Fgf-10 induces SPC and bmp4 and regulates proximal-distal patterning in embryonic tracheal epithelium

Physiol 287: L1116–L1126, 2004; doi:10.1152/ajplung.00033.2004.— The induction, growth, and differentiation of epithelial lung buds are regulated by the interaction of signals between the lung epithelium and its surrounding mesenchyme. Fibroblast growth factor-10 (FGF-10), which is expressed in the mesenchyme near the distal tips, and bone morphogenetic protein 4 (BMP4), which is expressed in the most distal regions of the epithelium, are important molecules in lung morphogenesis. In the present study, we used two in vitro systems to examine the induction, growth, and differentiation of lung epithelium. Transfilter cultures were used to determine the effect of diffusible factors from the distal lung mesenchyme (LgM) on epithelial branch-ing, and FGF-10 bead cultures were used to ascertain the effect of a high local concentration of a single diffusible molecule on the epi-thelium. Embryonic tracheal epithelium (TrE) was induced to grow in both culture systems and to express the distal epithelial marke