Urban Dust Nanoparticles Induce Pro-inflammatory Activation of Neutrophils and Macrophages

Urban dust particles are a major pathogenic factor in respiratory diseases such as asthma and chronic obstructive pulmonary disease, and also increase the risk of cardiovascular diseases, and lung cancer. Nanoparticles (NPs) of various origins are an important component of urban dust, but their effects on the human body are barely studied. In the present work, the effect of urban dust NPs on innate immune cells, neutrophils and macrophages was investigated in vitro. The study used urban dust NPs isolated from urban dust samples using the coiled tube field-flow fractionation technique. Urban dust NPs were shown to induce a significant increase in the production of reactive oxygen species in human neutrophils. Preincubation of neutrophils with dust NPs resulted in a fourfold increase in production of reactive oxygen species in response to the chemoattractant peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP), which indicates an effect of neutrophil priming with nanoparticles. On macrophages differentiated from the monocytic line THP-1, urban dust NPs stimulated the secretion of pro-inflammatory cytokines, tumor necrosis factor, and interleukin-6. The inflammatory activation of neutrophils and macrophages was reduced by antibiotic polymyxin B, which is able to bind bacterial wall lipopolysaccharide. The results suggest that the pro-inflammatory effect of urban dust NPs on neutrophils and macrophages is, at least in part, due to the presence of bacterial wall lipopolysaccharide.