Proteome changes in human bronchoalveolar cells following styrene exposure indicate involvement of oxidative stress in the molecular‐response mechanism

Abstract

Styrene is a volatile organic compound (VOC) that is widely used as an intermediate in many industrial settings. There are known adverse health effects at environmentally significant concentrations, but little is known about the molecular effect of exposure to styrene at subacute toxic concentrations. We exposed human lung epithelial cells, at a wide range of concentrations (1 mg/m3-10 g/m3), to styrene and analyzed the effects on the proteome level by 2-DE, where 1,380 proteins spots were detected and 266 were identified unambiguously by mass spectrometry. A set of 16 protein spots was found to be significantly altered due to exposure to styrene at environmentally significant concentrations of 1-10 mg/m3 (0.2 – 2.3 ppm). Among these, superoxide dismutase [Cu-Zn] as well as biliverdin reductase A could be correlated with the molecular pathway of oxidative stress, while eukaryotic translation initiation factor 5A-1, ezrin, lamin B2 and voltage dependent anion channel 2 have been reported to be involved in apoptosis. Treatment with styrene also caused formation of styrene oxide-protein adducts, specifically for thioredoxin reductase 1. These results underline the relevance of oxidative stress as a primary molecular response mechanism of lung epithelial cells to styrene exposure at indoor-relevant concentrations.

Subtoxic and toxic concentrations of benzene and toluene induce Nrf2-mediated antioxidative stress response and affect the central carbon metabolism in lung epithelial cells A549

“…Human alveolar lung epithelial cells (A549, ATCC No. CCL‐185; LGC Promochem, Wesel, Germany) were cultured in RPMI 1640 medium supplemented with 5% FCS, 1% l ‐glutamine, and 1% Penicillin‐streptomycin as described earlier . Benzene and toluene (purity > 99% GC, Merck, Darmstadt, Germany) were suspended in methanol.…”

“…All the experiments were performed in triplicate. Cells were harvested as described elsewhere . The LDH assay was performed according to the manufacturer's instruction using the cytotoxicity detection kit (Roche Applied Science, Manheim, Germany).…”

“…In order to make sure that we can exclude direct toxicity, we tested beforehand, which concentration of benzene and toluene causes direct toxic effects and excluded them. In addition, other aromatic volatile organic substances such as styrene and chlorobenzene have been tested for their effects on this cell type, before .…”

Quantitative proteomics reveals altered expression of extracellular matrix related proteins of human primary dermal fibroblasts in response to sulfated hyaluronan and collagen applied as artificial extracellular matrix

“…In-gel digestion of protein was performed similar to Mörbt et al [28] with 100 ng trypsin per slice (trypsin sequencing grade from bovine pancreas, Roche, Mannheim, Germany). Samples were concentrated by vacuum centrifugation and reconstituted with 0.1 % (v/v) formic acid after tryptic digestion.…”

Structure-toxicity relationship study of para-halogenated styrene analogues in CYP2E1 transgenic cells

“…Recently, our group reported cellular protein modification by styrene oxide in cultured micro-dissected mouse airways and cells after exposure to styrene (Yuan et al ., 2010). Mörbt et al also identified modified thioredoxin reductase by styrene oxide in cultured A297 cells incubated with styrene (Mörbt et al ., 2009). …”