Conclusions
MMP-13 and thioredoxin-like 2 in lungs increased in patients with COPD. MMP-13 was mainly expressed in the alveolar macrophages and type II pneumocytes. In contrast, thioredoxin-like 2 was primarily seen in the bronchial epithelium.
Methods
Nontumorous lung tissue specimens were obtained from patients who underwent surgery for lung cancer. We included 22 subjects: nonsmokers (n = 8), smokers without COPD (healthy smokers, n = 7), and smokers with COPD (n = 7). Proteins were separated from their spots with two-dimensional polyacrylamide gel electrophoresis and examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). To validate the proteins from the above procedures, Western blotting and immunohistochemistry were conducted.
Results
Twelve protein spots from COPD group significantly increased or decreased compared with the other two groups were chosen for MALDI-TOF-MS analysis. Eight proteins were up-regulated in the COPD group as compared with the nonsmokers. Meanwhile, five proteins from the COPD group were up-regulated and five were down-regulated when compared with healthy smokers. Of these, matrix metalloproteinase (MMP)-13 and thioredoxin-like 2 were significantly increased in the COPD patients by Western blot and immunohistochemistry. MMP-13 was mainly expressed in the alveolar macrophages and type II pneumocytes; however, thioredoxin-like 2 was primarily seen in the bronchial epithelium. Conclusions: MMP-13 and thioredoxin-like 2 in lungs increased in patients with COPD. MMP-13 was mainly expressed in the alveolar macrophages and type II pneumocytes. In contrast, thioredoxin-like 2 was primarily seen in the bronchial epithelium.