Akt activation in lung epithelium results in defective maturation of lung epithelial cells and expansion of CC10/SP-C double-positive cells. (A) Western blot analysis of surfactant proteins (SP-A, SP-B, pro-SP-C, and SP-D), CC10 (a marker of Clara cells), and AQP5 (a marker of type I alveolar cells). Lower panels show densitometric analysis. *, P < 0.05 versus control (n = 4 mice from 2 dams for both controls and DTG). (B) Immunohistochemical analysis of HA tag (Akt1 transgene), SP-C, CC10, and AQP5. SP-C, CC10, and AQP5 were detected in cuboidal type II alveolar cells, Clara cells, and flat type I alveolar cells, respectively. Scale bar, 50 μm. (C and D). Double immunostaining of CC10 and SP-C. CC10/SP-C double-positive cells are indicated by arrows. Scale bar, 100 μm. *, P < 0.05 versus control (n = 5 control and n = 3 DTG mice from 3 dams).