Fig. 2. Wnt5a mis/overexpressed lungs show pulmonary hypoplasia with abnormal air and vascular tubulogenesis. (A-C) Whole lungs dissected from wild-type (WT, A), RCAS-Wnt5a-infected (B), and RCAS-Wnt3a-infected (C) embryos at E14, showing pulmonary hypoplasia of the infected lungs. (D-I) H&E-stained lungs showing dramatic thinning of the airway epithelium by mis/overexpression of Wnt5a (compare brackets in E with D) but not following RCAS-Wnt3a infection (compare brackets in G with F). RCAS-Wnt3a mis/overexpressed lungs at E15 have more normal appearing airways and airway epithelial thickness (compare G with F) but develop with abnormal interstitial muscularized vessels, often with extravasated red blood cells (arrows and insert, G). At E20, Wnt5a mis/overexpressing lungs often show pulmonary lymphangiectasia (arrows in I) and disordered larger interstitial vessels (arrowheads, I; compare with wild-type lungs, H). (J-L) At E14, normal developing pulmonary endothelium is localized between airways or parabronchi, as Elderberry bark lectin shows (red arrow, J). With RCAS-Wnt5a infection, the developing vasculature clusters subepithelial to the parabronchi (red arrow, K). The number of elderberry bark lectin-stained interstitial vessels are increased by Wnt3a mis/overexpression but these vessels are localized normally in the interstitium (L), not clustered subepithelially as seen with Wnt5a mis/overexpression (K). Nuclei were counterstained with DAPI (blue). (M,N,O) Cartoon tracings of J,K,L make pattern changes of vasculature clearer. Epithelial cells are orange; endothelial cells, green.