Induction of Inflammatory Responses in Human Bronchial Epithelial Cells by Pb 2+ -Containing Model PM 2.5 Particles via Downregulation of a Novel Long Noncoding RNA lnc-PCK1-2:1.

Airborne particular matter (PM2.5) contains complex mixtures of pollutants, and their compositions also vary with time and location. Inhalation of PM2.5 may cause a number of diseases, such as bronchial and lung inflammation and lung cancer. So far, how different components of PM2.5 contribute to inflammation and toxicity is still not known. To identify key PM2.5 components that are responsible for inflammation, here we took a reductionism approach and synthesized a model PM2.5 library containing 20 carbon nanoparticle based members with loadings of As(III), Pb2+, Cr(VI), and BaP individually or in combination at environment relevant concentrations. We discovered that only carbon nanoparticle Pb2+ adducts, not other pollutants or adducts, induced inflammation in human bronchial cells by suppressing the expression of a novel long noncoding RNA lnc-PCK1-2:1, while Inc-PCK1-2:1 routinely plays a regulatory role in inhibiting inflammation. This finding was further substantiated by varying Pb2+ loadings on carbon nanoparticles and overexpressing Inc-PCK1-2:1. The success of this approach opens an avenue for further elucidation of molecular mechanisms of PM2.5-induced inflammation and toxicity.