Gene expression profiling of A549 cells exposed to Milan PM2.5

Background: Particulate matter (PM) has been associated to adverse health effects in exposed population and DNA damage has been extensively reported in in vitro systems exposed to fine PM (PM2.5). The ability to induce alterations in gene expression profile, production of reactive oxygen species (ROS) and single strand breaks to DNA molecules has been investigated in A549 cells exposed to winter and summer Milan fine PM. Results: A549 cell were exposed to 10µg/cm2 of winter and summer PM2.5 and both the PM2.5 resulted to be cytotoxic and to induce a significant increase of ROS at three h of treatment. Despite these similar effects winter PM induced a higher number of gene modulation in comparison with summer PM. Moreover the winter fraction modulated two proto-oncogenes genes (JUN and FOS). The results obtained with the microarray approach have been confirmed by qPCR and by the analysis of CYP1B1expression. Comet assay evidenced that winter PM2.5 induced more DNA single strand breaks than the summer one. Conclusion: winter PM2.5 is able to induce gene expression alteration, ROS production and DNA damage. These effects are likely to be related to the CYP enzyme activation in response to the polycyclic aromatic hydrocarbons(PAHs) adsorbed on particle surface.