Online monitoring of volatile organic compounds emitted from human bronchial epithelial cells as markers for oxidative stress.

Particulate air pollution is associated with adverse respiratory effects and is a major factor for premature deaths.In-vitroassays are commonly used for investigating the direct cytotoxicity and inflammatory impacts due to particulate matter (PM) exposure. However, biological tests are often labor-intensive, destructive and limited to endpoints measured offline at single time points, making it impossible to observe the progression of cell response upon exposure. Here we explored the potential of a high-resolution proton transfer reaction mass spectrometer (PTR-MS) to detect the volatile organic compounds (VOCs) emitted by human bronchial epithelial cells (BEAS-2B) upon exposure to PM. Cells were exposed to single components (1,4-naphthoquinone and Cu(II)) known to induce oxidative stress. We also tested filter extracts of aerosols generated in a smog chamber, including fresh and aged wood burning emissions, as well asα-pinene secondary organic aerosol (SOA). We found that 1,4-naphthoquinone was rapidly internalized by the cells. Exposing cells to each of these samples induced the emission of VOCs, which we tentatively assigned to acetonitrile, benzaldehyde and dimethylbenzaldehyde, respectively. Emission rates upon exposure to fresh and aged OA fromα-pinene oxidation and from biomass burning significantly exceeded those observed after exposure to similar doses of Cu(II), a proxy for transition metals with high oxidative potential. Emission rates of biomarkers from cell exposure toα-pinene SOA exhibited a statistically significant, but weak dose dependence. The emission rates of benzaldehyde scaled with cell death, estimated by measuring the apical release of cytosolic lactate dehydrogenase. Particle mass doses delivered to the BEAS-2B cells match those deposited in the human tracheobronchial tract after several hours of inhalation at elevated ambient air pollution. The results presented here show that our method has the potential to determine biomarkers of PM induced pulmonary damage in toxicological and epidemiological research on air pollution.

Expression and secretion of Bluetongue virus serotype 8 (BTV-8)VP2 outer capsid protein by mammalian cells.

VP2 is the outermost Bluetongue virus (BTV) antigenic protein, forming triskelion motifs on the virion surface. Although VP2 has been expressed successfully through many systems, its paracrine expression as a soluble form by mammalian cells represents a difficult task. In the present paper two fragments of VP2 have been expressed successfully into the medium of transiently transfected mammalian cells through a fusion peptides strategy. The crude conditioned medium containing the secreted peptide could be employed for immunodiagnostic assay development or vaccine purposes.