in the lungs of IL-4−/− and IL-4Rα−/− mice did not affect the development of the disease. Measurement of IL-13α2 receptor expression and IgG2a, IL-12p70, and IFN-γ levels in silica-treated IL-4−/− and IL-4Rα−/− animals showed that the development of silicosis was not related to an IL-13 signaling pathway or a switch to a type 1 response in deficient animals. Our data clearly indicate that the type 2 immune response associated with silicosis in mice is not required for the development of this inflammatory and fibrotic disease.
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Affiliation(s)
- Pierre Misson
- Unit of Industrial Toxicology and Occupational Medicine, Université Catholique de Louvain, 53.02 Ave. E. Mounier, 1200 Brussels, Belgium
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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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30
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Hu S, Zhao H, Al-Humadi NH, Yin XJ, Ma JKH. Silica-induced apoptosis in alveolar macrophages: evidence of in vivo thiol depletion and the activation of mitochondrial pathway. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2006; 69:1261-84. [PMID: 16754540 DOI: 10.1080/15287390500361875] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Studies have shown that silica induces apoptosis through mechanisms that also regulate the inflammatory responses of lung cells to silica exposure. Although implicated in cell culture studies, the major in vivo pathway through which silica induces apoptosis has not been characterized. The present study is to study the role of mitochondria in silica-induced oxidative stress and apoptosis in vivo. Rats were intratracheally instilled with saline or silica (20 mg/kg) and sacrificed at 3 days post-exposure unless otherwise specified. Alveolar macrophages (AM) were harvested by bronchoalveolar lavage and measured for apoptosis and secretion of inflammatory mediators in the presence or absence of appropriate inhibitors. Concurrent studies were carried out to determine the presence of intracellular reactive oxygen species (ROS) via confocal microscopy, mitochondrial trans-membrane potential by flow cytometry, mitochondrial release of cytochrome c, and the activation of caspase activities in AM by Western blot analysis. Silica was shown to induce elevated levels of intracellular ROS, resulting in a marked decrease in intracellular glutathione (GSH) and cysteine and a sustained presence of apoptotic AM in silica-exposed rats up to two weeks post-exposure. The apoptotic AM were characterized by decreased mitochondrial trans-membrane potential, increased mitochondrial release of cytochrome c, activated caspase 9 (but not caspase 8) and caspase 3 activities, and PARP degradation, comparing to cells from the saline control. Silica induced AM production of IL-1 and TNF-alpha, which may be inhibited by ex vivo treatment of cells with N-acetylcysteine (NAC) or microtubule modifiers such as tetrandrine and taxol. NAC was shown to prevent intracellular GSH depletion and silica-induced production of IL-1beta and TNF-alpha but not apoptosis in AM from silica-exposed rats. These results show that silica-induced apoptosis is mediated through the mitochondrial pathway but not through cellular production of inflammatory cytokines, ROS generation, however, induces both apoptosis and cellular secretion of inflammatory mediators.
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Affiliation(s)
- Shuiying Hu
- School of Pharmacy, West Virginia University, Morgantown, WV 26506, USA
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31
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Yun AJ, Lee PY, Gerber AN. Integrating systems biology and medical imaging: understanding disease distribution in the lung model. AJR Am J Roentgenol 2006; 186:925-30. [PMID: 16554557 DOI: 10.2214/ajr.05.0072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Many chronic diseases exhibit characteristic pulmonary distribution patterns, but the underlying biologic explanations remain elusive. On the basis of emerging evidence from systems biology, we propose that gradients of T helper immune function exist as an epiphenomenon of the hypoxic pulmonary vasoconstriction response. Regional variation of immune function may contribute to preferential distribution patterning of lung diseases. CONCLUSION The lungs represent but one example in which the distribution of immune function throughout the body may explain disease location. This hypothetic framework can apply to diseases outside the realm of pulmonary biology and illustrates the potential benefit of integrating advances in systems biology and medical imaging.
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Affiliation(s)
- Anthony J Yun
- Department of Radiology, Stanford University, 470 University Ave., Palo Alto, CA 94301, USA.
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Garn H, Siese A, Stumpf S, Wensing A, Renz H, Gemsa D. Phenotypical and functional characterization of alveolar macrophage subpopulations in the lungs of NO2-exposed rats. Respir Res 2006; 7:4. [PMID: 16398938 PMCID: PMC1368986 DOI: 10.1186/1465-9921-7-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Accepted: 01/06/2006] [Indexed: 11/25/2022] Open
Abstract
Background Alveolar macrophages (AM) are known to play an important role in the regulation of inflammatory reactions in the lung, e.g. during the development of chronic lung diseases. Exposure of rats to NO2 has recently been shown to induce a shift in the activation type of AM that is characterized by reduced TNF-α and increased IL-10 production. So far it is unclear, whether a functional shift in the already present AM population or the occurrence of a new, phenotypically different AM population is responsible for these observations. Methods AM from rat and mice were analyzed by flow cytometry for surface marker expression and in vivo staining with PKH26 was applied to characterize newly recruited macrophages. Following magnetic bead separation, AM subpopulations were further analyzed for cytokine, inducible NO synthase (iNOS) and matrix metalloproteinase (MMP) mRNA expression using quantitative RT-PCR. Following in vitro stimulation, cytokines were quantitated in the culture supernatants by ELISA. Results In untreated rats the majority of AM showed a low expression of the surface antigen ED7 (CD11b) and a high ED9 (CD172) expression (ED7-/ED9high). In contrast, NO2 exposure induced the occurrence of a subpopulation characterized by the marker combination ED7+/ED9low. Comparable changes were observed in mice and by in vivo labeling of resident AM using the dye PKH26 we could demonstrate that CD11b positive cells mainly comprise newly recruited AM. Subsequent functional analyses of separated AM subpopulations of the rat revealed that ED7+ cells showed an increased expression and production of the antiinflammatory cytokine IL-10 whereas TNF-α production was lower compared to ED7- AM. However, iNOS and IL-12 expression were also increased in the ED7+ subpopulation. In addition, these cells showed a significantly higher mRNA expression for the matrix metalloproteinases MMP-7, -8, -9, and -12. Conclusion NO2 exposure induces the infiltration of an AM subpopulation that, on the one hand may exert antiinflammatory functions by the production of high amounts of IL-10 but on the other hand may contribute to the pathology of NO2-induced lung damage by selective expression of certain matrix metalloproteinases.
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Affiliation(s)
- Holger Garn
- Department of Clinical Chemistry and Molecular Diagnostics, Philipps University of Marburg, Biomedical Research Center, Hans-Meerwein-Str., 35043 Marburg, Germany
| | - Anette Siese
- Institute of Immunology, Philipps University of Marburg, Robert-Koch-Str. 17, 35037 Marburg, Germany
| | - Sabine Stumpf
- Institute of Immunology, Philipps University of Marburg, Robert-Koch-Str. 17, 35037 Marburg, Germany
| | - Anka Wensing
- Department of Clinical Chemistry and Molecular Diagnostics, Philipps University of Marburg, Biomedical Research Center, Hans-Meerwein-Str., 35043 Marburg, Germany
| | - Harald Renz
- Department of Clinical Chemistry and Molecular Diagnostics, Philipps University of Marburg, Biomedical Research Center, Hans-Meerwein-Str., 35043 Marburg, Germany
| | - Diethard Gemsa
- Institute of Immunology, Philipps University of Marburg, Robert-Koch-Str. 17, 35037 Marburg, Germany
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Davis GS, Pfeiffer LM, Hemenway DR, Rincon M. Interleukin-12 is not essential for silicosis in mice. Part Fibre Toxicol 2006; 3:2. [PMID: 16396683 PMCID: PMC1360681 DOI: 10.1186/1743-8977-3-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2005] [Accepted: 01/05/2006] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Silicosis features foci of inflammation where macrophages and lymphocytes precede and accompany fibroblast proliferation, alveolar epithelial hyperplasia, and increased deposition of connective tissue matrix material. In the mouse following silica inhalation there is recruitment of natural killer-, B-, and CD4+ and CD8+ lymphocytes to the alveolar spaces, enlargement of bronchial-associated lymphoid tissues (BALT), and aggregation of lymphocytes surrounding small airways and blood vessels. A substantial fraction of the recruited lung lymphocytes produce interferon-gamma (IFN-gamma), and IFN-gamma gene-deleted mice develop less silicosis than wild-type mice. Interleukin-12 (IL-12) is an important pathway for driving the adaptive immune response towards a TH1-like phenotype. We hypothesized that IL-12 might stimulate lymphocyte activation and the up-regulation of IFN-gamma, and consequently be an essential mediator for silicosis. RESULTS C57Bl/6 wild-type (WT) and IL-12 deficient (IL-12 KO) mice were exposed to sham-air or crystobalite silica (61 mg/m3) by inhalation for 5 hours/day for 12 days and then studied from 1 to 112 days after exposure. Mice exposed to sham-air had normal lung histology at all time points. WT mice exposed to titanium dioxide (72 mg/m3) showed pulmonary macrophage recruitment but no increase in lung collagen. Both WT and IL-12 KO mice exposed to silica showed similar progressive lung pathology, increased wet lung weight and increased total lung collagen (hydroxyproline). IL-12 p35 mRNA was not increased in either strain after silica exposure; IL-12 p40 mRNA was up-regulated after silica in WT mice and constitutively absent in the IL-12 KO mice. IL-18 mRNA was not increased after silica exposure. The expression of IL-15 (an important driver for innate immunity, Natural Killer cell activation, and IFN-gamma production) was abundant in air-exposed mice and was increased slightly in the lungs of mice with silicosis. CONCLUSION The axis of IL-12 driving IFN-gamma production is not essential for the full manifestations of silicosis in mice exposed to a crystobalite silica aerosol.
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Affiliation(s)
- Gerald S Davis
- Pulmonary Disease & Critical Care Medicine Unit, Department of Medicine, College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Linda M Pfeiffer
- Pulmonary Disease & Critical Care Medicine Unit, Department of Medicine, College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - David R Hemenway
- Department of Civil & Environmental Engineering, College of Engineering & Mathematical Sciences, University of Vermont, Burlington, Vermont, USA
| | - Mercedes Rincon
- Immunobiology Unit, Department of Medicine, College of Medicine, University of Vermont, Burlington, Vermont, USA
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Hubbs A, Greskevitch M, Kuempel E, Suarez F, Toraason M. Abrasive blasting agents: designing studies to evaluate relative risk. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2005; 68:999-1016. [PMID: 16020188 DOI: 10.1080/15287390590912612] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Workers exposed to respirable crystalline silica used in abrasive blasting are at increased risk of developing a debilitating and often fatal fibrotic lung disease called silicosis. The National Institute for Occupational Safety and Health (NIOSH) recommends that silica sand be prohibited as abrasive blasting material and that less hazardous materials be used in blasting operations. However, data are needed on the relative risks associated with exposure to abrasive blasting materials other than silica. NIOSH has completed acute studies in rats (Hubbs et al., 2001; Porter et al., 2002). To provide dose-response data applicable to making recommendation for occupational exposure limits, NIOSH has collaborated with the National Toxicology Program (NTP) to design longer term studies with silica substitutes. For risk assessment purposes, selected doses will include concentrations that are relevant to human exposures. Rat lung burdens achieved should be comparable to those estimated in humans with working lifetime exposures, even if this results in "overloading" doses in rats. To quantify both dose and response, retained particle burdens in the lungs and lung-associated lymph nodes will be measured, as well as biochemical and pathological indices of pulmonary response. This design will facilitate assessment of the pulmonary fibrogenic potential of inhaled abrasive blasting agents at occupationally relevant concentrations.
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Affiliation(s)
- Ann Hubbs
- National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA.
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35
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Cooper GS, Parks CG. Occupational and environmental exposures as risk factors for systemic lupus erythematosus. Curr Rheumatol Rep 2005; 6:367-74. [PMID: 15355749 DOI: 10.1007/s11926-004-0011-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although genetic susceptibility plays a strong role in the etiology of systemic lupus erythematosus (SLE), recent research has provided new evidence of the potential influence of environmental factors in the risk for this disease. This paper describes epidemiologic and experimental research pertaining to occupational and environmental sources of exposure to respirable crystalline silica, solvents and pesticides, and two "lifestyle" factors (smoking and hair dye use). As has been seen with other systemic autoimmune diseases (eg, systemic sclerosis and rheumatoid arthritis), a series of epidemiologic studies, using different designs in different settings, have demonstrated relatively strong and consistent associations between occupational silica exposure and SLE. The type and quality of exposure assessment is an important consideration in evaluating these studies. Recent experimental studies examined the effect of trichloroethylene exposure in MRL+/+ mice, but to date there have been few epidemiologic studies of solvents and SLE. There are numerous avenues with respect to environmental factors in SLE that need additional research.
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Affiliation(s)
- Glinda S Cooper
- Epidemiology Branch MDA3-05, National Institute of Environmental Health Sciences, PO Box 12233, Durham, NC 27709, USA.
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Garn H, Siese A, Stumpf S, Barth PJ, Müller B, Gemsa D. Shift toward an alternatively activated macrophage response in lungs of NO2-exposed rats. Am J Respir Cell Mol Biol 2003; 28:386-96. [PMID: 12594066 DOI: 10.1165/rcmb.4888] [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: 11/24/2022] Open
Abstract
Inflammatory mechanisms are thought to play an important role in the pathogenesis of acute and chronic obstructive pulmonary diseases. In a rat inhalation model using continuous exposure to 10 ppm nitrogen dioxide for 1, 3, and 20 d, we investigated the inflammatory response with particular focus on the activation state of alveolar macrophages. Whereas the number of inflammatory cells and total protein concentration were increased in the bronchoalveolar lavage (BAL), the amount of the proinflammatory cytokine tumor necrosis factor-alpha was markedly reduced with increasing exposure time. In contrast, interleukin (IL)-10 and IL-6 were found at elevated levels and intracellular amounts of suppressor of cytokine signaling-3 protein increased in BAL cells. Upon in vitro lipopolysaccharide stimulation, BAL cells revealed reduced capability to produce the proinflammatory mediators tumor necrosis factor-alpha, IL-1 beta, and nitric oxide, but showed markedly increased transcription and protein release for IL-10. In addition, elevated levels of IL-6, scavenger receptor B, and suppressor of cytokine signaling-3 mRNA were detected in BAL cells from exposed animals. Analyses of highly purified alveolar macrophages indicated that changes in the activation state of these cells were responsible for the observed effects. In conclusion, a priming toward development of the alternatively activated macrophage phenotype occurred in the lungs of rats following nitrogen dioxide inhalation.
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Affiliation(s)
- Holger Garn
- Institute of Immunology, Department of Pathology, Laboratory of Lung Cell Biology, Philipps University Marburg, Marburg, Germany.
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Borges VM, Lopes MF, Falcão H, Leite-Júnior JH, Rocco PRM, Davidson WF, Linden R, Zin WA, DosReis GA. Apoptosis underlies immunopathogenic mechanisms in acute silicosis. Am J Respir Cell Mol Biol 2002; 27:78-84. [PMID: 12091249 DOI: 10.1165/ajrcmb.27.1.4717] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We investigated immunopathogenic roles for apoptosis in acute murine silicosis. Intratracheal silica instillation induced pulmonary inflammation and enlarged thoracic lymph nodes. Lymphocytes from silica-exposed lymph nodes showed reduced mitogenic responses to T cell receptor (TCR) stimulation, and markedly increased activation-induced cell death, compared with control lymphocytes from saline-exposed lymph nodes. CD4(+) T cell death was mediated by Fas ligand, because CD4(+) T cells from Fas ligand-deficient gld mice did not undergo activation-induced apoptosis. Silica deposition also resulted in increased apoptosis associated with inflammatory infiltrates in lung parenchyma. In vivo treatment with caspase inhibitors reduced neutrophil accumulation, and alleviated inflammation in the lungs of silica-treated mice. These results suggest that silica-induced apoptosis plays an inflammatory role in the lung parenchyma, and creates immunologic abnormalities in regional lymph nodes, with pathogenic implications for the host.
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Affiliation(s)
- Valeria M Borges
- Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Brazil
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Hubbard AK, Timblin CR, Shukla A, Rincón M, Mossman BT. Activation of NF-kappaB-dependent gene expression by silica in lungs of luciferase reporter mice. Am J Physiol Lung Cell Mol Physiol 2002; 282:L968-75. [PMID: 11943661 DOI: 10.1152/ajplung.00327.2001] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Occupational exposure to crystalline silica is associated with the development of pulmonary inflammation and silicosis, yet how silica initiates pulmonary fibrosis and which cell types are involved are unclear. In studies here, we hypothesized that silica particles interact initially with pulmonary epithelial cells and alveolar macrophages (AMs) to cause transcriptional activation of nuclear factor (NF)-kappaB-regulated genes encoding inflammatory cytokines. Exposure of NF-kappaB luciferase reporter mice intratracheally to silica or lipopolysaccharide (LPS), but not the nonfibrogenic particle titanium dioxide (TiO(2)), increased immunoreactivity of luciferase protein in bronchiolar epithelial cells and AMs. Ribonuclease protection assays revealed significant (P < or = 0.05) increases in mRNA levels of inducible nitric oxide synthase, tumor necrosis factor-alpha, macrophage inflammatory protein-2, macrophage chemotactic protein-1 (MCP-1), interferon-gamma, interleukin (IL)-6, and IL-12 in lung homogenates of reporter mice after exposures to silica or LPS. Immunoreactivity of MCP-1 in these animals was localized to AMs and epithelial cells. These data are the first to show activation of NF-kappaB in situ by fibrogenic particles in pulmonary epithelial cells and AMs. Increased expression of NF-kappaB-related inflammatory cytokines by these cell types, which first encounter silica after inhalation, may be critical to the initiation of silica-associated lung diseases, thus providing a rationale for focusing on NF-kappaB in preventive and therapeutic strategies.
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Affiliation(s)
- Andrea K Hubbard
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs 06269, USA
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Manetz TS, Pettit DA, Meade BJ. The determination of draining lymph node cell cytokine mRNA levels in BALB/c mice following dermal sodium lauryl sulfate, dinitrofluorobenzene, and toluene diisocyanate exposure. Toxicol Appl Pharmacol 2001; 171:174-83. [PMID: 11243917 DOI: 10.1006/taap.2000.9123] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Differential modulation has been demonstrated in interleukin-4 (IL-4), IL-10, and interferon gamma (IFN-gamma) mRNA and protein secretion patterns of cells isolated from the draining lymph nodes of mice following exposure to T cell and respiratory sensitizers. Using a multiprobe ribonuclease protection assay, the following investigation examined the mRNA expression patterns of multiple cytokines associated with respiratory sensitization for modulation following exposure to chemicals known primarily to induce irritation (sodium lauryl sulfate), respiratory sensitization (toluene diisocyanate), or T cell-mediated hypersensitivity (dinitrofluorobenzene) responses. On days 0 and +5 female BALB/c mice were exposed to either test article or vehicle on the shaven dorsal lumbar region; on days +10 through +12 the mice received test article on the dorsal aspect of each ear. On day +13 animals were euthanized, draining lymph nodes were excised, and mRNA was isolated immediately or following 24 or 48 h of culture in the presence or absence of concanavalin (Con) A. Differential expression of cytokine mRNA was most notable following 24 h incubation with Con A. Modulation of IL-4, -10, and IFN-gamma following chemical exposure was consistent with previous studies. In addition, IL-9, -13, and -15 were significantly elevated only following toluene diisocyanate exposure. Further investigations of these cytokines may provide additional insight into the mechanisms of chemically induced respiratory sensitization and provide endpoints for the detection of a chemical's ability to elicit IgE-mediated hypersensitivity responses.
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Affiliation(s)
- T S Manetz
- Department of Pharmacology and Toxicology, Medical College of Virginia/VCU, Richmond, Virginia 23284, USA
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