Proteomic profiling differences in serum from silicosis and chronic bronchitis patients: a comparative analysis.

Background: Silicosis is a severe occupational disease characterized by pulmonary fibrosis, whereas chronic bronchitis (CB) is an acute inflammation of the airways. Differences in the mechanisms of pathogenesis of these diseases are not well understood, therefore we performed proteomic profiling of silicosis and CB patients and, compared the results.

Methods: Two-dimensional gel electrophoresis and MALDI-TOF-MS (matrix assisted laser desorption ionization time of flight mass spectrometry) were used to identify differentially accumulated proteins in stage I of silicosis (SI), stage II of silicosis (SII) and CB. Enzyme linked immunosorbent assay (ELISA) was employed to validate protein expression data.

Results: A total of 28 and 10 proteins were up- and down-regulated in SI, and 21 and 9 proteins were up- and down-regulated SII, compared with CB. Transforming growth factor beta-1 precursor and interferon beta precursor were up-regulated in CB, while interleukin 6, tumor necrosis factor (TNF) and a variant TNF receptor 13B were down-regulated in CB. Additionally, glycoprotein- and apolipoprotein-associated proteins including apolipoprotein A-IV and α-1-B-glycoprotein were up-regulated in CB, indicating an involvement in the pathogenesis of CB but not silicosis. By contrast, HLA-DRB1, medullasin and the proto-oncogene c-Fos were up-regulated in CB.

Conclusions: The immune, metabolism and apolipoprotein-related proteins were identified as playing specific and different roles in silicosis and CB. These proteomic profiling differences would facilitate further studies on the mechanisms underlying silicosis and CB, and may also prove useful to disease diagnosis and treatments.