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Growth of airway epithelial cells at an air-liquid interface changes both the response to particle exposure and iron homeostasis.
Citation:
SOUKUP, J. M., A. J. GHIO, L. A. DAILEY, J. G. STONEHUERNER, J. H. Richards, M. Brighton, A. J. Rose, AND R. B. DEVLIN. Growth of airway epithelial cells at an air-liquid interface changes both the response to particle exposure and iron homeostasis. Presented at American Thoracic Society (ATS) Annual meeting, San Francisco, CA, May 18 - 23, 2012.
Impact/Purpose:
Growth of airway epithelial cells at an air-liquid interface changes both the response to particle exposure and iron homeostasis.
Description:
RATIONALE: We tested the hypothesis that 1) relative to submerged cells, airway epithelial cells grown at an air-liquid interface and allowed to differentiate would have an altered response to particle exposure and 2) that these differences would be associated with indices of iron homeostasis. METHODS: Human bronchial epithelial cells and BEAS-2B cells were grown both submerged and at air-liquid interface. Following exposure to particles, endpoints of oxidative stress and inflammation were quantified. In addition, indices ofiron homeostasis were measured. RESULTS: RNA for IL-8, IL-6, heme oxygenase 1 and cyclooxygenase 2 increased following exposure ofsubmerged airway epithelial cells to ambient air pollution particle. The same cells allowed to differentiate at an air-liquid interface demonstrated no such changes following particle exposure. Airway epithelial cells showed no changes in iron, ferritin, and divalent metal transporter 1 (DMT1) when grown for 21 days submerged in media. In contrast, these three indices of iron homeostasis increased in cells grown for 21 days at an air-liquid interface. To test for an association between changes in iron homeostasis with senescence and altered sensitivity to particle exposure, older rats were used in studies. Relative to 2 month old animals, those animals 18 months old demonstrated a decreased biological effect ofparticle exposure. Older animals had greater concentrations of liver and lung non-heme iron and higher serum ferritin values compared to the younger rats. Qualitative differences in DMTI were observed with increased expression ofthis transport protein in the older animals. CONCLUSIONS: We conclude that growth ofairway epithelial cells at an air-liquid interface is associated with a diminished biological effect following particle exposure. This decreased response was not related to differentiation but corresponded to changes in iron homeostasis. This abstract ofa proposed presentation does not reflect EPA policy.