Season linked responses to fine and quasi-ultrafine Milan PM in cultured cells
E Longhin1, E Pezzolato, P Mantecca
1Polaris Research Center, Department of Environmental Science, University Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy. e.longhin1@campus.unimib.it
Abstract:
Exposure to urbane airborne particulate matter (PM) is related to the onset and exacerbation of cardiovascular and respiratory diseases. The fine (PM1), and quasi-ultrafine (PM0.4) Milan particles collected during different seasons have been characterised and the biological effects on human epithelial lung A549, monocytes THP-1 cells and their co-culture, evaluated and compared with the results obtained on the PM10 and PM2.5 fractions. Chemical composition and transmission electron microscopy (TEM) analysis of PM0.4 showed that this fraction was very similar to PM1 for biological responses and dimension. All the winter fractions increased within 1h the level of reactive oxygen species (ROS), while only summer PM2.5 had this effect on A549 cells. The phosphorylation of H2AX (γH2AX), a marker of double strand DNA breaks (DSBs), was increased by all the winter fractions on A549 and THP-1 cells while summer PM samples did not induced this effect. PM0.4 and PM1 biological effects are partly similar and related to the season of sampling, with effects on ROS and DNA damage induced only by winter PM fractions. The winter PM damaging effect on DNA correlates with the presence of organic compounds.
Insights
Winter airborne particulate matter (PM) fractions, especially PM0.4 and PM1, significantly increase reactive oxygen species (ROS) and DNA damage in lung cells. Seasonal differences in PM composition influence its biological effects, with organic compounds linked to winter PM
Area of Science:
- Environmental Health
- Toxicology
- Cell Biology
Background:
- Urban airborne particulate matter (PM) exposure is linked to cardiovascular and respiratory diseases.
- Different PM size fractions (PM0.4, PM1, PM2.5, PM10) may exert varying biological effects.
- Seasonal variations in PM composition can influence its toxicity.
Purpose of the Study:
- To characterize fine (PM1) and quasi-ultrafine (PM0.4) Milan particles collected in different seasons.
- To evaluate and compare the biological effects of PM0.4 and PM1 with PM2.5 and PM10.
- To investigate the cellular responses, including reactive oxygen species (ROS) generation and DNA damage, induced by PM exposure.
Main Methods:
- Collection and characterization of PM samples from Milan during different seasons.
- Transmission electron microscopy (TEM) for particle analysis.
- In vitro exposure of human lung epithelial (A549) and monocyte (THP-1) cells, and their co-culture, to PM fractions.
- Measurement of reactive oxygen species (ROS) levels.
- Assessment of DNA double-strand breaks (DSBs) using phosphorylation of H2AX (γH2AX).
Main Results:
- PM0.4 and PM1 fractions showed similar dimensions and biological responses.
- All winter PM fractions significantly increased ROS levels within 1 hour in A549 cells.
- Only summer PM2.5 induced ROS in A549 cells.
- Winter PM fractions induced γH2AX in both A549 and THP-1 cells, indicating DNA damage.
- Summer PM samples did not induce significant DNA damage.
- The DNA damaging effect of winter PM correlated with the presence of organic compounds.
Conclusions:
- PM0.4 and PM1 exhibit biological effects comparable to larger PM fractions.
- Seasonal variations are critical, with winter PM fractions posing a greater risk for ROS generation and DNA damage.
- Organic compounds in winter PM are likely responsible for its genotoxic effects.
- These findings highlight the importance of PM size and seasonal composition in assessing health risks.
