The Impact of Organic Extracts of Seasonal PM2.5 on Primary Human Lung Epithelial Cells and Their Chemical Characterization

Abstract Background: Lung epithelial cells serve as first line of defense against various inhaled pollutant particles. This study focused on assessing the impact of organic extracts of PM2.5 collected in Seoul, South Korea on primary human lung epithelial cells and identifying the relevant components and sources which induced lung epithelial cell injury.Results: We used primary lung epithelial cells isolated directly from healthy donors and evaluated the effects of organic compounds of twelve selected, seasonal PM2.5 on inflammation, cellular aging, and macroautophagy in primary lung epithelial cells. Organic extracts of PM2.5 specifically induced neutrophilic chemokine, interleukin-8, via extracellular signal regulated kinase activation. Moreover, PM2.5 significantly increased the expression of aging markers (p16, p21, and p27) and activated macroautophagy. Average mass concentrations, OC and EC, had no significant correlations with PM2.5 effects. However, regression analysis showed that polycyclic aromatic hydrocarbons and n-alkanes were the most relevant components of PM2.5 correlated with neutrophilic inflammation. Vegetative detritus and residential bituminous coal combustion sources were strongly correlated with neutrophilic inflammation, aging and macroautophagy activation.Conclusions: These data suggest that the chemical composition of PM2.5 is crucially important to determine the adverse health effects of PM2.5. Our study provides encouraging evidence to regulate the harmful components of PM2.5 in Seoul.