Regulatory Interactions between Androgens, Hoxb5, and TGFβ Signaling in Murine Lung Development
Figure 1
Effect of DHT without and with Hoxb5 knockdown on airway branch development of cultured E11 whole fetal lungs. Images are high-power views (10x Mag) of the left lung of representative ex vivo whole lungs in culture photographed at 24 hour intervals. The dashed lines outline airway branches. Whole lung images are shown in Supplementary Figure 1 (Supplementary Matrial available online at http://dx.doi.org/10.1155/2013/320249). (a) Over the 72 hours of culture all lungs continued to branch, but DHT treatment (DHT and scram/DHT) increased airway arborization compared to control lungs. Hoxb5 siRNA transfection resulted in a disorganized and reduced branching pattern compared to control and DHT-treated lungs. This effect of Hoxb5 siRNA remained even in presence of DHT. (b) Terminal bud counts confirmed that all lungs continued to branch over time in culture. Terminal bud counts at 24 hours of culture were similar in all experimental conditions. At 48 and 72 hours, terminal bud counts were significantly greater in DHT and scramble + DHT treated lungs compared to control and scramble treated lungs (*, , mean ± SEM, control versus DHT and scram versus scram/DHT). Hoxb5 knockdown reduced airway branching at 48 hr compared to scramble control. This difference became significant at 72 hr (#, , mean ± SEM, scram versus Hoxb5 siRNA at 72 hr). Hoxb5 knockdown prevented airway branching induced by DHT treatment at 48 and 72 hours culture (scram/DHT versus Hoxb5 siRNA/DHT, & at 48 hr; # at 72 hr, mean ± SEM, lungs). (c) The velocity of branching (bud velocity) from 24–48 hours was significantly increased with DHT treatment (mean ± SEM; #, control versus DHT; *, scram/DHT versus Hoxb5 siRNA/DHT). (d) The velocity of branching from 48 to 72 hours was significantly inhibited by Hoxb5 knockdown (mean ± SEM; *, Hoxb5 siRNA versus scram).
