Title: Radical-containing particles activate dendritic cells and enhance Th17 inflammation in a mouse model of asthma.
Authors: Wang, Pingli; Thevenot, Paul; Saravia, Jordy; Ahlert, Terry; Cormier, Stephania A
Published In Am J Respir Cell Mol Biol, (2011 Nov)
Abstract: We identified a previously unrecognized component of airborne particulate matter (PM) formed in combustion and thermal processes, namely, environmentally persistent free radicals (EPFRs). The pulmonary health effects of EPFRs are currently unknown. In the present study, we used a model EPFR-containing pollutant-particle system referred to as MCP230. We evaluated the effects of MCP230 on the phenotype and function of bone marrow-derived dendritic cells (BMDCs) in vitro and lung dendritic cells (DCs) in vivo, and the subsequent T-cell response. We also investigated the adjuvant role of MCP230 on airway inflammation in a mouse model of asthma. MCP230 decreased intracellular reduced glutathione (GSH) and the GSH/oxidized glutathione ratio in BMDCs, and up-regulated the expression of costimulatory molecules CD80 and CD86 on DCs. The maturation of DCs was blocked by inhibiting oxidative stress or the uptake of MCP230. BMDCs exposed to MCP230 increased their antigen-specific T-cell proliferation in vitro. In a model of asthma, exposure to MCP230 exacerbated pulmonary inflammation, which was attributed to the increase of neutrophils and macrophages but not eosinophils. This result correlated with an increase in Th17 cells and cytokines, compared with non-MCP230-treated but ovalbumin (OVA)-challenged mice. The percentage of Th2 cells was comparable between OVA and OVA + MCP230 mice. Our data demonstrate that combustion-generated, EPFR-containing PM directly induced the maturation of DCs in an uptake-dependent and oxidative stress-dependent manner. Furthermore, EPFR-containing PM induced a Th17-biased phenotype in lung, accompanied by significant pulmonary neutrophilia. Exposure to EPFR-containing PM may constitute an important and unrecognized risk factor in the exacerbation and development of a severe asthma phenotype in humans.
PubMed ID: 21493781
MeSH Terms: Animals; Asthma/immunology*; B7-1 Antigen/biosynthesis; B7-1 Antigen/immunology; B7-2 Antigen/biosynthesis; B7-2 Antigen/immunology; CD4-Positive T-Lymphocytes/drug effects; CD4-Positive T-Lymphocytes/immunology; Cell Differentiation/drug effects; Cell Differentiation/immunology; Cells, Cultured; Dendritic Cells/drug effects; Dendritic Cells/immunology*; Disease Models, Animal; Female; Free Radicals/adverse effects*; Free Radicals/pharmacology; Glutathione/immunology; Glutathione/metabolism; Lung/drug effects; Lung/immunology; Macrophages, Alveolar/drug effects; Macrophages, Alveolar/immunology; Male; Mice; Mice, Inbred BALB C; Mice, Transgenic; Neutrophils/drug effects; Neutrophils/microbiology; Oxidative Stress/drug effects; Oxidative Stress/immunology; Particulate Matter/adverse effects*; Particulate Matter/chemistry; Particulate Matter/pharmacology; Th17 Cells/drug effects; Th17 Cells/immunology*; Th2 Cells/drug effects; Th2 Cells/immunology; Up-Regulation/drug effects; Up-Regulation/immunology