FGF signalling orchestrates cell-cell junctions and cell fate decisions in salivary gland branching morphogenesis

Many epithelial organs such as lung, kidney, pancreas or salivary glands branch out during morphogenesis to optimise the available surface of the epithelium. In the embryo, Fibroblast Growth Factor (FGF) ligands secreted by the surrounding mesenchyme control both elongation and branching of the epithelium.

However, the intracellular pathways activated downstream the receptor and the specific transcriptional changes that occur in the epithelial cells upon signalling are not completely understood. Using the murine Salivary Gland (SG) as a model for branching morphogenesis, we have taken advantage of its ease of ex vivo culture to identify the molecular players downstream of FGF during branching. We compared the morphological and transcriptional changes that occur by pharmaceutical inhibition vs genetic deletion of FGF receptors and found a dependence of FGF for the correct coordination of nerves and blood vessels growth with gland epithelium.