Expression of Tcf/Lef and sFrp and localization of β-catenin in the developing mouse lung

Abstract

Recent evidence that Wnts and other genes in the Wnt signaling pathway are expressed in embryonic and adult mouse lung suggests that this pathway is important for cell fate decisions and differentiation of lung cell types. We therefore examined the expression and protein distribution of several Wnt pathway components during prenatal mouse lung development using whole-mount in situ hybridization and immunohistochemistry. Between embryonic days 10.5 and 17.5 (E10.5-E17.5), beta-catenin was localized in the cytoplasm, and often also the nucleus, of the undifferentiated primordial epithelium (PE), differentiating alveolar epithelium (AE; present from E14.5 onward), and adjacent mesenchyme. Tcf1, Lef1, Tcf3, Tcf4, sFrp1, sFrp2 and sFrp4 were also expressed in the PE, AE, and adjacent mesenchyme in specific spatio-temporal patterns.

Wnt Signaling and Pulmonary Fibrosis

“…Other reports support these observations during mouse lung development. 42 Type 2 pneumocytes appear to express high levels of ␤-catenin both in the embryo and in the adult (current study). 42 Type 2 cells are precursors of type 1 cells, which form the thin diffusible stratum important for gas exchange in the lung.…”

“…42 Type 2 pneumocytes appear to express high levels of ␤-catenin both in the embryo and in the adult (current study). 42 Type 2 cells are precursors of type 1 cells, which form the thin diffusible stratum important for gas exchange in the lung. Type 2 cells have been shown to re-enter the cell cycle, grow, and differentiate into type 1 cells in some models of lung re-epithelialization.…”

Wnt7b stimulates embryonic lung growth by coordinately increasing the replication of epithelium and mesenchyme

“…5A) (De Langhe et al, 2005;Dean et al, 2005;Okubo and Hogan, 2004;Shu et al, 2005). As previously described, Axin2 and Lef1 were also expressed in the mesenchyme immediately surrounding the distal endoderm (De Langhe et al, 2005;Jho et al, 2002;Tebar et al, 2001). Wnt7b-null lungs did not express either of these genes in mesenchyme or endoderm.…”

R-spondin 2 is required for normal laryngeal-tracheal, lung and limb morphogenesis

“…The early epithelium expresses Wnt7b and Lrp6, whereas the mesenchyme expresses Wnt2a (De Langhe et al, 2005;Wang et al, 2005). Both tissues express Wnt11, Wnt5a and ␤-catenin (Li et al, 2002;Tebar et al, 2001;Weidenfeld et al, 2002). Wnt5a -/-fetuses exhibit truncation of the trachea, overexpansion of distal airways and disrupted lung maturation (Li et al, 2002).…”