Figure 9

P38 MAPK activation in senescent Clara cells in the airways of COPD patients. (A) Representative photomicrographs of triple immunofluorescence staining of lung tissue sections obtained from COPD patients. Arrows indicate CC10-positive Clara cells that express both p16 and phospho-p38 MAPK. The arrowhead indicates a CC10-positive cell that expresses p16 but not phospho-p38 MAPK (B) Percentages of CC10-positive Clara cells that express p16, CC10-positive Clara cells that express phospho-p38 MAPK, and CC10-positive Clara cells that express both p16 and phospho-p38 MAPK in the lungs of COPD patients (C: n = 14), asymptomatic smokers (S: n = 7), and asymptomatic nonsmokers (NS: n = 8). (C) Correlation between the percentage of CC10-positive Clara cells that express p16 and the percentage of CC10-positive Clara cells that express phospho-p38 MAPK. Open circles = asymptomatic nonsmokers; open triangles = asymptomatic smokers; closed circles = COPD patients. (D) Rates of immunopositivity for phospho-p38 MAPK in CC10-positive Clara cells that express p16 (senescent Clara cells) and in CC10-positive Clara cells that do not express p16 (presenescent Clara cells) in the subjects as a whole, asymptomatic nonsmokers, asymptomatic smokers, and COPD patients.