Patched1 patterns Fibroblast growth factor 10 and Forkhead box F1 expression during pulmonary branch formation

Publication date: Available online 20 September 2017 Source:Mechanisms of Development Author(s): Uda Y. Ho, Brandon J. Wainwright Hedgehog (Hh) signalling, Fibroblast growth factor 10 (Fgf10) and Forkhead box F1 (Foxf1) are each individually important for directing pulmonary branch formation but their interactions are not well understood. Here we demonstrate that Hh signalling is vital in regulating Foxf1 and Fgf10 expression during branching. The Hedgehog receptor Patched1 (Ptch1) was conditionally inactivated in the lung mesenchyme by Dermo1-Cre in vivo or using a recombinant Cre recombinase protein (HNCre) in lung cultures resulting in cell autonomous activation of Hh signalling. Homozygous mesenchymal Ptch1 deleted embryos (Dermo1Cre +/−;Ptch1 lox/lox ) showed secondary branching and lobe formation defects. Fgf10 expression is spatially reduced in the distal tip of Dermo1Cre +/−;Ptch1 lox/lox lungs and addition of Fgf10 recombinant protein to these lungs in culture has shown partial restoration of branching, indicating Ptch1 function patterns Fgf10 to direct lung branching. Foxf1 expression is upregulated in Dermo1Cre +/−;Ptch1 lox/lox lungs, suggesting Foxf1 may mediate Hh signalling effects in the lung mesenchyme. In vitro HNCre-mediated Ptch1 deleted lung explants support the in vivo observations, with evidence of mesenchyme hyperproliferation and this is consistent with the previously reported role of Hh signalling in maintaining mesenchymal cell survival. C...

Source: Mechanisms of Development - September 21, 2017 Category: Biology Source Type: research