Proteomic identification of the differentially expressed proteins in human lung epithelial cells by airborne particulate matter

Exposure to airborne PM₁₀, particulate matter with a median aerodynamic diameter of less than 10 µm, is known to be associated with a number of adverse health effects. To gain a better understanding of the cytotoxic mechanism and to develop protein biomarker candidates for PM₁₀‐induced toxicity, proteomic analyses were performed in human lung epithelial cells. Two‐dimensional gel electrophoresis (2‐DE) was followed by matrix‐assisted laser desorption/ionization–time of flight mass spectrometry (MALDI‐TOF MS) to analyze the proteins differentially expressed by exposure to PM₁₀. Analysis of 2‐DE gels revealed more than 1270 protein spots in the cells, of which 36 showed changes of more than 2‐fold on exposure to PM₁₀ (up‐regulation, n = 6; down‐regulation, n = 30). The glycolytic enzyme pyruvate kinase, which also plays a role in tumor metabolism, showed a marked increase in expression, whereas the cytoskeleton‐related vinculin and anti‐inflammatory annexin 1 showed marked decreases in expression.