Enhanced p-Smad2 signaling in the alveolar epithelial cells (AECs) of
CD151 knockout (KO) mice. (A) Western blot analysis and
densitometric quantification of p-Smad2 in total protein homogenates
from wild-type (WT) and CD151 KO lungs. Values of p-Smad2 were
normalized against total Smad2. *P < 0.001.
(B) Western blot analysis and densitometric
quantification of Smad7 and p-Akt in total protein homogenates from WT
and CD151 KO lungs. Values of Smad7, p-Akt, and p-Erk1/2 were normalized
against GAPDH, Akt, and Erk, respectively. (C,
D) Immunofluorescence of mouse lungs stained for
p-Smad2 and TTF-1 or CD11b. The numbers of p-Smad2 and TTF-1
double-positive AECs (arrows) were significantly larger
in CD151 KO lungs (C, n = 4 per group,
†P < 0.05). p-Smad2−positive signals
were scarcely seen in CD11b-positive alveolar macrophages
(D, arrowheads). Bar = 100 μm.
(E) Activated TGF-β1 in whole lung was
measured by ELISA and normalized against total protein. Levels of
activated TGF-β1 were comparable between WT and CD151 KO
lungs (n = 3 per group).